Bellini, Catherine - Control of Adventitious Root Initiation and Phloem Function

@article{bellini_synthetic_2024,
	title = {A synthetic auxin for cloning mature trees},
	copyright = {2024 Springer Nature America, Inc.},
	issn = {1546-1696},
	url = {https://www.nature.com/articles/s41587-024-02132-3},
	doi = {10.1038/s41587-024-02132-3},
	abstract = {A synthetic auxin improves the growth of adventitious roots in various plant species.},
	language = {en},
	urldate = {2024-10-07},
	journal = {Nature Biotechnology},
	author = {Bellini, Catherine},
	month = jan,
	year = {2024},
	note = {Publisher: Nature Publishing Group},
	keywords = {Auxin, Plant regeneration},
	pages = {1--2},
}

A synthetic auxin improves the growth of adventitious roots in various plant species.

@incollection{mishra_adventitious_2024,
	edition = {5},
	title = {Adventitious {Root} {Development} in {Dicotyledons}},
	isbn = {978-1-00-332494-2},
	abstract = {The plant's root system is comprised of primary, lateral, and adventitious roots (ARs). Lateral roots emerge exclusively from existing roots, whereas ARs originate from stem- or leaf-derived cells. The progression of adventitious root development is a natural part of a plant's growth, commonly observed in most monocotyledonous species where they establish the primary root system or in various dicotyledonous plants that reproduce vegetatively. Adventitious rooting holds particular significance in the propagation of economically valuable horticultural and woody species, enabling the cloning of plants and swift establishment of superior genotypes before integrating them into production or breeding schemes. The process of AR development is intricate and influenced by numerous intrinsic and environmental factors, encompassing phytohormones, light exposure, nutritional state, stress responses like injury, and genetic traits. This chapter provides an overview of the latest advancements in research concerning adventitious root formation, with a specific focus on the interplay of key hormones and their interactions, as well as the influence of light, a significant environmental factor.},
	booktitle = {Plant {Roots}},
	publisher = {CRC Press},
	author = {Mishra, Priyanka and Kidwai, Maria and Lakehal, Abdellah and Bellini, Catherine},
	year = {2024},
	note = {Num Pages: 13},
}

The plant's root system is comprised of primary, lateral, and adventitious roots (ARs). Lateral roots emerge exclusively from existing roots, whereas ARs originate from stem- or leaf-derived cells. The progression of adventitious root development is a natural part of a plant's growth, commonly observed in most monocotyledonous species where they establish the primary root system or in various dicotyledonous plants that reproduce vegetatively. Adventitious rooting holds particular significance in the propagation of economically valuable horticultural and woody species, enabling the cloning of plants and swift establishment of superior genotypes before integrating them into production or breeding schemes. The process of AR development is intricate and influenced by numerous intrinsic and environmental factors, encompassing phytohormones, light exposure, nutritional state, stress responses like injury, and genetic traits. This chapter provides an overview of the latest advancements in research concerning adventitious root formation, with a specific focus on the interplay of key hormones and their interactions, as well as the influence of light, a significant environmental factor.

@article{zeng_chemical_2023,
	title = {Chemical induction of hypocotyl rooting reveals extensive conservation of auxin signalling controlling lateral and adventitious root formation},
	volume = {240},
	copyright = {© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation},
	issn = {1469-8137},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/nph.19292},
	doi = {10.1111/nph.19292},
	abstract = {Upon exposure to light, etiolated Arabidopsis seedlings form adventitious roots (AR) along the hypocotyl. While processes underlying lateral root formation are studied intensively, comparatively little is known about the molecular processes involved in the initiation of hypocotyl AR. AR and LR formation were studied using a small molecule named Hypocotyl Specific Adventitious Root INducer (HYSPARIN) that strongly induces AR but not LR formation. HYSPARIN does not trigger rapid DR5-reporter activation, DII-Venus degradation or Ca2+ signalling. Transcriptome analysis, auxin signalling reporter lines and mutants show that HYSPARIN AR induction involves nuclear TIR1/AFB and plasma membrane TMK auxin signalling, as well as multiple downstream LR development genes (SHY2/IAA3, PUCHI, MAKR4 and GATA23). Comparison of the AR and LR induction transcriptome identified SAURs, AGC kinases and OFP transcription factors as specifically upregulated by HYSPARIN. Members of the SAUR19 subfamily, OFP4 and AGC2 suppress HYS-induced AR formation. While SAUR19 and OFP subfamily members also mildly modulate LR formation, AGC2 regulates only AR induction. Analysis of HYSPARIN-induced AR formation uncovers an evolutionary conservation of auxin signalling controlling LR and AR induction in Arabidopsis seedlings and identifies SAUR19, OFP4 and AGC2 kinase as novel regulators of AR formation.},
	language = {en},
	number = {5},
	urldate = {2023-11-10},
	journal = {New Phytologist},
	author = {Zeng, Yinwei and Verstraeten, Inge and Trinh, Hoang Khai and Lardon, Robin and Schotte, Sebastien and Olatunji, Damilola and Heugebaert, Thomas and Stevens, Christian and Quareshy, Mussa and Napier, Richard and Nastasi, Sara Paola and Costa, Alex and De Rybel, Bert and Bellini, Catherine and Beeckman, Tom and Vanneste, Steffen and Geelen, Danny},
	month = oct,
	year = {2023},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/nph.19292},
	keywords = {adventitious root, auxin signalling, root branching, root development, synthetic auxin},
	pages = {1883--1899},
}

Upon exposure to light, etiolated Arabidopsis seedlings form adventitious roots (AR) along the hypocotyl. While processes underlying lateral root formation are studied intensively, comparatively little is known about the molecular processes involved in the initiation of hypocotyl AR. AR and LR formation were studied using a small molecule named Hypocotyl Specific Adventitious Root INducer (HYSPARIN) that strongly induces AR but not LR formation. HYSPARIN does not trigger rapid DR5-reporter activation, DII-Venus degradation or Ca2+ signalling. Transcriptome analysis, auxin signalling reporter lines and mutants show that HYSPARIN AR induction involves nuclear TIR1/AFB and plasma membrane TMK auxin signalling, as well as multiple downstream LR development genes (SHY2/IAA3, PUCHI, MAKR4 and GATA23). Comparison of the AR and LR induction transcriptome identified SAURs, AGC kinases and OFP transcription factors as specifically upregulated by HYSPARIN. Members of the SAUR19 subfamily, OFP4 and AGC2 suppress HYS-induced AR formation. While SAUR19 and OFP subfamily members also mildly modulate LR formation, AGC2 regulates only AR induction. Analysis of HYSPARIN-induced AR formation uncovers an evolutionary conservation of auxin signalling controlling LR and AR induction in Arabidopsis seedlings and identifies SAUR19, OFP4 and AGC2 kinase as novel regulators of AR formation.

@article{kidwai_species-specific_2023,
	title = {Species-specific transcriptional reprogramming during adventitious root initiation},
	volume = {28},
	issn = {1360-1385},
	url = {https://www.sciencedirect.com/science/article/pii/S1360138522003028},
	doi = {10.1016/j.tplants.2022.11.003},
	abstract = {Adventitious roots or shoot-borne roots transdifferentiate from cells close to vascular tissues after cell reprogramming, which is associated with increased transcriptional activity. Recently, Garg et al. provided a genome-wide landscape of transcriptional signatures during the early stages of adventitious root initiation in rice and showed that conserved transcription factors acquire species-specific function.},
	language = {en},
	number = {2},
	urldate = {2023-01-26},
	journal = {Trends in Plant Science},
	author = {Kidwai, Maria and Mishra, Priyanka and Bellini, Catherine},
	month = feb,
	year = {2023},
	keywords = {adventitious root, dicotyledons, epigenetic regulation, monocotyledons, transcription factors},
	pages = {128--130},
}

Adventitious roots or shoot-borne roots transdifferentiate from cells close to vascular tissues after cell reprogramming, which is associated with increased transcriptional activity. Recently, Garg et al. provided a genome-wide landscape of transcriptional signatures during the early stages of adventitious root initiation in rice and showed that conserved transcription factors acquire species-specific function.

@article{aubry_vacuolar_2022,
	title = {A vacuolar hexose transport is required for xylem development in the inflorescence stem},
	volume = {188},
	issn = {0032-0889},
	url = {https://doi.org/10.1093/plphys/kiab551},
	doi = {10.1093/plphys/kiab551},
	abstract = {In Angiosperms, the development of the vascular system is controlled by a complex network of transcription factors. However, how nutrient availability in the vascular cells affects their development remains to be addressed. At the cellular level, cytosolic sugar availability is regulated mainly by sugar exchanges at the tonoplast through active and/or facilitated transport. In Arabidopsis (Arabidopsis thaliana), among the genes encoding tonoplastic transporters, SUGAR WILL EVENTUALLY BE EXPORTED TRANSPORTER 16 (SWEET16) and SWEET17 expression has been previously detected in the vascular system. Here, using a reverse genetics approach, we propose that sugar exchanges at the tonoplast, regulated by SWEET16, are important for xylem cell division as revealed in particular by the decreased number of xylem cells in the swt16 mutant and the accumulation of SWEET16 at the procambium–xylem boundary. In addition, we demonstrate that transport of hexoses mediated by SWEET16 and/or SWEET17 is required to sustain the formation of the xylem secondary cell wall. This result is in line with a defect in the xylem cell wall composition as measured by Fourier-transformed infrared spectroscopy in the swt16swt17 double mutant and by upregulation of several genes involved in secondary cell wall synthesis. Our work therefore supports a model in which xylem development partially depends on the exchange of hexoses at the tonoplast of xylem-forming cells.},
	number = {2},
	urldate = {2022-03-31},
	journal = {Plant Physiology},
	author = {Aubry, Emilie and Hoffmann, Beate and Vilaine, Françoise and Gilard, Françoise and Klemens, Patrick A W and Guérard, Florence and Gakière, Bertrand and Neuhaus, H Ekkehard and Bellini, Catherine and Dinant, Sylvie and Le Hir, Rozenn},
	month = feb,
	year = {2022},
	pages = {1229--1247},
}

In Angiosperms, the development of the vascular system is controlled by a complex network of transcription factors. However, how nutrient availability in the vascular cells affects their development remains to be addressed. At the cellular level, cytosolic sugar availability is regulated mainly by sugar exchanges at the tonoplast through active and/or facilitated transport. In Arabidopsis (Arabidopsis thaliana), among the genes encoding tonoplastic transporters, SUGAR WILL EVENTUALLY BE EXPORTED TRANSPORTER 16 (SWEET16) and SWEET17 expression has been previously detected in the vascular system. Here, using a reverse genetics approach, we propose that sugar exchanges at the tonoplast, regulated by SWEET16, are important for xylem cell division as revealed in particular by the decreased number of xylem cells in the swt16 mutant and the accumulation of SWEET16 at the procambium–xylem boundary. In addition, we demonstrate that transport of hexoses mediated by SWEET16 and/or SWEET17 is required to sustain the formation of the xylem secondary cell wall. This result is in line with a defect in the xylem cell wall composition as measured by Fourier-transformed infrared spectroscopy in the swt16swt17 double mutant and by upregulation of several genes involved in secondary cell wall synthesis. Our work therefore supports a model in which xylem development partially depends on the exchange of hexoses at the tonoplast of xylem-forming cells.

@incollection{bellini_adventitious_2022,
	title = {Adventitious {Roots}},
	copyright = {Copyright © 2022 John Wiley \& Sons, Ltd.},
	isbn = {978-0-470-01590-2},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/9780470015902.a0029521},
	abstract = {The root system of a plant is composed of the primary, lateral and adventitious roots (ARs). Lateral roots always develop from roots, whereas ARs form from stem or leaf-derived cells. AR development (ARD) is part of the normal development of the plant and occurs naturally, like in most monocotyledonous for which they constitute the main root system or in many dicotyledonous species that propagate vegetatively. Adventitious rooting is an essential step for vegetative propagation of economically important horticultural and woody species as it allows clonal propagation and rapid fixation of superior genotypes prior to their introduction into production or breeding programmes. Development of ARs is a complex process that is affected by multiple endogenous and environmental factors, including phytohormones, light, nutritional status, associated stress responses, such as wounding, and genetic characteristics. Key Concepts ARs are a prerequisite for vegetative propagation of plants. ARs arise from any organ of the plant but the root. ARs originate from different cell types depending on the organ or the species. Adventitious rooting is a complex quantitative genetic trait. ARs are the main root system for monocots. ARs can be adaptative response to environmental changes. ARs can be induced by interaction with micro-organisms such as mycorrhizae or bacteria Auxin cross-talks with other hormones to control adventitious rooting.},
	language = {en},
	urldate = {2024-10-07},
	booktitle = {{eLS}},
	publisher = {John Wiley \& Sons, Ltd},
	author = {Bellini, Catherine},
	year = {2022},
	doi = {10.1002/9780470015902.a0029521},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/9780470015902.a0029521},
	keywords = {abiotic stress, adventitious root, biotic stress, in vitro culture, plant hormones, root development, vegetative propagation},
	pages = {1--9},
}

The root system of a plant is composed of the primary, lateral and adventitious roots (ARs). Lateral roots always develop from roots, whereas ARs form from stem or leaf-derived cells. AR development (ARD) is part of the normal development of the plant and occurs naturally, like in most monocotyledonous for which they constitute the main root system or in many dicotyledonous species that propagate vegetatively. Adventitious rooting is an essential step for vegetative propagation of economically important horticultural and woody species as it allows clonal propagation and rapid fixation of superior genotypes prior to their introduction into production or breeding programmes. Development of ARs is a complex process that is affected by multiple endogenous and environmental factors, including phytohormones, light, nutritional status, associated stress responses, such as wounding, and genetic characteristics. Key Concepts ARs are a prerequisite for vegetative propagation of plants. ARs arise from any organ of the plant but the root. ARs originate from different cell types depending on the organ or the species. Adventitious rooting is a complex quantitative genetic trait. ARs are the main root system for monocots. ARs can be adaptative response to environmental changes. ARs can be induced by interaction with micro-organisms such as mycorrhizae or bacteria Auxin cross-talks with other hormones to control adventitious rooting.

