{tab=Research}

Somatic embryogenesis (SE) in conifers: a powerful research tool and a method to capture genetic gains from the breeding programs

Ulrika Egertsdotter in a growth room with plants propagated by somatic embryogenesis

Somatic embryogenesis (SE) is an in vitro based clonal propagation method that can be used as a model system for research, or for multiplication of valuable seeds of commercial value or for conservation of threatened species.

In order to meet the demands on future forests for higher productivity and also for higher adaptability to climate change, it is necessary to capture the genetic gains from the breeding programs. This can only be done by large-scale clonal propagation of elite trees selected from the breeding programs.

For spruce and other conifers, somatic embryogenesis (SE) is the only method that has the potential for clonal propagation to sufficiently large numbers of elite trees for commercial planting.

The process steps of somatic embryogenesis (SE) in conifers: it starts with the selection of elite seeds, followed by SE initiation, multiplication and maturation phases; mature embryos are selected for germination and the germinants are developing further into SE plants that on the long-term perspective produce new seedsThe process steps of somatic embryogenesis (SE) in conifers

Cost effective SE-plant production requires automated methods. Such methods have been demonstrated on a pilot scale for Swedish forestry operations.

In the UPSC SE lab, we have an automated instrument based on the same key technology utilized in the pilot system for SE plant production (the SE Fluidics System). The instrument is a valuable tool in fundamental research projects to study embryo development. It can perform dispersion, separation/singulation, image analysis and selection of plant propagules such as somatic embryos.

A collage of several photos illustrating the R&D SE Fluidics System and the different steps to singulate and harvest mature somatic embryos The R&D SE Fluidics System is mainly used for singulation and harvest of mature somatic embryos (system overview in A). Mature somatic embryos are produced in liquid medium in a temporary immersion bioreactor system (B) where hundreds to thousands of mature embryos are produced in each bioreactor (C: top view into bioreactor), or on solid medium in a petri plate (E). After processing in the Fluidics system, singulated mature embryos are analyzed by image analysis (D) and selected based on the pre-programmed selection criteria for embryos with good chances to form a plant (F).

Our research interest is to understand and explain the different processes that regulate development of conifer embryos into early-stage plants. We utilize somatic embryogenesis as a model system to study how metabolic processes are required and regulated during embryo development. By studying the nutritional requirements of the embryo during development and the correlated active cellular processes, we have found that nitrogen utilization appears to be regulated over the course of embryo development with the earlier embryo stages benefiting from a supply of organic nitrogen such as glutamine (Dahrendorf et al. 2018). During later stages of embryo development, our results indicate the importance of desiccation tolerance and suggest key functions for different types of carbohydrates (Businge et al. 2013). Key metabolic events during shoot and root apical meristem formation are associated with morphological events during early plant formation (Dobrowolska et al. 2016)

Key publications

  • Dahrendorf, J., Clapham, D., Egertsdotter, U. 2018. Analysis of Nitrogen Utilization Capability during the Proliferation and Maturation Phases of Norway Spruce (Picea abies (L.) H.Karst.) Somatic Embryogenesis. Forests 9(6): 288. https://doi.org/10.3390/f9060288
  • Dobrowolska, I., Businge, E., Abreu, I.N., Moritz, T., Egertsdotter, U. 2017. Metabolome and transcriptome profiling reveal new insights into somatic embryo germination in Norway spruce (Picea abies). Tree Physiology 00, 1–15. https://doi.org/10.1093/treephys/tpx078
  • Businge E, Bygdell J, Wingsle G, Moritz T, Egertsdotter U. (2013). The effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce somatic embryos. Physiologia plantarum 149(2): 273–285. https://doi.org/10.1111/ppl.12039
{tab=Team}
  • Personnel Image
    Dobrenel, Thomas
    Research Engineer
    E-mail
    Room: B4-36-45
  • Personnel Image
    Egertsdotter, Ulrika
    Professor
    E-mail
    Room: B6-44-45
    Website
  • Personnel Image
    Johansson, Sofie
    Research Engineer
    E-mail
    Room: B6-38-45
  • Personnel Image
    Rizvi, Ahsan
    PostDoc
    E-mail
    Room: B3-48-51