@article{cardoso_editorial_2022,
	title = {Editorial: {Advances} on the {Biological} {Mechanisms} {Involved} in {Adventitious} {Root} {Formation}: {From} {Signaling} to {Morphogenesis}},
	volume = {13},
	issn = {1664-462X},
	shorttitle = {Editorial},
	url = {https://www.frontiersin.org/article/10.3389/fpls.2022.867651},
	doi = {10.3389/fpls.2022.867651},
	urldate = {2022-03-25},
	journal = {Frontiers in Plant Science},
	author = {Cardoso, Hélia and Peixe, Augusto and Bellini, Catherine and Porfírio, Sara and Druege, Uwe},
	year = {2022},
}

@article{ranjan_molecular_2022,
	title = {Molecular basis of differential adventitious rooting competence in poplar genotypes},
	volume = {73},
	issn = {0022-0957},
	url = {https://doi.org/10.1093/jxb/erac126},
	doi = {10.1093/jxb/erac126},
	abstract = {Recalcitrant adventitious root (AR) development is a major hurdle in propagating commercially important woody plants. Although significant progress has been made to identify genes involved in subsequent steps of AR development, the molecular basis of differences in apparent recalcitrance to form AR between easy-to-root and difficult-to-root genotypes remains unknown. To address this, we generated cambium tissue-specific transcriptomic data from stem cuttings of hybrid aspen, T89 (difficult-to-root) and hybrid poplar OP42 (easy-to-root), and used transgenic approaches to verify the role of several transcription factors in the control of adventitious rooting. Increased peroxidase activity was positively correlated with better rooting. We found differentially expressed genes encoding reactive oxygen species scavenging proteins to be enriched in OP42 compared with T89. A greater number of differentially expressed transcription factors in cambium cells of OP42 compared with T89 was revealed by a more intense transcriptional reprograming in the former. PtMYC2, a potential negative regulator, was less expressed in OP42 compared with T89. Using transgenic approaches, we demonstrated that PttARF17.1 and PttMYC2.1 negatively regulate adventitious rooting. Our results provide insights into the molecular basis of genotypic differences in AR and implicate differential expression of the master regulator MYC2 as a critical player in this process.},
	number = {12},
	urldate = {2022-06-30},
	journal = {Journal of Experimental Botany},
	author = {Ranjan, Alok and Perrone, Irene and Alallaq, Sanaria and Singh, Rajesh and Rigal, Adeline and Brunoni, Federica and Chitarra, Walter and Guinet, Frederic and Kohler, Annegret and Martin, Francis and Street, Nathaniel R and Bhalerao, Rishikesh and Legué, Valérie and Bellini, Catherine},
	month = jun,
	year = {2022},
	pages = {4046--4064},
}

Recalcitrant adventitious root (AR) development is a major hurdle in propagating commercially important woody plants. Although significant progress has been made to identify genes involved in subsequent steps of AR development, the molecular basis of differences in apparent recalcitrance to form AR between easy-to-root and difficult-to-root genotypes remains unknown. To address this, we generated cambium tissue-specific transcriptomic data from stem cuttings of hybrid aspen, T89 (difficult-to-root) and hybrid poplar OP42 (easy-to-root), and used transgenic approaches to verify the role of several transcription factors in the control of adventitious rooting. Increased peroxidase activity was positively correlated with better rooting. We found differentially expressed genes encoding reactive oxygen species scavenging proteins to be enriched in OP42 compared with T89. A greater number of differentially expressed transcription factors in cambium cells of OP42 compared with T89 was revealed by a more intense transcriptional reprograming in the former. PtMYC2, a potential negative regulator, was less expressed in OP42 compared with T89. Using transgenic approaches, we demonstrated that PttARF17.1 and PttMYC2.1 negatively regulate adventitious rooting. Our results provide insights into the molecular basis of genotypic differences in AR and implicate differential expression of the master regulator MYC2 as a critical player in this process.

@article{chardon_natural_2022,
	title = {Natural variation in the long-distance transport of nutrients and photoassimilates in response to {N} availability},
	volume = {273},
	issn = {0176-1617},
	url = {https://www.sciencedirect.com/science/article/pii/S0176161722000931},
	doi = {10.1016/j.jplph.2022.153707},
	abstract = {Phloem and xylem tissues are necessary for the allocation of nutrients and photoassimilates. However, how the long-distance transport of carbon (C) and nitrogen (N) is coordinated with the central metabolism is largely unknown. To better understand how the genetic and environmental factors influence C and N transport, we analysed the metabolite profiles of phloem exudates and xylem saps of five Arabidopsis thaliana accessions grown in low or non-limiting N supply. We observed that xylem saps were composed of 46 or 56\% carbohydrates, 27 or 45\% amino acids, and 5 or 13\% organic acids in low or non-limiting N supply, respectively. In contrast, phloem exudates were composed of 76 or 86\% carbohydrates, 7 or 18\% amino acids, and 5 or 6\% organic acids. Variation in N supply impacted amino acid, organic acid and sugar contents. When comparing low N and non-limiting N, the most striking differences were variations of glutamine, aspartate, and succinate abundance in the xylem saps and citrate and fumarate abundance in phloem exudates. In addition, we observed a substantial variation of metabolite content between genotypes, particularly under high N. The content of several organic acids, such as malate, citrate, fumarate, and succinate was affected by the genotype alone or by the interaction between genotype and N supply. This study confirmed that the response of the transport of nutrients in the phloem and the xylem to N availability is associated with the regulation of the central metabolism and could be an adaptive trait.},
	language = {en},
	urldate = {2022-05-30},
	journal = {Journal of Plant Physiology},
	author = {Chardon, Fabien and De Marco, Federica and Marmagne, Anne and Le Hir, Rozenn and Vilaine, Françoise and Bellini, Catherine and Dinant, Sylvie},
	month = jun,
	year = {2022},
	keywords = {Allocation, Pipecolate, Raffinose, Succinate, Sucrose, Transport},
	pages = {153707},
}

Phloem and xylem tissues are necessary for the allocation of nutrients and photoassimilates. However, how the long-distance transport of carbon (C) and nitrogen (N) is coordinated with the central metabolism is largely unknown. To better understand how the genetic and environmental factors influence C and N transport, we analysed the metabolite profiles of phloem exudates and xylem saps of five Arabidopsis thaliana accessions grown in low or non-limiting N supply. We observed that xylem saps were composed of 46 or 56% carbohydrates, 27 or 45% amino acids, and 5 or 13% organic acids in low or non-limiting N supply, respectively. In contrast, phloem exudates were composed of 76 or 86% carbohydrates, 7 or 18% amino acids, and 5 or 6% organic acids. Variation in N supply impacted amino acid, organic acid and sugar contents. When comparing low N and non-limiting N, the most striking differences were variations of glutamine, aspartate, and succinate abundance in the xylem saps and citrate and fumarate abundance in phloem exudates. In addition, we observed a substantial variation of metabolite content between genotypes, particularly under high N. The content of several organic acids, such as malate, citrate, fumarate, and succinate was affected by the genotype alone or by the interaction between genotype and N supply. This study confirmed that the response of the transport of nutrients in the phloem and the xylem to N availability is associated with the regulation of the central metabolism and could be an adaptive trait.

@article{bannoud_adventitious_2021,
	title = {Adventitious {Rooting} in {Populus} {Species}: {Update} and {Perspectives}},
	volume = {12},
	issn = {1664-462X},
	shorttitle = {Adventitious {Rooting} in {Populus} {Species}},
	url = {https://www.frontiersin.org/articles/10.3389/fpls.2021.668837/full},
	doi = {10/gkhp7k},
	abstract = {Populus spp. are among the most economically important species worldwide. These trees are used not only for wood and fiber production, but also in the rehabilitation of degraded lands. Since they are clonally propagated, the ability of stem cuttings to form adventitious roots is a critical point for plant establishment and survival in the field, and consequently for the forest industry. Adventitious rooting in different Populus clones has been an agronomic trait targeted in breeding programs for many years, and many factors have been identified that affect this quantitative trait. A huge variation in the rooting capacity has been observed among the species in the Populus genus, and the responses to some of the factors affecting this trait have been shown to be genotype-dependent. This review analyses similarities and differences between results obtained from studies examining the role of internal and external factors affecting rooting of Populus species cuttings. Since rooting is the most important requirement for stand establishment in clonally propagated species, understanding the physiological and genetic mechanisms that promote this trait is essential for successful commercial deployment.},
	language = {English},
	urldate = {2021-06-17},
	journal = {Frontiers in Plant Science},
	author = {Bannoud, Florencia and Bellini, Catherine},
	year = {2021},
	keywords = {Adventitious rooting, Populus, Vegetative propagation, adventitious rooting, endogenous factors, environmental factors, vegetative propagation},
}

Populus spp. are among the most economically important species worldwide. These trees are used not only for wood and fiber production, but also in the rehabilitation of degraded lands. Since they are clonally propagated, the ability of stem cuttings to form adventitious roots is a critical point for plant establishment and survival in the field, and consequently for the forest industry. Adventitious rooting in different Populus clones has been an agronomic trait targeted in breeding programs for many years, and many factors have been identified that affect this quantitative trait. A huge variation in the rooting capacity has been observed among the species in the Populus genus, and the responses to some of the factors affecting this trait have been shown to be genotype-dependent. This review analyses similarities and differences between results obtained from studies examining the role of internal and external factors affecting rooting of Populus species cuttings. Since rooting is the most important requirement for stand establishment in clonally propagated species, understanding the physiological and genetic mechanisms that promote this trait is essential for successful commercial deployment.

@article{dob_jasmonate_2021,
	title = {Jasmonate inhibits adventitious root initiation through repression of {CKX1} and activation of {RAP2}.{6L} transcription factor in {Arabidopsis}},
	volume = {72},
	issn = {0022-0957},
	url = {https://doi.org/10.1093/jxb/erab358},
	doi = {10.1093/jxb/erab358},
	abstract = {Adventitious rooting is a de novo organogenesis process that enables plants to propagate clonally and cope with environmental stresses. Adventitious root initiation (ARI) is controlled by interconnected transcriptional and hormonal networks, but there is little knowledge of the genetic and molecular programs orchestrating these networks. Thus, we have applied genome-wide transcriptome profiling to elucidate the profound transcriptional reprogramming events preceding ARI. These reprogramming events are associated with the downregulation of cytokinin (CK) signaling and response genes, which could be triggers for ARI. Interestingly, we found that CK free-base (iP, tZ, cZ and DHZ) content declined during ARI, due to downregulation of de novo CK biosynthesis and upregulation of CK inactivation pathways. We also found that MYC2-dependent jasmonate (JA) signaling inhibits ARI by downregulating the expression of the CYTOKININ OXIDASE/DEHYDROGENASE1 (CKX1) gene. We also demonstrated that JA and CK synergistically activate expression of RELATED to APETALA2.6 LIKE (RAP2.6L) transcription factor, and constitutive expression of this transcription factor strongly inhibits ARI. Collectively, our findings reveal that previously unknown genetic interactions between JA and CK play key roles in ARI},
	number = {20},
	urldate = {2021-08-18},
	journal = {Journal of Experimental Botany},
	author = {Dob, Asma and Lakehal, Abdellah and Novak, Ondrej and Bellini, Catherine},
	month = jul,
	year = {2021},
	keywords = {Adventitious roots, Arabidopsis, Arabidopsis Proteins, CKX1, Cyclopentanes, Gene Expression Regulation, Plant, MYC2, Oxylipins, Plant Roots, RAP2.6L, Transcription Factors, cytokinins, jasmonate, light, vegetative propagation},
	pages = {7107--7118},
}

Adventitious rooting is a de novo organogenesis process that enables plants to propagate clonally and cope with environmental stresses. Adventitious root initiation (ARI) is controlled by interconnected transcriptional and hormonal networks, but there is little knowledge of the genetic and molecular programs orchestrating these networks. Thus, we have applied genome-wide transcriptome profiling to elucidate the profound transcriptional reprogramming events preceding ARI. These reprogramming events are associated with the downregulation of cytokinin (CK) signaling and response genes, which could be triggers for ARI. Interestingly, we found that CK free-base (iP, tZ, cZ and DHZ) content declined during ARI, due to downregulation of de novo CK biosynthesis and upregulation of CK inactivation pathways. We also found that MYC2-dependent jasmonate (JA) signaling inhibits ARI by downregulating the expression of the CYTOKININ OXIDASE/DEHYDROGENASE1 (CKX1) gene. We also demonstrated that JA and CK synergistically activate expression of RELATED to APETALA2.6 LIKE (RAP2.6L) transcription factor, and constitutive expression of this transcription factor strongly inhibits ARI. Collectively, our findings reveal that previously unknown genetic interactions between JA and CK play key roles in ARI

@article{brunoni_conifers_2020,
	title = {Conifers exhibit a characteristic inactivation of auxin to maintain tissue homeostasis},
	volume = {226},
	issn = {0028-646X, 1469-8137},
	url = {https://onlinelibrary.wiley.com/doi/10.1111/nph.16463},
	doi = {10.1111/nph.16463},
	language = {en},
	number = {6},
	urldate = {2021-06-07},
	journal = {New Phytologist},
	author = {Brunoni, Federica and Collani, Silvio and Casanova‐Sáez, Rubén and Šimura, Jan and Karady, Michal and Schmid, Markus and Ljung, Karin and Bellini, Catherine},
	month = jun,
	year = {2020},
	pages = {1753--1765},
}

@article{lakehal_ethylene_2020,
	title = {{ETHYLENE} {RESPONSE} {FACTOR} 115 integrates jasmonate and cytokinin signaling machineries to repress adventitious rooting in {Arabidopsis}},
	volume = {228},
	copyright = {©2020 The Authors. New Phytologist ©2020 New Phytologist Trust},
	issn = {1469-8137},
	url = {https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/nph.16794},
	doi = {10/ghhwk4},
	abstract = {Adventitious root initiation (ARI) is a de novo organogenesis program and a key adaptive trait in plants. Several hormones regulate ARI but the underlying genetic architecture that integrates the hormonal crosstalk governing this process remains largely elusive. In this study, we use genetics, genome editing, transcriptomics, hormone profiling and cell biological approaches to demonstrate a crucial role played by the APETALA2/ETHYLENE RESPONSE FACTOR 115 transcription factor. We demonstrate that ERF115 functions as a repressor of ARI by activating the cytokinin (CK) signaling machinery. We also demonstrate that ERF115 is transcriptionally activated by jasmonate (JA), an oxylipin-derived phytohormone, which represses ARI in NINJA-dependent and independent manners. Our data indicate that NINJA-dependent JA signaling in pericycle cells blocks early events of ARI. Altogether, our results reveal a previously unreported molecular network involving cooperative crosstalk between JA and CK machineries that represses ARI.},
	language = {en},
	number = {5},
	urldate = {2021-06-21},
	journal = {New Phytologist},
	author = {Lakehal, Abdellah and Dob, Asma and Rahneshan, Zahra and Novák, Ondřej and Escamez, Sacha and Alallaq, Sanaria and Strnad, Miroslav and Tuominen, Hannele and Bellini, Catherine},
	year = {2020},
	keywords = {AP2/ERF transcription factors, adventitious rooting, cytokinins, de novo organogenesis, jasmonate},
	pages = {1611--1626},
}

Adventitious root initiation (ARI) is a de novo organogenesis program and a key adaptive trait in plants. Several hormones regulate ARI but the underlying genetic architecture that integrates the hormonal crosstalk governing this process remains largely elusive. In this study, we use genetics, genome editing, transcriptomics, hormone profiling and cell biological approaches to demonstrate a crucial role played by the APETALA2/ETHYLENE RESPONSE FACTOR 115 transcription factor. We demonstrate that ERF115 functions as a repressor of ARI by activating the cytokinin (CK) signaling machinery. We also demonstrate that ERF115 is transcriptionally activated by jasmonate (JA), an oxylipin-derived phytohormone, which represses ARI in NINJA-dependent and independent manners. Our data indicate that NINJA-dependent JA signaling in pericycle cells blocks early events of ARI. Altogether, our results reveal a previously unreported molecular network involving cooperative crosstalk between JA and CK machineries that represses ARI.

@incollection{champion_multiple_2020,
	address = {New York, NY},
	title = {Multiple {Roles} of {Jasmonates} in {Shaping} {Rhizotaxis}: {Emerging} {Integrators}},
	volume = {2085},
	isbn = {978-1-07-160141-9 978-1-07-160142-6},
	shorttitle = {Multiple {Roles} of {Jasmonates} in {Shaping} {Rhizotaxis}},
	url = {http://link.springer.com/10.1007/978-1-0716-0142-6_1},
	language = {en},
	urldate = {2021-06-07},
	booktitle = {Jasmonate in {Plant} {Biology}},
	publisher = {Springer US},
	author = {Lakehal, Abdellah and Ranjan, Alok and Bellini, Catherine},
	editor = {Champion, Antony and Laplaze, Laurent},
	year = {2020},
	pages = {3--22},
}

@article{alallaq_red_2020,
	title = {Red {Light} {Controls} {Adventitious} {Root} {Regeneration} by {Modulating} {Hormone} {Homeostasis} in {Picea} abies {Seedlings}},
	volume = {11},
	issn = {1664-462X},
	url = {https://www.frontiersin.org/article/10.3389/fpls.2020.586140/full},
	doi = {10.3389/fpls.2020.586140},
	urldate = {2021-06-07},
	journal = {Frontiers in Plant Science},
	author = {Alallaq, Sanaria and Ranjan, Alok and Brunoni, Federica and Novák, Ondřej and Lakehal, Abdellah and Bellini, Catherine},
	month = sep,
	year = {2020},
	pages = {586140},
}

@article{lakehal_dao1-mediated_2019,
	title = {A {DAO1}-{Mediated} {Circuit} {Controls} {Auxin} and {Jasmonate} {Crosstalk} {Robustness} during {Adventitious} {Root} {Initiation} in {Arabidopsis}},
	volume = {20},
	issn = {1422-0067},
	url = {https://www.mdpi.com/1422-0067/20/18/4428},
	doi = {10/gjcs2h},
	abstract = {Adventitious rooting is a post-embryonic developmental program governed by a multitude of endogenous and environmental cues. Auxin, along with other phytohormones, integrates and translates these cues into precise molecular signatures to provide a coherent developmental output. Auxin signaling guides every step of adventitious root (AR) development from the early event of cell reprogramming and identity transitions until emergence. We have previously shown that auxin signaling controls the early events of AR initiation (ARI) by modulating the homeostasis of the negative regulator jasmonate (JA). Although considerable knowledge has been acquired about the role of auxin and JA in ARI, the genetic components acting downstream of JA signaling and the mechanistic basis controlling the interaction between these two hormones are not well understood. Here we provide evidence that COI1-dependent JA signaling controls the expression of DAO1 and its closely related paralog DAO2. In addition, we show that the dao1-1 loss of function mutant produces more ARs than the wild type, probably due to its deficiency in accumulating JA and its bioactive metabolite JA-Ile. Together, our data indicate that DAO1 controls a sensitive feedback circuit that stabilizes the auxin and JA crosstalk during ARI.},
	language = {en},
	number = {18},
	urldate = {2021-06-07},
	journal = {International Journal of Molecular Sciences},
	author = {Lakehal, Abdellah and Dob, Asma and Novák, Ondřej and Bellini, Catherine},
	month = sep,
	year = {2019},
	pages = {4428},
}

Adventitious rooting is a post-embryonic developmental program governed by a multitude of endogenous and environmental cues. Auxin, along with other phytohormones, integrates and translates these cues into precise molecular signatures to provide a coherent developmental output. Auxin signaling guides every step of adventitious root (AR) development from the early event of cell reprogramming and identity transitions until emergence. We have previously shown that auxin signaling controls the early events of AR initiation (ARI) by modulating the homeostasis of the negative regulator jasmonate (JA). Although considerable knowledge has been acquired about the role of auxin and JA in ARI, the genetic components acting downstream of JA signaling and the mechanistic basis controlling the interaction between these two hormones are not well understood. Here we provide evidence that COI1-dependent JA signaling controls the expression of DAO1 and its closely related paralog DAO2. In addition, we show that the dao1-1 loss of function mutant produces more ARs than the wild type, probably due to its deficiency in accumulating JA and its bioactive metabolite JA-Ile. Together, our data indicate that DAO1 controls a sensitive feedback circuit that stabilizes the auxin and JA crosstalk during ARI.

@article{lakehal_molecular_2019,
	title = {A {Molecular} {Framework} for the {Control} of {Adventitious} {Rooting} by {TIR1}/{AFB2}-{Aux}/{IAA}-{Dependent} {Auxin} {Signaling} in {Arabidopsis}},
	volume = {12},
	issn = {16742052},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S1674205219302904},
	doi = {10.1016/j.molp.2019.09.001},
	language = {en},
	number = {11},
	urldate = {2021-06-07},
	journal = {Molecular Plant},
	author = {Lakehal, Abdellah and Chaabouni, Salma and Cavel, Emilie and Le Hir, Rozenn and Ranjan, Alok and Raneshan, Zahra and Novák, Ondřej and Păcurar, Daniel I. and Perrone, Irene and Jobert, François and Gutierrez, Laurent and Bakó, Laszlo and Bellini, Catherine},
	month = nov,
	year = {2019},
	pages = {1499--1514},
}

@article{brunoni_bacterial_2019,
	title = {A bacterial assay for rapid screening of {IAA} catabolic enzymes},
	volume = {15},
	issn = {1746-4811},
	url = {https://plantmethods.biomedcentral.com/articles/10.1186/s13007-019-0509-6},
	doi = {10.1186/s13007-019-0509-6},
	abstract = {Abstract
            
              Background
              
                Plants rely on concentration gradients of the native auxin, indole-3-acetic acid (IAA), to modulate plant growth and development. Both metabolic and transport processes participate in the dynamic regulation of IAA homeostasis. Free IAA levels can be reduced by inactivation mechanisms, such as conjugation and degradation. IAA can be conjugated via ester linkage to glucose, or via amide linkage to amino acids, and degraded via oxidation. Members of the UDP glucosyl transferase (UGT) family catalyze the conversion of IAA to indole-3-acetyl-1-glucosyl ester (IAGlc); by contrast, IAA is irreversibly converted to indole-3-acetyl-
                l
                -aspartic acid (IAAsp) and indole-3-acetyl glutamic acid (IAGlu) by Group II of the GRETCHEN HAGEN3 (GH3) family of acyl amido synthetases. Dioxygenase for auxin oxidation (DAO) irreversibly oxidizes IAA to oxindole-3-acetic acid (oxIAA) and, in turn, oxIAA can be further glucosylated to oxindole-3-acetyl-1-glucosyl ester (oxIAGlc) by UGTs. These metabolic pathways have been identified based on mutant analyses, in vitro activity measurements, and
                in planta
                feeding assays. In vitro assays for studying protein activity are based on producing Arabidopsis enzymes in a recombinant form in bacteria or yeast followed by recombinant protein purification. However, the need to extract and purify the recombinant proteins represents a major obstacle when performing in vitro assays.
              
            
            
              Results
              In this work we report a rapid, reproducible and cheap method to screen the enzymatic activity of recombinant proteins that are known to inactivate IAA. The enzymatic reactions are carried out directly in bacteria that produce the recombinant protein. The enzymatic products can be measured by direct injection of a small supernatant fraction from the bacterial culture on ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UHPLC–ESI-MS/MS). Experimental procedures were optimized for testing the activity of different classes of IAA-modifying enzymes without the need to purify recombinant protein.
            
            
              Conclusions
              This new method represents an alternative to existing in vitro assays. It can be applied to the analysis of IAA metabolites that are produced upon supplementation of substrate to engineered bacterial cultures and can be used for a rapid screening of orthologous candidate genes from non-model species.},
	language = {en},
	number = {1},
	urldate = {2021-06-07},
	journal = {Plant Methods},
	author = {Brunoni, Federica and Collani, Silvio and Šimura, Jan and Schmid, Markus and Bellini, Catherine and Ljung, Karin},
	month = dec,
	year = {2019},
	pages = {126},
}

Abstract Background Plants rely on concentration gradients of the native auxin, indole-3-acetic acid (IAA), to modulate plant growth and development. Both metabolic and transport processes participate in the dynamic regulation of IAA homeostasis. Free IAA levels can be reduced by inactivation mechanisms, such as conjugation and degradation. IAA can be conjugated via ester linkage to glucose, or via amide linkage to amino acids, and degraded via oxidation. Members of the UDP glucosyl transferase (UGT) family catalyze the conversion of IAA to indole-3-acetyl-1-glucosyl ester (IAGlc); by contrast, IAA is irreversibly converted to indole-3-acetyl- l -aspartic acid (IAAsp) and indole-3-acetyl glutamic acid (IAGlu) by Group II of the GRETCHEN HAGEN3 (GH3) family of acyl amido synthetases. Dioxygenase for auxin oxidation (DAO) irreversibly oxidizes IAA to oxindole-3-acetic acid (oxIAA) and, in turn, oxIAA can be further glucosylated to oxindole-3-acetyl-1-glucosyl ester (oxIAGlc) by UGTs. These metabolic pathways have been identified based on mutant analyses, in vitro activity measurements, and in planta feeding assays. In vitro assays for studying protein activity are based on producing Arabidopsis enzymes in a recombinant form in bacteria or yeast followed by recombinant protein purification. However, the need to extract and purify the recombinant proteins represents a major obstacle when performing in vitro assays. Results In this work we report a rapid, reproducible and cheap method to screen the enzymatic activity of recombinant proteins that are known to inactivate IAA. The enzymatic reactions are carried out directly in bacteria that produce the recombinant protein. The enzymatic products can be measured by direct injection of a small supernatant fraction from the bacterial culture on ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UHPLC–ESI-MS/MS). Experimental procedures were optimized for testing the activity of different classes of IAA-modifying enzymes without the need to purify recombinant protein. Conclusions This new method represents an alternative to existing in vitro assays. It can be applied to the analysis of IAA metabolites that are produced upon supplementation of substrate to engineered bacterial cultures and can be used for a rapid screening of orthologous candidate genes from non-model species.

@article{lakehal_control_2019,
	title = {Control of adventitious root formation: insights into synergistic and antagonistic hormonal interactions},
	volume = {165},
	issn = {00319317},
	shorttitle = {Control of adventitious root formation},
	url = {http://doi.wiley.com/10.1111/ppl.12823},
	doi = {10.1111/ppl.12823},
	language = {en},
	number = {1},
	urldate = {2021-06-07},
	journal = {Physiologia Plantarum},
	author = {Lakehal, Abdellah and Bellini, Catherine},
	month = jan,
	year = {2019},
	pages = {90--100},
}

@article{brunoni_control_2019,
	title = {Control of root meristem establishment in conifers},
	volume = {165},
	issn = {00319317},
	url = {http://doi.wiley.com/10.1111/ppl.12783},
	doi = {10.1111/ppl.12783},
	language = {en},
	number = {1},
	urldate = {2021-06-07},
	journal = {Physiologia Plantarum},
	author = {Brunoni, Federica and Ljung, Karin and Bellini, Catherine},
	month = jan,
	year = {2019},
	pages = {81--89},
}

@article{aubry_lateral_2019,
	title = {Lateral {Transport} of {Organic} and {Inorganic} {Solutes}},
	volume = {8},
	issn = {2223-7747},
	url = {http://www.mdpi.com/2223-7747/8/1/20},
	doi = {10/gjdwmf},
	abstract = {Organic (e.g., sugars and amino acids) and inorganic (e.g., K+, Na+, PO42−, and SO42−) solutes are transported long-distance throughout plants. Lateral movement of these compounds between the xylem and the phloem, and vice versa, has also been reported in several plant species since the 1930s, and is believed to be important in the overall resource allocation. Studies of Arabidopsis thaliana have provided us with a better knowledge of the anatomical framework in which the lateral transport takes place, and have highlighted the role of specialized vascular and perivascular cells as an interface for solute exchanges. Important breakthroughs have also been made, mainly in Arabidopsis, in identifying some of the proteins involved in the cell-to-cell translocation of solutes, most notably a range of plasma membrane transporters that act in different cell types. Finally, in the future, state-of-art imaging techniques should help to better characterize the lateral transport of these compounds on a cellular level. This review brings the lateral transport of sugars and inorganic solutes back into focus and highlights its importance in terms of our overall understanding of plant resource allocation.},
	language = {en},
	number = {1},
	urldate = {2021-06-07},
	journal = {Plants},
	author = {Aubry, Emilie and Dinant, Sylvie and Vilaine, Françoise and Bellini, Catherine and Le Hir, Rozenn},
	month = jan,
	year = {2019},
	pages = {20},
}

Organic (e.g., sugars and amino acids) and inorganic (e.g., K+, Na+, PO42−, and SO42−) solutes are transported long-distance throughout plants. Lateral movement of these compounds between the xylem and the phloem, and vice versa, has also been reported in several plant species since the 1930s, and is believed to be important in the overall resource allocation. Studies of Arabidopsis thaliana have provided us with a better knowledge of the anatomical framework in which the lateral transport takes place, and have highlighted the role of specialized vascular and perivascular cells as an interface for solute exchanges. Important breakthroughs have also been made, mainly in Arabidopsis, in identifying some of the proteins involved in the cell-to-cell translocation of solutes, most notably a range of plasma membrane transporters that act in different cell types. Finally, in the future, state-of-art imaging techniques should help to better characterize the lateral transport of these compounds on a cellular level. This review brings the lateral transport of sugars and inorganic solutes back into focus and highlights its importance in terms of our overall understanding of plant resource allocation.

@article{dinant_synchrotron_2019,
	title = {Synchrotron {FTIR} and {Raman} spectroscopy provide unique spectral fingerprints for {Arabidopsis} floral stem vascular tissues},
	volume = {70},
	issn = {0022-0957, 1460-2431},
	url = {https://academic.oup.com/jxb/article/70/3/871/5165365},
	doi = {10.1093/jxb/ery396},
	language = {en},
	number = {3},
	urldate = {2021-06-07},
	journal = {Journal of Experimental Botany},
	author = {Dinant, S and Wolff, N and De Marco, F and Vilaine, F and Gissot, L and Aubry, E and Sandt, C and Bellini, C. and Le Hir, R},
	month = feb,
	year = {2019},
	pages = {871--884},
}

@incollection{geiss_adventitious_2018,
	title = {Adventitious {Root} {Formation}: {New} {Insights} and {Perspectives}},
	copyright = {Copyright © 2010 by Blackwell Publishing Ltd},
	isbn = {978-1-119-31299-4},
	shorttitle = {Adventitious {Root} {Formation}},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119312994.apr0400},
	abstract = {The root system of a plant consists of the primary, lateral and adventitious roots. Lateral roots always develop from roots whereas adventitious roots form from stem or leaf-derived cells. Adventitious rooting is an essential step in the vegetative propagation of economically important horticultural and woody species. It allows clonal propagation and rapid fixation of superior genotypes prior to their introduction into production or breeding programs. Problems associated with rooting of cuttings frequently result in significant economic losses. Development of adventitious roots is a complex process that is affected by multiple factors including phytohormones, light, nutritional status, associated stress responses such as wounding, and genetic characteristics. How endogenous and environmental factors interact to control adventitious root formation is still poorly understood, although significant progress has been made in the understanding of the molecular control of root and lateral root development. In this review, we will summarize the current knowledge on the physiological aspects of AR formation and highlight the recent progress made in the identification of putative molecular players involved in the control of adventitious rooting.},
	language = {en},
	urldate = {2024-10-07},
	booktitle = {Annual {Plant} {Reviews} online},
	publisher = {John Wiley \& Sons, Ltd},
	author = {Geiss, Gaia and Gutierrez, Laurent and Bellini, Catherine},
	year = {2018},
	doi = {10.1002/9781119312994.apr0400},
	note = {Section: 5
\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781119312994.apr0400},
	keywords = {adventitious roots, clonal propagation, light, molecular markers, phyto-hormones, quantitative trait},
	pages = {127--156},
}

The root system of a plant consists of the primary, lateral and adventitious roots. Lateral roots always develop from roots whereas adventitious roots form from stem or leaf-derived cells. Adventitious rooting is an essential step in the vegetative propagation of economically important horticultural and woody species. It allows clonal propagation and rapid fixation of superior genotypes prior to their introduction into production or breeding programs. Problems associated with rooting of cuttings frequently result in significant economic losses. Development of adventitious roots is a complex process that is affected by multiple factors including phytohormones, light, nutritional status, associated stress responses such as wounding, and genetic characteristics. How endogenous and environmental factors interact to control adventitious root formation is still poorly understood, although significant progress has been made in the understanding of the molecular control of root and lateral root development. In this review, we will summarize the current knowledge on the physiological aspects of AR formation and highlight the recent progress made in the identification of putative molecular players involved in the control of adventitious rooting.