{tab=CV U. Egertsdotter}

Professional Preparation

  • 1996-1998: Post doc on Signal transduction, University of York, UK
  • 1996: Ph.D. in Molecular biology, Swedish University Of Agricultural Sciences, Sweden
  • 1989: B.Sc. Biology/Chemistry, Uppsala University, Sweden

Positions

  • 2009-current: Professor (part time), Department of Forest Genetics and Plant Physiology, Swedish Agricultural University, Umeå, Sweden
  • 2016-current: Principal research Scientist, Georgia Institute of Technology, Atlanta, GA
  • 2008-2015: VINNMER Marie Curie Fellow, Georgia Institute of Technology, Atlanta, GA
  • 2006-2016: Project leader, SweTree Technologies
  • 2004-2008: Associate Professor of Genetics and Biotechnology, College of Natural Resources, Department of Forestry, Virginia Polytechnic Institute and State University, Blacksburg, VA
  • 2000-2003: Research Faculty, Institute of Paper Science and Technology, Atlanta, GA
  • 1998-2000: Senior Scientific Officer, Norwegian Forest Research Institute, Ås, Norway
  • 1989-1990: Research scientist, Genetic Center, Uppsala, Sweden
{tab=Publications}
  2023 (1)
In Vitro Propagation of the Blueberry ‘Blue Suede™’ (Vaccinium hybrid) in Semi-Solid Medium and Temporary Immersion Bioreactors. Le, K., Johnson, S., Aidun, C. K., & Egertsdotter, U. Plants, 12(15): 2752. July 2023. Number: 15 Publisher: Multidisciplinary Digital Publishing Institute
In Vitro Propagation of the Blueberry ‘Blue Suede™’ (Vaccinium hybrid) in Semi-Solid Medium and Temporary Immersion Bioreactors [link]Paper   doi   link   bibtex   abstract  
  2022 (2)
Accumulated effects of factors determining plant development from somatic embryos of Abies nordmanniana and Abies bornmuelleriana. Nielsen, U. B., Hansen, C. B., Hansen, U., Johansen, V. K., & Egertsdotter, U. Frontiers in Plant Science, 13. October 2022.
Accumulated effects of factors determining plant development from somatic embryos of Abies nordmanniana and Abies bornmuelleriana [link]Paper   link   bibtex   abstract  
Stipagrostis pennata (Trin.) De Winter Artificial Seed Production and Seedlings Multiplication in Temporary Immersion Bioreactors. Aghbolaghi, M. A., Dedicova, B., Sharifzadeh, F., Omidi, M., & Egertsdotter, U. Plants, 11(22): 3122. January 2022. Number: 22 Publisher: Multidisciplinary Digital Publishing Institute
Stipagrostis pennata (Trin.) De Winter Artificial Seed Production and Seedlings Multiplication in Temporary Immersion Bioreactors [link]Paper   doi   link   bibtex   abstract  
  2021 (5)
In silico characterization of putative gene homologues involved in somatic embryogenesis suggests that some conifer species may lack LEC2, one of the key regulators of initiation of the process. Ranade, S. S., & Egertsdotter, U. BMC Genomics, 22(1): 392. December 2021.
In silico characterization of putative gene homologues involved in somatic embryogenesis suggests that some conifer species may lack LEC2, one of the key regulators of initiation of the process [link]Paper   doi   link   bibtex   abstract   9 downloads  
Protocol development for somatic embryogenesis, SSR markers and genetic modification of Stipagrostis pennata (Trin.) De Winter. Asadi-Aghbolaghi, M., Dedicova, B., Ranade, S. S., Le, K., Sharifzadeh, F., Omidi, M., & Egertsdotter, U. Plant Methods, 17(1): 70. June 2021.
Protocol development for somatic embryogenesis, SSR markers and genetic modification of Stipagrostis pennata (Trin.) De Winter [link]Paper   doi   link   bibtex   abstract   2 downloads  
Scale-up of Somatic Embryogenesis Plant Production of Hybrid Larch (Larix x eurolepis) Using Temporary Immersion Bioreactors. Le, K., & Egertsdotter, U. In Vitro Cellular & Developmental Biology-Animal, 57(SUPPL 1): S38–S39. June 2021.
link   bibtex  