@article{rahneshan_unravelling_2018,
	title = {Unravelling salt stress responses in two pistachio ({Pistacia} vera {L}.) genotypes},
	volume = {40},
	issn = {0137-5881, 1861-1664},
	url = {http://link.springer.com/10.1007/s11738-018-2745-1},
	doi = {10.1007/s11738-018-2745-1},
	language = {en},
	number = {9},
	urldate = {2021-06-07},
	journal = {Acta Physiologiae Plantarum},
	author = {Rahneshan, Zahra and Nasibi, Fatemeh and Lakehal, Abdellah and Bellini, Catherine},
	month = sep,
	year = {2018},
	pages = {172},
}

@article{le_hir_at_2017,
	title = {At \textit{{bHLH68}} transcription factor contributes to the regulation of {ABA} homeostasis and drought stress tolerance in \textit{{Arabidopsis} thaliana}},
	volume = {160},
	issn = {00319317},
	url = {http://doi.wiley.com/10.1111/ppl.12549},
	doi = {10.1111/ppl.12549},
	language = {en},
	number = {3},
	urldate = {2021-06-07},
	journal = {Physiologia Plantarum},
	author = {Le Hir, Rozenn and Castelain, Mathieu and Chakraborti, Dipankar and Moritz, Thomas and Dinant, Sylvie and Bellini, Catherine},
	month = jul,
	year = {2017},
	pages = {312--327},
}

@article{pacurar_arabidopsis_2017,
	title = {The {Arabidopsis} {Cop9} signalosome subunit 4 ({CSN4}) is involved in adventitious root formation},
	volume = {7},
	issn = {2045-2322},
	url = {http://www.nature.com/articles/s41598-017-00744-1},
	doi = {10.1038/s41598-017-00744-1},
	language = {en},
	number = {1},
	urldate = {2021-06-07},
	journal = {Scientific Reports},
	author = {Pacurar, Daniel Ioan and Pacurar, Monica Lacramioara and Lakehal, Abdellah and Pacurar, Andrea Mariana and Ranjan, Alok and Bellini, Catherine},
	month = dec,
	year = {2017},
	pages = {628},
}

@article{le_hir_disruption_2015,
	title = {Disruption of the {Sugar} {Transporters} {AtSWEET11} and {AtSWEET12} {Affects} {Vascular} {Development} and {Freezing} {Tolerance} in {Arabidopsis}},
	volume = {8},
	issn = {1752-9867 (Electronic) 1674-2052 (Linking)},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/26358680},
	doi = {10.1016/j.molp.2015.08.007},
	language = {en},
	number = {11},
	urldate = {2021-06-07},
	journal = {Mol Plant},
	author = {Le Hir, R. and Spinner, L. and Klemens, P. A. and Chakraborti, D. and de Marco, F. and Vilaine, F. and Wolff, N. and Lemoine, R. and Porcheron, B. and Gery, C. and Teoule, E. and Chabout, S. and Mouille, G. and Neuhaus, H. E. and Dinant, S. and Bellini, C.},
	month = nov,
	year = {2015},
	note = {Edition: 2015/09/12},
	keywords = {Adaptation, Physiological, Arabidopsis Proteins/genetics/*physiology, Arabidopsis/growth \& development/metabolism/*physiology, Carbohydrates, Cell Wall/metabolism, Freezing, Membrane Transport Proteins/genetics/*physiology, Phloem/metabolism, Xylem/metabolism},
	pages = {1687--90},
}

@article{pacurar_novel_2014,
	title = {A {Novel} {Viable} {Allele} of {Arabidopsis} {CULLIN1} {Identified} in a {Screen} for {Superroot2} {Suppressors} by {Next} {Generation} {Sequencing}-{Assisted} {Mapping}},
	volume = {9},
	issn = {1932-6203},
	url = {https://dx.plos.org/10.1371/journal.pone.0100846},
	doi = {10/f22p63},
	language = {en},
	number = {6},
	urldate = {2021-06-08},
	journal = {PLoS ONE},
	author = {Pacurar, Daniel I. and Pacurar, Monica L. and Pacurar, Andrea M. and Gutierrez, Laurent and Bellini, Catherine},
	editor = {Zwick, Michael Edward.},
	month = jun,
	year = {2014},
	pages = {e100846},
}

@incollection{bellini_adventitious_2014,
	title = {Adventitious {Roots}},
	copyright = {Copyright © 2014 John Wiley \& Sons, Ltd. All rights reserved.},
	isbn = {978-0-470-01590-2},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/9780470015902.a0002061.pub2},
	abstract = {The root system of a plant is composed of the primary, lateral and adventitious roots (ARs). Lateral roots always develop from roots, whereas ARs form from stem or leaf-derived cells. AR formation is part of the normal development of the plant and occurs naturally, like in most monocotyledonous for which they constitute the main root system or in many dicotyledonous species that propagate vegetatively. Adventitious rooting is an essential step for vegetative propagation of economically important horticultural and woody species as it allows clonal propagation and rapid fixation of superior genotypes prior to their introduction into production or breeding programmes. Development of ARs is a complex process that is affected by multiple endogenous and environmental factors, including phytohormones; light; nutritional status; associated stress responses, such as wounding; and genetic characteristics. Key Concepts: ARs are the main root system for monocots. ARs are an adaptative response to environmental changes. ARs are required for vegetative propagation of plants. ARs arise from any organ of the plant but the root. ARs originate from different cell types depending on the organ or the species. ARs can be induced by ECMs or Agrobacterium rhizogenes. ARdevelopment is controlled by environmental factors. Adventitious rooting is an age-dependant process. Auxin cross talks with other hormones to control adventitious rooting. Adventitious rooting is a complex quantitative genetic trait.},
	language = {en},
	urldate = {2024-10-07},
	booktitle = {{eLS}},
	publisher = {John Wiley \& Sons, Ltd},
	author = {Bellini, Catherine},
	year = {2014},
	doi = {10.1002/9780470015902.a0002061.pub2},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/9780470015902.a0002061.pub2},
	keywords = {abiotic factors, adventitious roots, biotic factors, plant hormones, vegetative propagation},
}

The root system of a plant is composed of the primary, lateral and adventitious roots (ARs). Lateral roots always develop from roots, whereas ARs form from stem or leaf-derived cells. AR formation is part of the normal development of the plant and occurs naturally, like in most monocotyledonous for which they constitute the main root system or in many dicotyledonous species that propagate vegetatively. Adventitious rooting is an essential step for vegetative propagation of economically important horticultural and woody species as it allows clonal propagation and rapid fixation of superior genotypes prior to their introduction into production or breeding programmes. Development of ARs is a complex process that is affected by multiple endogenous and environmental factors, including phytohormones; light; nutritional status; associated stress responses, such as wounding; and genetic characteristics. Key Concepts: ARs are the main root system for monocots. ARs are an adaptative response to environmental changes. ARs are required for vegetative propagation of plants. ARs arise from any organ of the plant but the root. ARs originate from different cell types depending on the organ or the species. ARs can be induced by ECMs or Agrobacterium rhizogenes. ARdevelopment is controlled by environmental factors. Adventitious rooting is an age-dependant process. Auxin cross talks with other hormones to control adventitious rooting. Adventitious rooting is a complex quantitative genetic trait.

@article{bellini_adventitious_2014,
	title = {Adventitious {Roots} and {Lateral} {Roots}: {Similarities} and {Differences}},
	volume = {65},
	issn = {1543-5008, 1545-2123},
	shorttitle = {Adventitious {Roots} and {Lateral} {Roots}},
	url = {http://www.annualreviews.org/doi/10.1146/annurev-arplant-050213-035645},
	doi = {10/f2z6rb},
	language = {en},
	number = {1},
	urldate = {2021-06-08},
	journal = {Annual Review of Plant Biology},
	author = {Bellini, Catherine and Pacurar, Daniel I. and Perrone, Irene},
	month = apr,
	year = {2014},
	pages = {639--666},
}

@article{pacurar_auxin_2014,
	title = {Auxin is a central player in the hormone cross-talks that control adventitious rooting},
	volume = {151},
	issn = {00319317},
	url = {http://doi.wiley.com/10.1111/ppl.12171},
	doi = {10/f2264z},
	language = {en},
	number = {1},
	urldate = {2021-06-08},
	journal = {Physiologia Plantarum},
	author = {Pacurar, Daniel Ioan and Perrone, Irene and Bellini, Catherine},
	month = may,
	year = {2014},
	pages = {83--96},
}

@article{mauriat_gibberellins_2014,
	title = {Gibberellins inhibit adventitious rooting in hybrid aspen and {Arabidopsis} by affecting auxin transport},
	volume = {78},
	issn = {09607412},
	url = {http://doi.wiley.com/10.1111/tpj.12478},
	doi = {10/f22tk3},
	language = {en},
	number = {3},
	urldate = {2021-06-08},
	journal = {The Plant Journal},
	author = {Mauriat, Mélanie and Petterle, Anna and Bellini, Catherine and Moritz, Thomas},
	month = may,
	year = {2014},
	pages = {372--384},
}

@article{pacurar_identification_2014,
	title = {Identification of new adventitious rooting mutants amongst suppressors of the {Arabidopsis} thaliana superroot2 mutation},
	volume = {65},
	issn = {0022-0957},
	url = {https://doi.org/10.1093/jxb/eru026},
	doi = {10/f23rss},
	abstract = {The plant hormone auxin plays a central role in adventitious rooting and is routinely used with many economically important, vegetatively propagated plant species to promote adventitious root initiation and development on cuttings. Nevertheless the molecular mechanisms through which it acts are only starting to emerge. The Arabidopsis superroot2-1 (sur2-1) mutant overproduces auxin and, as a consequence, develops excessive adventitious roots in the hypocotyl. In order to increase the knowledge of adventitious rooting and of auxin signalling pathways and crosstalk, this study performed a screen for suppressors of superroot2-1 phenotype. These suppressors provide a new resource for discovery of genetic players involved in auxin signalling pathways or at the crosstalk of auxin and other hormones or environmental signals. This study reports the identification and characterization of 26 sur2-1 suppressor mutants, several of which were identified as mutations in candidate genes involved in either auxin biosynthesis or signalling. In addition to confirming the role of auxin as a central regulator of adventitious rooting, superroot2 suppressors indicated possible crosstalk with ethylene signalling in this process.},
	number = {6},
	urldate = {2021-06-08},
	journal = {Journal of Experimental Botany},
	author = {Pacurar, Daniel Ioan and Pacurar, Monica Lacramioara and Bussell, John Desmond and Schwambach, Joseli and Pop, Tiberia Ioana and Kowalczyk, Mariusz and Gutierrez, Laurent and Cavel, Emilie and Chaabouni, Salma and Ljung, Karin and Fett-Neto, Arthur Germano and Pamfil, Doru and Bellini, Catherine},
	month = apr,
	year = {2014},
	pages = {1605--1618},
}

The plant hormone auxin plays a central role in adventitious rooting and is routinely used with many economically important, vegetatively propagated plant species to promote adventitious root initiation and development on cuttings. Nevertheless the molecular mechanisms through which it acts are only starting to emerge. The Arabidopsis superroot2-1 (sur2-1) mutant overproduces auxin and, as a consequence, develops excessive adventitious roots in the hypocotyl. In order to increase the knowledge of adventitious rooting and of auxin signalling pathways and crosstalk, this study performed a screen for suppressors of superroot2-1 phenotype. These suppressors provide a new resource for discovery of genetic players involved in auxin signalling pathways or at the crosstalk of auxin and other hormones or environmental signals. This study reports the identification and characterization of 26 sur2-1 suppressor mutants, several of which were identified as mutations in candidate genes involved in either auxin biosynthesis or signalling. In addition to confirming the role of auxin as a central regulator of adventitious rooting, superroot2 suppressors indicated possible crosstalk with ethylene signalling in this process.

@article{le_hir_abcg9_2013,
	title = {{ABCG9}, {ABCG11} and {ABCG14} {ABC} transporters are required for vascular development in {Arabidopsis}},
	volume = {76},
	issn = {09607412},
	url = {http://doi.wiley.com/10.1111/tpj.12334},
	doi = {10/f22xd4},
	language = {en},
	number = {5},
	urldate = {2021-06-08},
	journal = {The Plant Journal},
	author = {Le Hir, Rozenn and Sorin, Clément and Chakraborti, Dipankar and Moritz, Thomas and Schaller, Hubert and Tellier, Frédérique and Robert, Stéphanie and Morin, Halima and Bakó, Laszlo and Bellini, Catherine},
	month = dec,
	year = {2013},
	pages = {811--824},
}

@article{chardon_leaf_2013,
	title = {Leaf {Fructose} {Content} {Is} {Controlled} by the {Vacuolar} {Transporter} {SWEET17} in {Arabidopsis}},
	volume = {23},
	issn = {09609822},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S096098221300287X},
	doi = {10/f24bg2},
	language = {en},
	number = {8},
	urldate = {2021-06-08},
	journal = {Current Biology},
	author = {Chardon, Fabien and Bedu, Magali and Calenge, Fanny and Klemens, Patrick A.W. and Spinner, Lara and Clement, Gilles and Chietera, Giorgiana and Léran, Sophie and Ferrand, Marina and Lacombe, Benoit and Loudet, Olivier and Dinant, Sylvie and Bellini, Catherine and Neuhaus, H. Ekkehard and Daniel-Vedele, Françoise and Krapp, Anne},
	month = apr,
	year = {2013},
	pages = {697--702},
}

@article{klemens_overexpression_2013,
	title = {Overexpression of the {Vacuolar} {Sugar} {Carrier} \textit{{AtSWEET16}} {Modifies} {Germination}, {Growth}, and {Stress} {Tolerance} in {Arabidopsis}},
	volume = {163},
	issn = {1532-2548},
	url = {https://academic.oup.com/plphys/article/163/3/1338/6112737},
	doi = {10/f23t2h},
	abstract = {Abstract
            Here, we report that SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTER (SWEET16) from Arabidopsis (Arabidopsis thaliana) is a vacuole-located carrier, transporting glucose (Glc), fructose (Fru), and sucrose (Suc) after heterologous expression in Xenopus laevis oocytes. The SWEET16 gene, similar to the homologs gene SWEET17, is mainly expressed in vascular parenchyma cells. Application of Glc, Fru, or Suc, as well as cold, osmotic stress, or low nitrogen, provoke the down-regulation of SWEET16 messenger RNA accumulation. SWEET16 overexpressors (35SPro:SWEET16) showed a number of peculiarities related to differences in sugar accumulation, such as less Glc, Fru, and Suc at the end of the night. Under cold stress, 35SPro:SWEET16 plants are unable to accumulate Fru, while under nitrogen starvation, both Glc and Fru, but not Suc, were less abundant. These changes of individual sugars indicate that the consequences of an increased SWEET16 activity are dependent upon the type of external stimulus. Remarkably, 35SPro:SWEET16 lines showed improved germination and increased freezing tolerance. The latter observation, in combination with the modified sugar levels, points to a superior function of Glc and Suc for frost tolerance. 35SPro:SWEET16 plants exhibited increased growth efficiency when cultivated on soil and showed improved nitrogen use efficiency when nitrate was sufficiently available, while under conditions of limiting nitrogen, wild-type biomasses were higher than those of 35SPro:SWEET16 plants. Our results identify SWEET16 as a vacuolar sugar facilitator, demonstrate the substantial impact of SWEET16 overexpression on various critical plant traits, and imply that SWEET16 activity must be tightly regulated to allow optimal Arabidopsis development under nonfavorable conditions.},
	language = {en},
	number = {3},
	urldate = {2021-06-08},
	journal = {Plant Physiology},
	author = {Klemens, Patrick A.W. and Patzke, Kathrin and Deitmer, Joachim and Spinner, Lara and Le Hir, Rozenn and Bellini, Catherine and Bedu, Magali and Chardon, Fabien and Krapp, Anne and Neuhaus, H. Ekkehard},
	month = oct,
	year = {2013},
	pages = {1338--1352},
}

Abstract Here, we report that SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTER (SWEET16) from Arabidopsis (Arabidopsis thaliana) is a vacuole-located carrier, transporting glucose (Glc), fructose (Fru), and sucrose (Suc) after heterologous expression in Xenopus laevis oocytes. The SWEET16 gene, similar to the homologs gene SWEET17, is mainly expressed in vascular parenchyma cells. Application of Glc, Fru, or Suc, as well as cold, osmotic stress, or low nitrogen, provoke the down-regulation of SWEET16 messenger RNA accumulation. SWEET16 overexpressors (35SPro:SWEET16) showed a number of peculiarities related to differences in sugar accumulation, such as less Glc, Fru, and Suc at the end of the night. Under cold stress, 35SPro:SWEET16 plants are unable to accumulate Fru, while under nitrogen starvation, both Glc and Fru, but not Suc, were less abundant. These changes of individual sugars indicate that the consequences of an increased SWEET16 activity are dependent upon the type of external stimulus. Remarkably, 35SPro:SWEET16 lines showed improved germination and increased freezing tolerance. The latter observation, in combination with the modified sugar levels, points to a superior function of Glc and Suc for frost tolerance. 35SPro:SWEET16 plants exhibited increased growth efficiency when cultivated on soil and showed improved nitrogen use efficiency when nitrate was sufficiently available, while under conditions of limiting nitrogen, wild-type biomasses were higher than those of 35SPro:SWEET16 plants. Our results identify SWEET16 as a vacuolar sugar facilitator, demonstrate the substantial impact of SWEET16 overexpression on various critical plant traits, and imply that SWEET16 activity must be tightly regulated to allow optimal Arabidopsis development under nonfavorable conditions.

@article{le_hir_plant-specific_2013,
	title = {The {Plant}-{Specific} {Dof} {Transcription} {Factors} {Family}: {New} {Players} {Involved} in {Vascular} {System} {Development} and {Functioning} in {Arabidopsis}},
	volume = {4},
	issn = {1664-462X},
	shorttitle = {The {Plant}-{Specific} {Dof} {Transcription} {Factors} {Family}},
	url = {http://journal.frontiersin.org/article/10.3389/fpls.2013.00164/abstract},
	doi = {10/f2ztrr},
	urldate = {2021-06-08},
	journal = {Frontiers in Plant Science},
	author = {Le Hir, Rozenn and Bellini, Catherine},
	year = {2013},
}

@article{pacurar_collection_2012,
	title = {A collection of {INDEL} markers for map-based cloning in seven {Arabidopsis} accessions},
	volume = {63},
	issn = {1460-2431, 0022-0957},
	url = {https://academic.oup.com/jxb/article-lookup/doi/10.1093/jxb/err422},
	doi = {10/fxrh28},
	language = {en},
	number = {7},
	urldate = {2021-06-08},
	journal = {Journal of Experimental Botany},
	author = {Păcurar, Daniel Ioan and Păcurar, Monica Lăcrămioara and Street, Nathaniel and Bussell, John Desmond and Pop, Tiberia Ioana and Gutierrez, Laurent and Bellini, Catherine},
	month = apr,
	year = {2012},
	pages = {2491--2501},
}

@article{gutierrez_auxin_2012,
	title = {Auxin {Controls} {Arabidopsis} {Adventitious} {Root} {Initiation} by {Regulating} {Jasmonic} {Acid} {Homeostasis}},
	volume = {24},
	issn = {1040-4651},
	url = {https://doi.org/10.1105/tpc.112.099119},
	doi = {10/f22j9d},
	abstract = {Vegetative shoot-based propagation of plants, including mass propagation of elite genotypes, is dependent on the development of shoot-borne roots, which are also called adventitious roots. Multiple endogenous and environmental factors control the complex process of adventitious rooting. In the past few years, we have shown that the auxin response factors ARF6 and ARF8, targets of the microRNA miR167, are positive regulators of adventitious rooting, whereas ARF17, a target of miR160, is a negative regulator. We showed that these genes have overlapping expression profiles during adventitious rooting and that they regulate each other's expression at the transcriptional and posttranscriptional levels by modulating the homeostasis of miR160 and miR167. We demonstrate here that this complex network of transcription factors regulates the expression of three auxin-inducible Gretchen Hagen3 (GH3) genes, GH3.3, GH3.5, and GH3.6, encoding acyl-acid-amido synthetases. We show that these three GH3 genes are required for fine-tuning adventitious root initiation in the Arabidopsis thaliana hypocotyl, and we demonstrate that they act by modulating jasmonic acid homeostasis. We propose a model in which adventitious rooting is an adaptive developmental response involving crosstalk between the auxin and jasmonate regulatory pathways.},
	number = {6},
	urldate = {2021-06-08},
	journal = {The Plant Cell},
	author = {Gutierrez, Laurent and Mongelard, Gaëlle and Floková, Kristýna and Păcurar, Daniel I. and Novák, Ondřej and Staswick, Paul and Kowalczyk, Mariusz and Păcurar, Monica and Demailly, Hervé and Geiss, Gaia and Bellini, Catherine},
	month = jun,
	year = {2012},
	pages = {2515--2527},
}

Vegetative shoot-based propagation of plants, including mass propagation of elite genotypes, is dependent on the development of shoot-borne roots, which are also called adventitious roots. Multiple endogenous and environmental factors control the complex process of adventitious rooting. In the past few years, we have shown that the auxin response factors ARF6 and ARF8, targets of the microRNA miR167, are positive regulators of adventitious rooting, whereas ARF17, a target of miR160, is a negative regulator. We showed that these genes have overlapping expression profiles during adventitious rooting and that they regulate each other's expression at the transcriptional and posttranscriptional levels by modulating the homeostasis of miR160 and miR167. We demonstrate here that this complex network of transcription factors regulates the expression of three auxin-inducible Gretchen Hagen3 (GH3) genes, GH3.3, GH3.5, and GH3.6, encoding acyl-acid-amido synthetases. We show that these three GH3 genes are required for fine-tuning adventitious root initiation in the Arabidopsis thaliana hypocotyl, and we demonstrate that they act by modulating jasmonic acid homeostasis. We propose a model in which adventitious rooting is an adaptive developmental response involving crosstalk between the auxin and jasmonate regulatory pathways.

@article{rigal_aintegumenta_2012,
	title = {The {AINTEGUMENTA} {LIKE1} homeotic transcription factor {PtAIL1} controls the formation of adventitious root primordia in poplar},
	volume = {160},
	issn = {1532-2548},
	doi = {10/f2ztb6},
	abstract = {Adventitious rooting is an essential but sometimes rate-limiting step in the clonal multiplication of elite tree germplasm, because the ability to form roots declines rapidly with age in mature adult plant tissues. In spite of the importance of adventitious rooting, the mechanism behind this developmental process remains poorly understood. We have described the transcriptional profiles that are associated with the developmental stages of adventitious root formation in the model tree poplar (Populus trichocarpa). Transcriptome analyses indicate a highly specific temporal induction of the AINTEGUMENTA LIKE1 (PtAIL1) transcription factor of the AP2 family during adventitious root formation. Transgenic poplar samples that overexpressed PtAIL1 were able to grow an increased number of adventitious roots, whereas RNA interference mediated the down-expression of PtAIL1 expression, which led to a delay in adventitious root formation. Microarray analysis showed that the expression of 15 genes, including the transcription factors AGAMOUS-Like6 and MYB36, was overexpressed in the stem tissues that generated root primordia in PtAIL1-overexpressing plants, whereas their expression was reduced in the RNA interference lines. These results demonstrate that PtAIL1 is a positive regulator of poplar rooting that acts early in the development of adventitious roots.},
	language = {eng},
	number = {4},
	journal = {Plant Physiology},
	author = {Rigal, Adeline and Yordanov, Yordan S. and Perrone, Irene and Karlberg, Anna and Tisserant, Emilie and Bellini, Catherine and Busov, Victor B. and Martin, Francis and Kohler, Annegret and Bhalerao, Rishikesh P. and Legué, Valérie},
	month = dec,
	year = {2012},
	pmid = {23077242},
	pmcid = {PMC3510126},
	keywords = {Gene Expression Regulation, Developmental, Gene Expression Regulation, Plant, Genes, Homeobox, Plant Proteins, Plant Roots, Plants, Genetically Modified, Populus, RNA Interference, RNA, Messenger, Transcription Factors, Transcriptome},
	pages = {1996--2006},
}

Adventitious rooting is an essential but sometimes rate-limiting step in the clonal multiplication of elite tree germplasm, because the ability to form roots declines rapidly with age in mature adult plant tissues. In spite of the importance of adventitious rooting, the mechanism behind this developmental process remains poorly understood. We have described the transcriptional profiles that are associated with the developmental stages of adventitious root formation in the model tree poplar (Populus trichocarpa). Transcriptome analyses indicate a highly specific temporal induction of the AINTEGUMENTA LIKE1 (PtAIL1) transcription factor of the AP2 family during adventitious root formation. Transgenic poplar samples that overexpressed PtAIL1 were able to grow an increased number of adventitious roots, whereas RNA interference mediated the down-expression of PtAIL1 expression, which led to a delay in adventitious root formation. Microarray analysis showed that the expression of 15 genes, including the transcription factors AGAMOUS-Like6 and MYB36, was overexpressed in the stem tissues that generated root primordia in PtAIL1-overexpressing plants, whereas their expression was reduced in the RNA interference lines. These results demonstrate that PtAIL1 is a positive regulator of poplar rooting that acts early in the development of adventitious roots.

@article{castelain_non-dna-binding_2012,
	title = {The non-{DNA}-binding {bHLH} transcription factor {PRE3}/{bHLH135}/{ATBS1}/{TMO7} is involved in the regulation of light signaling pathway in {Arabidopsis}},
	volume = {145},
	issn = {00319317},
	url = {http://doi.wiley.com/10.1111/j.1399-3054.2012.01600.x},
	doi = {10/f2z8jx},
	language = {en},
	number = {3},
	urldate = {2021-06-08},
	journal = {Physiologia Plantarum},
	author = {Castelain, Mathieu and Le Hir, Rozenn and Bellini, Catherine},
	month = jul,
	year = {2012},
	pages = {450--460},
}

@article{pacurar_agrobacterium_2011,
	title = {Agrobacterium tumefaciens: {From} crown gall tumors to genetic transformation},
	volume = {76},
	issn = {08855765},
	shorttitle = {Agrobacterium tumefaciens},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0885576511000580},
	doi = {10/drwscf},
	language = {en},
	number = {2},
	urldate = {2021-06-08},
	journal = {Physiological and Molecular Plant Pathology},
	author = {Păcurar, Daniel I. and Thordal-Christensen, Hans and Păcurar, Monica L. and Pamfil, Doru and Botez, Constantin and Bellini, Catherine},
	month = aug,
	year = {2011},
	pages = {76--81},
}

@article{pop_auxin_2011,
	title = {Auxin {Control} in the {Formation} of {Adventitious} {Roots}},
	volume = {39},
	doi = {10/gc8s37},
	abstract = {Adventitious rooting is a complex process and a key step in the vegetative propagation of economically important woody, horticultural and agricultural species, playing an important role in the successful production of elite clones. The formation of adventitious roots is a quantitative genetic trait regulated by both environmental and endogenous factors. Among phytohormones, auxin plays an essential role in regulating roots development and it has been shown to be intimately involved in the process of adventitious rooting. Great progress has been made in elucidating the auxin-induced genes and auxin signaling pathway, especially in auxin response Aux/IAA and Auxin Response Factor gene families. Although some important aspects of adventitious and lateral rooting signaling have been revealed, the intricate signaling network remains poorly understood. This review summarizes some of the current knowledge on the physiological aspects of adventitious root formation and highlights the recent progress made in the identification of putative molecular players involved in the control of adventitious rooting. Despite much has been discovered regarding the effects and regulation of auxins on plant growth since the Darwin experiments, there is much that remains unknown.},
	journal = {Notulae Botanicae Horti Agrobotanici Cluj-Napoca},
	author = {Pop, Tiberia and Pamfil, Doru and Bellini, Catherine},
	month = jun,
	year = {2011},
	pages = {307--316},
}

Adventitious rooting is a complex process and a key step in the vegetative propagation of economically important woody, horticultural and agricultural species, playing an important role in the successful production of elite clones. The formation of adventitious roots is a quantitative genetic trait regulated by both environmental and endogenous factors. Among phytohormones, auxin plays an essential role in regulating roots development and it has been shown to be intimately involved in the process of adventitious rooting. Great progress has been made in elucidating the auxin-induced genes and auxin signaling pathway, especially in auxin response Aux/IAA and Auxin Response Factor gene families. Although some important aspects of adventitious and lateral rooting signaling have been revealed, the intricate signaling network remains poorly understood. This review summarizes some of the current knowledge on the physiological aspects of adventitious root formation and highlights the recent progress made in the identification of putative molecular players involved in the control of adventitious rooting. Despite much has been discovered regarding the effects and regulation of auxins on plant growth since the Darwin experiments, there is much that remains unknown.