Sucrose-dependent production of biomass and low-caloric steviol glycosides in adventitious root cultures of Stevia rebaudiana (Bert.). Ahmad, N., Rab, A., Sajid, M., Ahmad, N., Fazal, H., Ali, M., & Egertsdotter, U. Industrial Crops and Products, 164: 113382. June 2021.
Sucrose-dependent production of biomass and low-caloric steviol glycosides in adventitious root cultures of Stevia rebaudiana (Bert.) [link]Paper   doi   link   bibtex   1 download  
Temporary immersion bioreactor system for propagation by somatic embryogenesis of hybrid larch (Larix × eurolepis Henry). Le, K., Dedicova, B., Johansson, S., Lelu-Walter, M., & Egertsdotter, U. Biotechnology Reports, 32: e00684. December 2021.
Temporary immersion bioreactor system for propagation by somatic embryogenesis of hybrid larch (Larix × eurolepis Henry) [link]Paper   doi   link   bibtex   abstract   1 download  
  2019 (5)
Automation and Scale Up of Somatic Embryogenesis for Commercial Plant Production, With Emphasis on Conifers. Egertsdotter, U., Ahmad, I., & Clapham, D. Frontiers in Plant Science, 10: 109. February 2019.
Automation and Scale Up of Somatic Embryogenesis for Commercial Plant Production, With Emphasis on Conifers [link]Paper   doi   link   bibtex   3 downloads  
Nitrogen utilization during germination of somatic embryos of Norway spruce: revealing the importance of supplied glutamine for nitrogen metabolism. Carlsson, J., Egertsdotter, U., Ganeteg, U., & Svennerstam, H. Trees, 33(2): 383–394. April 2019.
Nitrogen utilization during germination of somatic embryos of Norway spruce: revealing the importance of supplied glutamine for nitrogen metabolism [link]Paper   doi   link   bibtex   1 download  
Plant physiological and genetical aspects of the somatic embryogenesis process in conifers. Egertsdotter, U. Scandinavian Journal of Forest Research, 34(5): 360–369. July 2019.
Plant physiological and genetical aspects of the somatic embryogenesis process in conifers [link]Paper   doi   link   bibtex   3 downloads  
Using Norway spruce clones in Swedish forestry: implications of clones for management. Rosvall, O., Bradshaw, R. H., Egertsdotter, U., Ingvarsson, P. K., Mullin, T. J., & Wu, H. Scandinavian Journal of Forest Research, 34(5): 390–404. July 2019.
Using Norway spruce clones in Swedish forestry: implications of clones for management [link]Paper   doi   link   bibtex   1 download  
Using Norway spruce clones in Swedish forestry: introduction. Rosvall, O., Bradshaw, R. H., Egertsdotter, U., Ingvarsson, P. K., & Wu, H. Scandinavian Journal of Forest Research, 34(5): 333–335. July 2019.
Using Norway spruce clones in Swedish forestry: introduction [link]Paper   doi   link   bibtex  
  2018 (2)
Analysis of Nitrogen Utilization Capability during the Proliferation and Maturation Phases of Norway Spruce (Picea abies (L.) H.Karst.) Somatic Embryogenesis. Dahrendorf, J., Clapham, D., & Egertsdotter, U. Forests, 9(6): 288. May 2018.
Analysis of Nitrogen Utilization Capability during the Proliferation and Maturation Phases of Norway Spruce (Picea abies (L.) H.Karst.) Somatic Embryogenesis [link]Paper   doi   link   bibtex  
Improved and synchronized maturation of Norway spruce (Picea abies (L.) H.Karst.) somatic embryos in temporary immersion bioreactors. Mamun, N. H. A., Aidun, C. K., & Egertsdotter, U. In Vitro Cellular & Developmental Biology - Plant, 54(6): 612–620. December 2018.
Improved and synchronized maturation of Norway spruce (Picea abies (L.) H.Karst.) somatic embryos in temporary immersion bioreactors [link]Paper   doi   link   bibtex  
  2017 (4)
Evaluation of a New Temporary Immersion Bioreactor System for Micropropagation of Cultivars of Eucalyptus, Birch and Fir. Businge, E., Trifonova, A., Schneider, C., Rödel, P., & Egertsdotter, U. Forests, 8(6): 196. June 2017.
Evaluation of a New Temporary Immersion Bioreactor System for Micropropagation of Cultivars of Eucalyptus, Birch and Fir [link]Paper   doi   link   bibtex  