@article{keech_leaf_2010,
	title = {Leaf {Senescence} {Is} {Accompanied} by an {Early} {Disruption} of the {Microtubule} {Network} in {Arabidopsis}},
	volume = {154},
	issn = {1532-2548},
	url = {https://academic.oup.com/plphys/article/154/4/1710/6108651},
	doi = {10/cp2qs5},
	abstract = {Abstract
            The dynamic assembly and disassembly of microtubules (MTs) is essential for cell function. Although leaf senescence is a well-documented process, the role of the MT cytoskeleton during senescence in plants remains unknown. Here, we show that both natural leaf senescence and senescence of individually darkened Arabidopsis (Arabidopsis thaliana) leaves are accompanied by early degradation of the MT network in epidermis and mesophyll cells, whereas guard cells, which do not senesce, retain their MT network. Similarly, entirely darkened plants, which do not senesce, retain their MT network. While genes encoding the tubulin subunits and the bundling/stabilizing MT-associated proteins (MAPs) MAP65 and MAP70-1 were repressed in both natural senescence and dark-induced senescence, we found strong induction of the gene encoding the MT-destabilizing protein MAP18. However, induction of MAP18 gene expression was also observed in leaves from entirely darkened plants, showing that its expression is not sufficient to induce MT disassembly and is more likely to be part of a Ca2+-dependent signaling mechanism. Similarly, genes encoding the MT-severing protein katanin p60 and two of the four putative regulatory katanin p80s were repressed in the dark, but their expression did not correlate with degradation of the MT network during leaf senescence. Taken together, these results highlight the earliness of the degradation of the cortical MT array during leaf senescence and lead us to propose a model in which suppression of tubulin and MAP genes together with induction of MAP18 play key roles in MT disassembly during senescence.},
	language = {en},
	number = {4},
	urldate = {2021-06-08},
	journal = {Plant Physiology},
	author = {Keech, Olivier and Pesquet, Edouard and Gutierrez, Laurent and Ahad, Abdul and Bellini, Catherine and Smith, Steven M. and Gardeström, Per},
	month = dec,
	year = {2010},
	pages = {1710--1720},
}

Abstract The dynamic assembly and disassembly of microtubules (MTs) is essential for cell function. Although leaf senescence is a well-documented process, the role of the MT cytoskeleton during senescence in plants remains unknown. Here, we show that both natural leaf senescence and senescence of individually darkened Arabidopsis (Arabidopsis thaliana) leaves are accompanied by early degradation of the MT network in epidermis and mesophyll cells, whereas guard cells, which do not senesce, retain their MT network. Similarly, entirely darkened plants, which do not senesce, retain their MT network. While genes encoding the tubulin subunits and the bundling/stabilizing MT-associated proteins (MAPs) MAP65 and MAP70-1 were repressed in both natural senescence and dark-induced senescence, we found strong induction of the gene encoding the MT-destabilizing protein MAP18. However, induction of MAP18 gene expression was also observed in leaves from entirely darkened plants, showing that its expression is not sufficient to induce MT disassembly and is more likely to be part of a Ca2+-dependent signaling mechanism. Similarly, genes encoding the MT-severing protein katanin p60 and two of the four putative regulatory katanin p80s were repressed in the dark, but their expression did not correlate with degradation of the MT network during leaf senescence. Taken together, these results highlight the earliness of the degradation of the cortical MT array during leaf senescence and lead us to propose a model in which suppression of tubulin and MAP genes together with induction of MAP18 play key roles in MT disassembly during senescence.

@article{contesto_auxin-signaling_2010,
	title = {The auxin-signaling pathway is required for the lateral root response of {Arabidopsis} to the rhizobacterium {Phyllobacterium} brassicacearum},
	volume = {232},
	issn = {0032-0935, 1432-2048},
	url = {http://link.springer.com/10.1007/s00425-010-1264-0},
	doi = {10/c99m2s},
	language = {en},
	number = {6},
	urldate = {2021-06-08},
	journal = {Planta},
	author = {Contesto, Céline and Milesi, Sandrine and Mantelin, Sophie and Zancarini, Anouk and Desbrosses, Guilhem and Varoquaux, Fabrice and Bellini, Catherine and Kowalczyk, Mariusz and Touraine, Bruno},
	month = nov,
	year = {2010},
	pages = {1455--1470},
}

@article{guenin_normalization_2009,
	title = {Normalization of {qRT}-{PCR} data: the necessity of adopting a systematic, experimental conditions-specific, validation of references},
	volume = {60},
	issn = {0022-0957, 1460-2431},
	shorttitle = {Normalization of {qRT}-{PCR} data},
	url = {https://academic.oup.com/jxb/article-lookup/doi/10.1093/jxb/ern305},
	doi = {10/bf946c},
	language = {en},
	number = {2},
	urldate = {2021-06-08},
	journal = {Journal of Experimental Botany},
	author = {Guenin, S. and Mauriat, M. and Pelloux, J. and Van Wuytswinkel, O. and Bellini, C. and Gutierrez, L.},
	month = jan,
	year = {2009},
	pages = {487--493},
}

@article{gutierrez_phenotypic_2009,
	title = {Phenotypic {Plasticity} of {Adventitious} {Rooting} in \textit{{Arabidopsis}} {Is} {Controlled} by {Complex} {Regulation} of {AUXIN} {RESPONSE} {FACTOR} {Transcripts} and {MicroRNA} {Abundance}},
	volume = {21},
	issn = {1532-298X, 1040-4651},
	url = {https://academic.oup.com/plcell/article/21/10/3119/6096289},
	doi = {10/c7kpnr},
	abstract = {Abstract
            The development of shoot-borne roots, or adventitious roots, is indispensable for mass propagation of elite genotypes. It is a complex genetic trait with a high phenotypic plasticity due to multiple endogenous and environmental regulatory factors. We demonstrate here that a subtle balance of activator and repressor AUXIN RESPONSE FACTOR (ARF) transcripts controls adventitious root initiation. Moreover, microRNA activity appears to be required for fine-tuning of this process. Thus, ARF17, a target of miR160, is a negative regulator, and ARF6 and ARF8, targets of miR167, are positive regulators of adventitious rooting. The three ARFs display overlapping expression domains, interact genetically, and regulate each other's expression at both transcriptional and posttranscriptional levels by modulating miR160 and miR167 availability. This complex regulatory network includes an unexpected feedback regulation of microRNA homeostasis by direct and nondirect target transcription factors. These results provide evidence of microRNA control of phenotypic variability and are a significant step forward in understanding the molecular mechanisms regulating adventitious rooting.},
	language = {en},
	number = {10},
	urldate = {2021-06-08},
	journal = {The Plant Cell},
	author = {Gutierrez, Laurent and Bussell, John D. and Păcurar, Daniel I. and Schwambach, Josèli and Păcurar, Monica and Bellini, Catherine},
	month = dec,
	year = {2009},
	pages = {3119--3132},
}

Abstract The development of shoot-borne roots, or adventitious roots, is indispensable for mass propagation of elite genotypes. It is a complex genetic trait with a high phenotypic plasticity due to multiple endogenous and environmental regulatory factors. We demonstrate here that a subtle balance of activator and repressor AUXIN RESPONSE FACTOR (ARF) transcripts controls adventitious root initiation. Moreover, microRNA activity appears to be required for fine-tuning of this process. Thus, ARF17, a target of miR160, is a negative regulator, and ARF6 and ARF8, targets of miR167, are positive regulators of adventitious rooting. The three ARFs display overlapping expression domains, interact genetically, and regulate each other's expression at both transcriptional and posttranscriptional levels by modulating miR160 and miR167 availability. This complex regulatory network includes an unexpected feedback regulation of microRNA homeostasis by direct and nondirect target transcription factors. These results provide evidence of microRNA control of phenotypic variability and are a significant step forward in understanding the molecular mechanisms regulating adventitious rooting.

@article{le_hir_gene_2008,
	title = {Gene expression profiling: keys for investigating phloem functions},
	volume = {13},
	issn = {13601385},
	shorttitle = {Gene expression profiling},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S1360138508001301},
	doi = {10/b4c2q3},
	language = {en},
	number = {6},
	urldate = {2021-06-10},
	journal = {Trends in Plant Science},
	author = {Le Hir, Rozenn and Beneteau, Julie and Bellini, Catherine and Vilaine, Françoise and Dinant, Sylvie},
	month = jun,
	year = {2008},
	pages = {273--280},
}

@article{gutierrez_lack_2008,
	title = {The lack of a systematic validation of reference genes: a serious pitfall undervalued in reverse transcription-polymerase chain reaction ({RT}-{PCR}) analysis in plants},
	volume = {6},
	issn = {14677644, 14677652},
	shorttitle = {The lack of a systematic validation of reference genes},
	url = {http://doi.wiley.com/10.1111/j.1467-7652.2008.00346.x},
	doi = {10/d6bcb9},
	language = {en},
	number = {6},
	urldate = {2021-06-10},
	journal = {Plant Biotechnology Journal},
	author = {Gutierrez, Laurent and Mauriat, Mlanie and Gunin, Stphanie and Pelloux, Jrme and Lefebvre, Jean-Franois and Louvet, Romain and Rusterucci, Christine and Moritz, Thomas and Guerineau, Franois and Bellini, Catherine and Van Wuytswinkel, Olivier},
	month = aug,
	year = {2008},
	pages = {609--618},
}

@article{gutierrez_towards_2008,
	title = {Towards a {Systematic} {Validation} of {References} in {Real}-{Time} {RT}-{PCR}},
	volume = {20},
	issn = {1040-4651, 1532-298X},
	url = {https://academic.oup.com/plcell/article/20/7/1734-1735/6092386},
	doi = {10/drh6vn},
	language = {en},
	number = {7},
	urldate = {2021-06-10},
	journal = {The Plant Cell},
	author = {Gutierrez, Laurent and Mauriat, Mélanie and Pelloux, Jérôme and Bellini, Catherine and Van Wuytswinkel, Olivier},
	month = jul,
	year = {2008},
	pages = {1734--1735},
}

@article{gutierrez_combined_2007,
	title = {Combined networks regulating seed maturation},
	volume = {12},
	issn = {13601385},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S1360138507001343},
	doi = {10/d2p7pf},
	language = {en},
	number = {7},
	urldate = {2021-06-10},
	journal = {Trends in Plant Science},
	author = {Gutierrez, Laurent and Van Wuytswinkel, Olivier and Castelain, Mathieu and Bellini, Catherine},
	month = jul,
	year = {2007},
	pages = {294--300},
}

@article{svennerstam_comprehensive_2007,
	title = {Comprehensive {Screening} of {Arabidopsis} {Mutants} {Suggests} the {Lysine} {Histidine} {Transporter} 1 to {Be} {Involved} in {Plant} {Uptake} of {Amino} {Acids}},
	volume = {143},
	issn = {1532-2548},
	url = {https://academic.oup.com/plphys/article/143/4/1853/6106923},
	doi = {10/cgtd2h},
	abstract = {Abstract
            Plant nitrogen (N) uptake is a key process in the global N cycle and is usually considered a “bottleneck” for biomass production in land ecosystems. Earlier, mineral N was considered the only form available to plants. Recent studies have questioned this dogma and shown that plants may access organic N sources such as amino acids. The actual mechanism enabling plants to access amino acid N is still unknown. However, a recent study suggested the Lysine Histidine Transporter 1 (LHT1) to be involved in root amino acid uptake. In this study, we isolated mutants defective in root amino acid uptake by screening Arabidopsis (Arabidopsis thaliana) seeds from ethyl methanesulfonate-treated plants and seeds from amino acid transporter T-DNA knockout mutants for resistance against the toxic d-enantiomer of alanine (Ala). Both ethyl methanesulfonate and T-DNA knockout plants identified as d-Ala resistant were found to be mutated in the LHT1 gene. LHT1 mutants displayed impaired capacity for uptake of a range of amino acids from solutions, displayed impaired growth when N was supplied in organic forms, and acquired substantially lower amounts of amino acids than wild-type plants from solid growth media. LHT1 mutants grown on mineral N did not display a phenotype until at the stage of flowering, when premature senescence of old leaf pairs occurred, suggesting that LHT1 may fulfill an important function at this developmental stage. Based on the broad and unbiased screening of mutants resistant to d-Ala, we suggest that LHT1 is an important mediator of root uptake of amino acids. This provides a molecular background for plant acquisition of organic N from the soil.},
	language = {en},
	number = {4},
	urldate = {2021-06-10},
	journal = {Plant Physiology},
	author = {Svennerstam, Henrik and Ganeteg, Ulrika and Bellini, Catherine and Näsholm, Torgny},
	month = apr,
	year = {2007},
	pages = {1853--1860},
}

Abstract Plant nitrogen (N) uptake is a key process in the global N cycle and is usually considered a “bottleneck” for biomass production in land ecosystems. Earlier, mineral N was considered the only form available to plants. Recent studies have questioned this dogma and shown that plants may access organic N sources such as amino acids. The actual mechanism enabling plants to access amino acid N is still unknown. However, a recent study suggested the Lysine Histidine Transporter 1 (LHT1) to be involved in root amino acid uptake. In this study, we isolated mutants defective in root amino acid uptake by screening Arabidopsis (Arabidopsis thaliana) seeds from ethyl methanesulfonate-treated plants and seeds from amino acid transporter T-DNA knockout mutants for resistance against the toxic d-enantiomer of alanine (Ala). Both ethyl methanesulfonate and T-DNA knockout plants identified as d-Ala resistant were found to be mutated in the LHT1 gene. LHT1 mutants displayed impaired capacity for uptake of a range of amino acids from solutions, displayed impaired growth when N was supplied in organic forms, and acquired substantially lower amounts of amino acids than wild-type plants from solid growth media. LHT1 mutants grown on mineral N did not display a phenotype until at the stage of flowering, when premature senescence of old leaf pairs occurred, suggesting that LHT1 may fulfill an important function at this developmental stage. Based on the broad and unbiased screening of mutants resistant to d-Ala, we suggest that LHT1 is an important mediator of root uptake of amino acids. This provides a molecular background for plant acquisition of organic N from the soil.

@article{sorin_proteomic_2006,
	title = {Proteomic analysis of different mutant genotypes of {Arabidopsis} led to the identification of 11 proteins correlating with adventitious root development},
	volume = {140},
	issn = {0032-0889},
	doi = {10/bqsw6z},
	abstract = {A lack of competence to form adventitious roots by cuttings or explants in vitro occurs routinely and is an obstacle for the clonal propagation and rapid fixation of elite genotypes. Adventitious rooting is known to be a quantitative genetic trait. We performed a proteomic analysis of Arabidopsis ( Arabidopsis thaliana) mutants affected in their ability to develop adventitious roots in order to identify associated molecular markers that could be used to select genotypes for their rooting ability and/or to get further insight into the molecular mechanisms controlling adventitious rooting. Comparison of two-dimensional gel electrophoresis protein profiles resulted in the identification of 11 proteins whose abundance could be either positively or negatively correlated with endogenous auxin content, the number of adventitious root primordia, and/or the number of mature adventitious roots. One protein was negatively correlated only to the number of root primordia and two were negatively correlated to the number of mature adventitious roots. Two putative chaperone proteins were positively correlated only to the number of primordia, and, interestingly, three auxin-inducible GH3-like proteins were positively correlated with the number of mature adventitious roots. The others were correlated with more than one parameter. The 11 proteins are predicted to be involved in different biological processes, including the regulation of auxin homeostasis and light-associated metabolic pathways. The results identify regulatory pathways associated with adventitious root formation and represent valuable markers that might be used for the future identification of genotypes with better rooting abilities.},
	language = {English},
	number = {1},
	journal = {Plant Physiology},
	author = {Sorin, C. and Negroni, L. and Balliau, T. and Corti, H. and Jacquemot, M. P. and Davanture, M. and Sandberg, G. and Zivy, M. and Bellini, C.},
	month = jan,
	year = {2006},
	note = {Place: Rockville
Publisher: Amer Soc Plant Biologists
WOS:000234492100031},
	keywords = {ago1, auxin, cuttings, cyp83b1, cytochrome-p450, expression, genetic-analysis, glucosinolate biosynthesis, light, locus},
	pages = {349--364},
}

A lack of competence to form adventitious roots by cuttings or explants in vitro occurs routinely and is an obstacle for the clonal propagation and rapid fixation of elite genotypes. Adventitious rooting is known to be a quantitative genetic trait. We performed a proteomic analysis of Arabidopsis ( Arabidopsis thaliana) mutants affected in their ability to develop adventitious roots in order to identify associated molecular markers that could be used to select genotypes for their rooting ability and/or to get further insight into the molecular mechanisms controlling adventitious rooting. Comparison of two-dimensional gel electrophoresis protein profiles resulted in the identification of 11 proteins whose abundance could be either positively or negatively correlated with endogenous auxin content, the number of adventitious root primordia, and/or the number of mature adventitious roots. One protein was negatively correlated only to the number of root primordia and two were negatively correlated to the number of mature adventitious roots. Two putative chaperone proteins were positively correlated only to the number of primordia, and, interestingly, three auxin-inducible GH3-like proteins were positively correlated with the number of mature adventitious roots. The others were correlated with more than one parameter. The 11 proteins are predicted to be involved in different biological processes, including the regulation of auxin homeostasis and light-associated metabolic pathways. The results identify regulatory pathways associated with adventitious root formation and represent valuable markers that might be used for the future identification of genotypes with better rooting abilities.

@article{sorin_auxin_2005,
	title = {Auxin and {Light} {Control} of {Adventitious} {Rooting} in {Arabidopsis} {Require} {ARGONAUTE1}},
	volume = {17},
	issn = {1040-4651},
	url = {https://doi.org/10.1105/tpc.105.031625},
	doi = {10/bsmnt5},
	abstract = {Adventitious rooting is a quantitative genetic trait regulated by both environmental and endogenous factors. To better understand the physiological and molecular basis of adventitious rooting, we took advantage of two classes of Arabidopsis thaliana mutants altered in adventitious root formation: the superroot mutants, which spontaneously make adventitious roots, and the argonaute1 (ago1) mutants, which unlike superroot are barely able to form adventitious roots. The defect in adventitious rooting observed in ago1 correlated with light hypersensitivity and the deregulation of auxin homeostasis specifically in the apical part of the seedlings. In particular, a clear reduction in endogenous levels of free indoleacetic acid (IAA) and IAA conjugates was shown. This was correlated with a downregulation of the expression of several auxin-inducible GH3 genes in the hypocotyl of the ago1-3 mutant. We also found that the Auxin Response Factor17 (ARF17) gene, a potential repressor of auxin-inducible genes, was overexpressed in ago1-3 hypocotyls. The characterization of an ARF17-overexpressing line showed that it produced fewer adventitious roots than the wild type and retained a lower expression of GH3 genes. Thus, we suggest that ARF17 negatively regulates adventitious root formation in ago1 mutants by repressing GH3 genes and therefore perturbing auxin homeostasis in a light-dependent manner. These results suggest that ARF17 could be a major regulator of adventitious rooting in Arabidopsis.},
	number = {5},
	urldate = {2021-06-11},
	journal = {The Plant Cell},
	author = {Sorin, Céline and Bussell, John D. and Camus, Isabelle and Ljung, Karin and Kowalczyk, Mariusz and Geiss, Gaia and McKhann, Heather and Garcion, Christophe and Vaucheret, Hervé and Sandberg, Göran and Bellini, Catherine},
	month = may,
	year = {2005},
	pages = {1343--1359},
}

Adventitious rooting is a quantitative genetic trait regulated by both environmental and endogenous factors. To better understand the physiological and molecular basis of adventitious rooting, we took advantage of two classes of Arabidopsis thaliana mutants altered in adventitious root formation: the superroot mutants, which spontaneously make adventitious roots, and the argonaute1 (ago1) mutants, which unlike superroot are barely able to form adventitious roots. The defect in adventitious rooting observed in ago1 correlated with light hypersensitivity and the deregulation of auxin homeostasis specifically in the apical part of the seedlings. In particular, a clear reduction in endogenous levels of free indoleacetic acid (IAA) and IAA conjugates was shown. This was correlated with a downregulation of the expression of several auxin-inducible GH3 genes in the hypocotyl of the ago1-3 mutant. We also found that the Auxin Response Factor17 (ARF17) gene, a potential repressor of auxin-inducible genes, was overexpressed in ago1-3 hypocotyls. The characterization of an ARF17-overexpressing line showed that it produced fewer adventitious roots than the wild type and retained a lower expression of GH3 genes. Thus, we suggest that ARF17 negatively regulates adventitious root formation in ago1 mutants by repressing GH3 genes and therefore perturbing auxin homeostasis in a light-dependent manner. These results suggest that ARF17 could be a major regulator of adventitious rooting in Arabidopsis.

@article{bennett_integrative_2005,
	title = {Integrative biology: dissecting cross-talk between plant signalling pathways},
	volume = {123},
	issn = {0031-9317},
	shorttitle = {Integrative biology},
	doi = {10/bwb463},
	language = {English},
	number = {2},
	journal = {Physiologia Plantarum},
	author = {Bennett, M. and Bellini, C. and Van Der Straeten, D.},
	month = feb,
	year = {2005},
	note = {Place: Hoboken
Publisher: Wiley
WOS:000226966400001},
	keywords = {ethylene, gene, growth},
	pages = {109--110},
}

@article{baud_gurke_2004,
	title = {gurke and pasticcino3 mutants affected in embryo development are impaired in acetyl-{CoA} carboxylase},
	volume = {5},
	issn = {1469-221X},
	url = {https://www.embopress.org/doi/full/10.1038/sj.embor.7400124},
	doi = {10.1038/sj.embor.7400124},
	abstract = {Normal embryo development is required for correct seedling formation. The Arabidopsis gurke and pasticcino3 mutants were isolated from different developmental screens and the corresponding embryos exhibit severe defects in their apical region, affecting bilateral symmetry. We have recently identified lethal acc1 mutants affected in acetyl-CoA carboxylase 1 (ACCase 1) that display a similar embryo phenotype. A series of crosses showed that gk and pas3 are allelic to acc1 mutants, and direct sequencing of the ACC1 gene revealed point mutations in these new alleles. The isolation of leaky acc1 alleles demonstrated that ACCase 1 is essential for correct plant development and that mutations in ACCase affect cellular division in plants, as is the case in yeast. Interestingly, significant metabolic complementation of the mutant phenotype was obtained by exogenous supply of malonate, suggesting that the lack of cytosolic malonyl-CoA is likely to be the initial factor leading to abnormal development in the acc1 mutants.},
	number = {5},
	urldate = {2021-06-30},
	journal = {EMBO reports},
	author = {Baud, Sébastien and Bellec, Yannick and Miquel, Martine and Bellini, Catherine and Caboche, Michel and Lepiniec, Loïc and Faure, Jean-Denis and Rochat, Christine},
	month = may,
	year = {2004},
	note = {Publisher: John Wiley \& Sons, Ltd},
	keywords = {cell division, embryo development, plant development, very-long-chain fatty acids},
	pages = {515--520},
}

Normal embryo development is required for correct seedling formation. The Arabidopsis gurke and pasticcino3 mutants were isolated from different developmental screens and the corresponding embryos exhibit severe defects in their apical region, affecting bilateral symmetry. We have recently identified lethal acc1 mutants affected in acetyl-CoA carboxylase 1 (ACCase 1) that display a similar embryo phenotype. A series of crosses showed that gk and pas3 are allelic to acc1 mutants, and direct sequencing of the ACC1 gene revealed point mutations in these new alleles. The isolation of leaky acc1 alleles demonstrated that ACCase 1 is essential for correct plant development and that mutations in ACCase affect cellular division in plants, as is the case in yeast. Interestingly, significant metabolic complementation of the mutant phenotype was obtained by exogenous supply of malonate, suggesting that the lack of cytosolic malonyl-CoA is likely to be the initial factor leading to abnormal development in the acc1 mutants.

@article{schrick_interactions_2002,
	title = {Interactions between sterol biosynthesis genes in embryonic development of {Arabidopsis}},
	volume = {31},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313X.2002.01333.x},
	doi = {10/fv724z},
	abstract = {The sterol biosynthesis pathway of Arabidopsis produces a large set of structurally related phytosterols including sitosterol and campesterol, the latter being the precursor of the brassinosteroids (BRs). While BRs are implicated as phytohormones in post-embryonic growth, the functions of other types of steroid molecules are not clear. Characterization of the fackel (fk) mutants provided the first hint that sterols play a role in plant embryogenesis. FK encodes a sterol C-14 reductase that acts upstream of all known enzymatic steps corresponding to BR biosynthesis mutants. Here we report that genetic screens for fk-like seedling and embryonic phenotypes have identified two additional genes coding for sterol biosynthesis enzymes: CEPHALOPOD (CPH), a C-24 sterol methyl transferase, and HYDRA1 (HYD1), a sterol C-8,7 isomerase. We describe genetic interactions between cph, hyd1 and fk, and studies with 15-azasterol, an inhibitor of sterol C-14 reductase. Our experiments reveal that FK and HYD1 act sequentially, whereas CPH acts independently of these genes to produce essential sterols. Similar experiments indicate that the BR biosynthesis gene DWF1 acts independently of FK, whereas BR receptor gene BRI1 acts downstream of FK to promote post-embryonic growth. We found embryonic patterning defects in cph mutants and describe a GC–MS analysis of cph tissues which suggests that steroid molecules in addition to BRs play critical roles during plant embryogenesis. Taken together, our results imply that the sterol biosynthesis pathway is not a simple linear pathway but a complex network of enzymes that produce essential steroid molecules for plant growth and development.},
	language = {en},
	number = {1},
	urldate = {2021-10-19},
	journal = {The Plant Journal},
	author = {Schrick, Kathrin and Mayer, Ulrike and Martin, Gottfried and Bellini, Catherine and Kuhnt, Christine and Schmidt, Jürgen and Jürgens, Gerd},
	year = {2002},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313X.2002.01333.x},
	keywords = {15-azasterol, Arabidopsis, GC–MS, brassinosteroids., embryogenesis, sterols},
	pages = {61--73},
}

The sterol biosynthesis pathway of Arabidopsis produces a large set of structurally related phytosterols including sitosterol and campesterol, the latter being the precursor of the brassinosteroids (BRs). While BRs are implicated as phytohormones in post-embryonic growth, the functions of other types of steroid molecules are not clear. Characterization of the fackel (fk) mutants provided the first hint that sterols play a role in plant embryogenesis. FK encodes a sterol C-14 reductase that acts upstream of all known enzymatic steps corresponding to BR biosynthesis mutants. Here we report that genetic screens for fk-like seedling and embryonic phenotypes have identified two additional genes coding for sterol biosynthesis enzymes: CEPHALOPOD (CPH), a C-24 sterol methyl transferase, and HYDRA1 (HYD1), a sterol C-8,7 isomerase. We describe genetic interactions between cph, hyd1 and fk, and studies with 15-azasterol, an inhibitor of sterol C-14 reductase. Our experiments reveal that FK and HYD1 act sequentially, whereas CPH acts independently of these genes to produce essential sterols. Similar experiments indicate that the BR biosynthesis gene DWF1 acts independently of FK, whereas BR receptor gene BRI1 acts downstream of FK to promote post-embryonic growth. We found embryonic patterning defects in cph mutants and describe a GC–MS analysis of cph tissues which suggests that steroid molecules in addition to BRs play critical roles during plant embryogenesis. Taken together, our results imply that the sterol biosynthesis pathway is not a simple linear pathway but a complex network of enzymes that produce essential steroid molecules for plant growth and development.

@article{bellec_pasticcino2_2002,
	title = {Pasticcino2 is a protein tyrosine phosphatase-like involved in cell proliferation and differentiation in {Arabidopsis}},
	volume = {32},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313X.2002.01456.x},
	doi = {10/cgckd9},
	abstract = {The pasticcino2 (pas2) mutant shows impaired embryo and seedling development associated with cell de-differentiation and proliferation. This process is specifically enhanced in presence of cytokinins leading to callus-like structure of the apical part of the seedling. Cell proliferation concerns localized and stochastic nodules of dividing cells. In absence of cytokinins, cell proliferation leads to small calli on stems but, most often, cell proliferation is associated with post-genital organ fusion. The PAS2 gene was identified by positional cloning. PAS2 expression was found in every plant organ and was not regulated by PAS1 and PAS3 genes. PAS2 encodes the Arabidopsis member of the protein tyrosine phosphatase-like (Ptpl) family, a new PTP family originally described in mice and humans and characterized by a mutated PTP active site. This family of proteins has a yeast homolog that is essential for cell viability. The absence of yeast PAS2 homolog can be functionally replaced by the Arabidopsis PAS2 protein, demonstrating that PAS2 function is conserved between higher and lower eukaryotes.},
	language = {en},
	number = {5},
	urldate = {2021-10-19},
	journal = {The Plant Journal},
	author = {Bellec, Yannick and Harrar, Yaël and Butaeye, Christelle and Darnet, Sylvain and Bellini, Catherine and Faure, Jean-Denis},
	year = {2002},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313X.2002.01456.x},
	keywords = {Ptpl, YJL097w, cytokinins, protein tyrosine phosphatase, tumor},
	pages = {713--722},
}

The pasticcino2 (pas2) mutant shows impaired embryo and seedling development associated with cell de-differentiation and proliferation. This process is specifically enhanced in presence of cytokinins leading to callus-like structure of the apical part of the seedling. Cell proliferation concerns localized and stochastic nodules of dividing cells. In absence of cytokinins, cell proliferation leads to small calli on stems but, most often, cell proliferation is associated with post-genital organ fusion. The PAS2 gene was identified by positional cloning. PAS2 expression was found in every plant organ and was not regulated by PAS1 and PAS3 genes. PAS2 encodes the Arabidopsis member of the protein tyrosine phosphatase-like (Ptpl) family, a new PTP family originally described in mice and humans and characterized by a mutated PTP active site. This family of proteins has a yeast homolog that is essential for cell viability. The absence of yeast PAS2 homolog can be functionally replaced by the Arabidopsis PAS2 protein, demonstrating that PAS2 function is conserved between higher and lower eukaryotes.

@article{camilleri_arabidopsis_2002,
	title = {The {Arabidopsis} {TONNEAU2} {Gene} {Encodes} a {Putative} {Novel} {Protein} {Phosphatase} {2A} {Regulatory} {Subunit} {Essential} for the {Control} of the {Cortical} {Cytoskeleton}},
	volume = {14},
	issn = {1040-4651},
	url = {https://doi.org/10.1105/tpc.010402},
	doi = {10/d79s3z},
	abstract = {In Arabidopsis ton2 mutants, abnormalities of the cortical microtubular cytoskeleton, such as disorganization of the interphase microtubule array and lack of the preprophase band before mitosis, markedly affect cell shape and arrangement as well as overall plant morphology. We present the molecular isolation of the TON2 gene, which is highly conserved in higher plants and has a vertebrate homolog of unknown function. It encodes a protein similar in its C-terminal part to B″ regulatory subunits of type 2A protein phosphatases (PP2As). We show that the TON2 protein interacts with an Arabidopsis type A subunit of PP2A in the yeast two-hybrid system and thus likely defines a novel subclass of PP2A subunits that are possibly involved in the control of cytoskeletal structures in plants.},
	number = {4},
	urldate = {2021-10-19},
	journal = {The Plant Cell},
	author = {Camilleri, Christine and Azimzadeh, Juliette and Pastuglia, Martine and Bellini, Catherine and Grandjean, Olivier and Bouchez, David},
	month = apr,
	year = {2002},
	pages = {833--845},
}

In Arabidopsis ton2 mutants, abnormalities of the cortical microtubular cytoskeleton, such as disorganization of the interphase microtubule array and lack of the preprophase band before mitosis, markedly affect cell shape and arrangement as well as overall plant morphology. We present the molecular isolation of the TON2 gene, which is highly conserved in higher plants and has a vertebrate homolog of unknown function. It encodes a protein similar in its C-terminal part to B″ regulatory subunits of type 2A protein phosphatases (PP2As). We show that the TON2 protein interacts with an Arabidopsis type A subunit of PP2A in the yeast two-hybrid system and thus likely defines a novel subclass of PP2A subunits that are possibly involved in the control of cytoskeletal structures in plants.

@article{harrar_fkbps_2001,
	title = {{FKBPs}: at the crossroads of folding and transduction},
	volume = {6},
	issn = {1360-1385},
	shorttitle = {{FKBPs}},
	url = {https://www.sciencedirect.com/science/article/pii/S1360138501020441},
	doi = {10/c79bct},
	abstract = {FK506-binding proteins (FKBPs) belong to the large family of peptidyl–prolyl cis–trans isomerases, which are known to be involved in many cellular processes, such as cell signalling, protein trafficking and transcription. FKBPs associate into protein complexes, although the involvement and precise role of their foldase activity remain to be elucidated. FKBPs represent a large gene family in plants that is involved in growth and development. Disruption of genes encoding FKBPs in plants and animals has underlined the importance of this family of proteins in the regulation of cell division and differentiation.},
	language = {en},
	number = {9},
	urldate = {2021-11-02},
	journal = {Trends in Plant Science},
	author = {Harrar, Yaël and Bellini, Catherine and Faure, Jean-Denis},
	month = sep,
	year = {2001},
	keywords = {Heat shock protein, Ppiase, calcineurin, calcium channel, cell division and differentiation, immunophilin, pasticcino1, receptors, rotamase, salt stress, steroid and TGFβ},
	pages = {426--431},
}

FK506-binding proteins (FKBPs) belong to the large family of peptidyl–prolyl cis–trans isomerases, which are known to be involved in many cellular processes, such as cell signalling, protein trafficking and transcription. FKBPs associate into protein complexes, although the involvement and precise role of their foldase activity remain to be elucidated. FKBPs represent a large gene family in plants that is involved in growth and development. Disruption of genes encoding FKBPs in plants and animals has underlined the importance of this family of proteins in the regulation of cell division and differentiation.

@article{carol_pasticcino1_2001,
	title = {{PASTICCINO1} ({AtFKBP70}) is a nuclear-localised immunophilin required during {Arabidopsis} thaliana embryogenesis},
	volume = {161},
	issn = {0168-9452},
	url = {https://www.sciencedirect.com/science/article/pii/S016894520100437X},
	doi = {10/bwth5k},
	abstract = {The PASTICCINO1 (PAS1) gene of Arabidopsis thaliana encodes a protein with homology to the FK506-binding protein (FKBP) class of immunophilins. To begin to understand more about the possible function of PAS1, we tested some properties of recombinant PAS1 protein and analysed the expression of the gene in Arabidopsis embryos and cell cultures and in tobacco cells. In pas1-1/+ heterozygote embryos the pas1-1 allele is expressed at very low levels in all cells, but it is misexpressed in the pas1-1 homozygote mutant at the same stage. Anti-PAS1 affinity-purified antibodies recognise a 70 kDa protein from dividing cell cultures of Arabidopsis. In indirect immunofluorescence, the same antibodies label the nuclei of dividing tobacco BY-2 cells. In a protease-coupled assay, recombinant PAS1 protein has low peptidylprolyl cis–trans isomerase (PPIase) activity, which is inhibited by the immunosuppressive drugs FK506 and rapamycin, but not by cyclosporin. PAS1 also binds calmodulin in vitro. This data suggests the importance of the correctly regulated production of functional PAS1 protein, a likely nuclear-localised FKBP, for the correct development of the plant embryo.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Plant Science},
	author = {Carol, Rachel J. and Breiman, Adina and Erel, Noa and Vittorioso, Paola and Bellini, Catherine},
	month = aug,
	year = {2001},
	keywords = {Calmodulin, Embryogenesis, FKBP, Nucleus, PPIase},
	pages = {527--535},
}

The PASTICCINO1 (PAS1) gene of Arabidopsis thaliana encodes a protein with homology to the FK506-binding protein (FKBP) class of immunophilins. To begin to understand more about the possible function of PAS1, we tested some properties of recombinant PAS1 protein and analysed the expression of the gene in Arabidopsis embryos and cell cultures and in tobacco cells. In pas1-1/+ heterozygote embryos the pas1-1 allele is expressed at very low levels in all cells, but it is misexpressed in the pas1-1 homozygote mutant at the same stage. Anti-PAS1 affinity-purified antibodies recognise a 70 kDa protein from dividing cell cultures of Arabidopsis. In indirect immunofluorescence, the same antibodies label the nuclei of dividing tobacco BY-2 cells. In a protease-coupled assay, recombinant PAS1 protein has low peptidylprolyl cis–trans isomerase (PPIase) activity, which is inhibited by the immunosuppressive drugs FK506 and rapamycin, but not by cyclosporin. PAS1 also binds calmodulin in vitro. This data suggests the importance of the correctly regulated production of functional PAS1 protein, a likely nuclear-localised FKBP, for the correct development of the plant embryo.

@article{fagard_ago1_2000,
	title = {{AGO1}, {QDE}-2, and {RDE}-1 are related proteins required for post-transcriptional gene silencing in plants, quelling in fungi, and {RNA} interference in animals},
	volume = {97},
	copyright = {Copyright © 2000, The National Academy of Sciences},
	issn = {0027-8424, 1091-6490},
	url = {https://www.pnas.org/content/97/21/11650},
	doi = {10/dbx439},
	abstract = {Introduction of transgene DNA may lead to specific degradation of RNAs that are homologous to the transgene transcribed sequence through phenomena named post-transcriptional gene silencing (PTGS) in plants, quelling in fungi, and RNA interference (RNAi) in animals. It was shown previously that PTGS, quelling, and RNAi require a set of related proteins (SGS2, QDE-1, and EGO-1, respectively). Here we report the isolation of Arabidopsis mutants impaired in PTGS which are affected at the Argonaute1 (AGO1) locus. AGO1 is similar to QDE-2 required for quelling and RDE-1 required for RNAi. Sequencing of ago1 mutants revealed one amino acid essential for PTGS that is also present in QDE-2 and RDE-1 in a highly conserved motif. Taken together, these results confirm the hypothesis that these processes derive from a common ancestral mechanism that controls expression of invading nucleic acid molecules at the post-transcriptional level. As opposed to rde-1 and qde-2 mutants, which are viable, ago1 mutants display several developmental abnormalities, including sterility. These results raise the possibility that PTGS, or at least some of its elements, could participate in the regulation of gene expression during development in plants.},
	language = {en},
	number = {21},
	urldate = {2021-11-08},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Fagard, Mathilde and Boutet, Stéphanie and Morel, Jean-Benoit and Bellini, Catherine and Vaucheret, Hervé},
	month = oct,
	year = {2000},
	pmid = {11016954},
	note = {Publisher: National Academy of Sciences
Section: Biological Sciences},
	pages = {11650--11654},
}

Introduction of transgene DNA may lead to specific degradation of RNAs that are homologous to the transgene transcribed sequence through phenomena named post-transcriptional gene silencing (PTGS) in plants, quelling in fungi, and RNA interference (RNAi) in animals. It was shown previously that PTGS, quelling, and RNAi require a set of related proteins (SGS2, QDE-1, and EGO-1, respectively). Here we report the isolation of Arabidopsis mutants impaired in PTGS which are affected at the Argonaute1 (AGO1) locus. AGO1 is similar to QDE-2 required for quelling and RDE-1 required for RNAi. Sequencing of ago1 mutants revealed one amino acid essential for PTGS that is also present in QDE-2 and RDE-1 in a highly conserved motif. Taken together, these results confirm the hypothesis that these processes derive from a common ancestral mechanism that controls expression of invading nucleic acid molecules at the post-transcriptional level. As opposed to rde-1 and qde-2 mutants, which are viable, ago1 mutants display several developmental abnormalities, including sterility. These results raise the possibility that PTGS, or at least some of its elements, could participate in the regulation of gene expression during development in plants.

@article{schrick_fackel_2000,
	title = {{FACKEL} is a sterol {C}-14 reductase required for organized cell division and expansion in {Arabidopsis} embryogenesis},
	volume = {14},
	url = {https://www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC316688/},
	abstract = {In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. ...},
	language = {en},
	number = {12},
	urldate = {2021-11-08},
	journal = {Genes \& Development},
	author = {Schrick, Kathrin and Mayer, Ulrike and Horrichs, Andrea and Kuhnt, Christine and Bellini, Catherine and Dangl, Jeff and Schmidt, Jürgen and Jürgens, Gerd},
	month = jun,
	year = {2000},
	pmid = {10859166},
	note = {Publisher: Cold Spring Harbor Laboratory Press},
	pages = {1471},
}

In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. ...

@article{barlier_sur2_2000,
	title = {The {SUR2} gene of {Arabidopsis} thaliana encodes the cytochrome {P450} {CYP83B1}, a modulator of auxin homeostasis},
	volume = {97},
	copyright = {Copyright © 2000, The National Academy of Sciences},
	issn = {0027-8424, 1091-6490},
	url = {https://www.pnas.org/content/97/26/14819},
	doi = {10/c36wb6},
	abstract = {Genetic screens have been performed to identify mutants with altered auxin homeostasis in Arabidopsis. A tagged allele of the auxin-overproducing mutant sur2 was identified within a transposon mutagenized population. The SUR2 gene was cloned and shown to encode the CYP83B1 protein, which belongs to the large family of the P450-dependent monooxygenases. SUR2 expression is up-regulated in sur1 mutants and induced by exogenous auxin in the wild type. Analysis of indole-3-acetic acid (IAA) synthesis and metabolism in sur2 plants indicates that the mutation causes a conditional increase in the pool size of IAA through up-regulation of IAA synthesis.},
	language = {en},
	number = {26},
	urldate = {2021-11-08},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Barlier, Isabelle and Kowalczyk, Mariusz and Marchant, Alan and Ljung, Karin and Bhalerao, Rishikesh and Bennett, Malcolm and Sandberg, Goeran and Bellini, Catherine},
	month = dec,
	year = {2000},
	pmid = {11114200},
	note = {Publisher: National Academy of Sciences
Section: Biological Sciences},
	keywords = {metabolism},
	pages = {14819--14824},
}

Genetic screens have been performed to identify mutants with altered auxin homeostasis in Arabidopsis. A tagged allele of the auxin-overproducing mutant sur2 was identified within a transposon mutagenized population. The SUR2 gene was cloned and shown to encode the CYP83B1 protein, which belongs to the large family of the P450-dependent monooxygenases. SUR2 expression is up-regulated in sur1 mutants and induced by exogenous auxin in the wild type. Analysis of indole-3-acetic acid (IAA) synthesis and metabolism in sur2 plants indicates that the mutation causes a conditional increase in the pool size of IAA through up-regulation of IAA synthesis.

@article{delarue_increased_1999,
	title = {Increased auxin efflux in the {IAA}-overproducing sur1 mutant of {Arabidopsis} thaliana: {A} mechanism of reducing auxin levels?},
	volume = {107},
	issn = {1399-3054},
	shorttitle = {Increased auxin efflux in the {IAA}-overproducing sur1 mutant of {Arabidopsis} thaliana},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.1999.100116.x},
	doi = {10.1034/j.1399-3054.1999.100116.x},
	abstract = {With the aim of investigating the mechanisms that maintain auxin homeostasis in plants, we have monitored the net uptake and metabolism of exogenously supplied indole-3-acetic acid (IAA) and naphthalene-1-acetic acid (NAA) in seedlings of wild type and the IAA-overproducing mutant sur1 of Arabidopsis thaliana. Tritiated IAA and NAA entered the seedling tissues within minutes and were mostly accumulated as metabolites, probably amino acid and sugar conjugates. The mutant seedlings were marked by a strong increase of [3H]IAA metabolism and a reduction of the accumulation levels of both free [3H]IAA and [3H]NAA. The same characteristics were observed in wild-type seedlings grown on 5 μM picloram. We measured [3H]NAA uptake in the presence of high concentrations of unlabeled NAA or the auxin efflux carrier inhibitor naphthylphthalamic acid (NPA). This abolished the difference in free [3H]NAA accumulation between the mutant or picloram-treated seedlings and wild-type seedlings. These data indicated that active auxin efflux carriers were present in Arabidopsis seedling tissues. Picloram-treated seedlings and seedlings of the IAA-overproducing mutant sur1 displayed increased auxin efflux carrier activity as well as elevated conjugation of IAA. There is previous evidence to suggest that conjugation is a means to remove excess IAA in plant cells. Here, we discuss the possibility of efflux constituting an additional mechanism for regulating free IAA levels in the face of an excess auxin supply.},
	language = {en},
	number = {1},
	urldate = {2021-11-08},
	journal = {Physiologia Plantarum},
	author = {Delarue, Marianne and Muller, Philimppe and Bellini, Catherine and Delbarre, Alain},
	year = {1999},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.1999.100116.x},
	pages = {120--127},
}

With the aim of investigating the mechanisms that maintain auxin homeostasis in plants, we have monitored the net uptake and metabolism of exogenously supplied indole-3-acetic acid (IAA) and naphthalene-1-acetic acid (NAA) in seedlings of wild type and the IAA-overproducing mutant sur1 of Arabidopsis thaliana. Tritiated IAA and NAA entered the seedling tissues within minutes and were mostly accumulated as metabolites, probably amino acid and sugar conjugates. The mutant seedlings were marked by a strong increase of [3H]IAA metabolism and a reduction of the accumulation levels of both free [3H]IAA and [3H]NAA. The same characteristics were observed in wild-type seedlings grown on 5 μM picloram. We measured [3H]NAA uptake in the presence of high concentrations of unlabeled NAA or the auxin efflux carrier inhibitor naphthylphthalamic acid (NPA). This abolished the difference in free [3H]NAA accumulation between the mutant or picloram-treated seedlings and wild-type seedlings. These data indicated that active auxin efflux carriers were present in Arabidopsis seedling tissues. Picloram-treated seedlings and seedlings of the IAA-overproducing mutant sur1 displayed increased auxin efflux carrier activity as well as elevated conjugation of IAA. There is previous evidence to suggest that conjugation is a means to remove excess IAA in plant cells. Here, we discuss the possibility of efflux constituting an additional mechanism for regulating free IAA levels in the face of an excess auxin supply.