Histological analysis reveals the formation of shoots rather than embryos in regenerating cultures of Eucalyptus globulus. Dobrowolska, I., Andrade, G. M., Clapham, D., & Egertsdotter, U. Plant Cell, Tissue and Organ Culture (PCTOC), 128(2): 319–326. February 2017.
Histological analysis reveals the formation of shoots rather than embryos in regenerating cultures of Eucalyptus globulus [link]Paper   doi   link   bibtex  
Metabolome and transcriptome profiling reveal new insights into somatic embryo germination in Norway spruce (Picea abies). Dobrowolska, I., Businge, E., Abreu, I. N, Moritz, T., & Egertsdotter, U. Tree Physiology, 37(12): 1752–1766. December 2017.
Metabolome and transcriptome profiling reveal new insights into somatic embryo germination in Norway spruce (Picea abies) [link]Paper   doi   link   bibtex  
Nitrogen uptake and assimilation in proliferating embryogenic cultures of Norway spruce—Investigating the specific role of glutamine. Carlsson, J., Svennerstam, H., Moritz, T., Egertsdotter, U., & Ganeteg, U. PLOS ONE, 12(8): e0181785. August 2017.
Nitrogen uptake and assimilation in proliferating embryogenic cultures of Norway spruce—Investigating the specific role of glutamine [link]Paper   doi   link   bibtex  
  2016 (2)
DNA methylome of the 20-gigabase Norway spruce genome. Ausin, I., Feng, S., Yu, C., Liu, W., Kuo, H. Y., Jacobsen, E. L., Zhai, J., Gallego-Bartolome, J., Wang, L., Egertsdotter, U., Street, N. R., Jacobsen, S. E., & Wang, H. Proceedings of the National Academy of Sciences, 113(50): E8106–E8113. December 2016.
DNA methylome of the 20-gigabase Norway spruce genome [link]Paper   doi   link   bibtex   abstract  
Fraser fir somatic embryogenesis: high frequency initiation, maintenance, embryo development, germination and cryopreservation. Pullman, G. S., Olson, K., Fischer, T., Egertsdotter, U., Frampton, J., & Bucalo, K. New Forests, 47(3): 453–480. May 2016.
Fraser fir somatic embryogenesis: high frequency initiation, maintenance, embryo development, germination and cryopreservation [link]Paper   doi   link   bibtex  
  2015 (1)
Bioreactor technology for clonal propagation of plants and metabolite production. Mamun, N. H. A., Egertsdotter, U., & Aidun, C. K. Frontiers in Biology, 10(2): 177–193. April 2015. Section: 177
doi   link   bibtex  
  2014 (1)
A possible biochemical basis for fructose-induced inhibition of embryo development in Norway spruce (Picea abies). Businge, E., & Egertsdotter, U. Tree Physiology, 34(6): 657–669. June 2014.
A possible biochemical basis for fructose-induced inhibition of embryo development in Norway spruce (Picea abies) [link]Paper   doi   link   bibtex  
  2013 (1)
The effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce somatic embryos. Businge, E., Bygdell, J., Wingsle, G., Moritz, T., & Egertsdotter, U. Physiologia Plantarum, 149(2): 273–285. October 2013.
The effect of carbohydrates and osmoticum on storage reserve accumulation and germination of Norway spruce somatic embryos [link]Paper   doi   link   bibtex   1 download  
  2012 (2)
Comparison of gene expression markers during zygotic and somatic embryogenesis in pine. Lara-Chavez, A., Egertsdotter, U., & Flinn, B. S. In Vitro Cellular & Developmental Biology - Plant, 48(3): 341–354. June 2012.
Comparison of gene expression markers during zygotic and somatic embryogenesis in pine [link]Paper   doi   link   bibtex  
Metabolite profiling reveals clear metabolic changes during somatic embryo development of Norway spruce (Picea abies). Businge, E., Brackmann, K., Moritz, T., & Egertsdotter, U. Tree Physiology, 32(2): 232–244. February 2012.
Metabolite profiling reveals clear metabolic changes during somatic embryo development of Norway spruce (Picea abies) [link]Paper   doi   link   bibtex  
  2011 (3)
Initiation of somatic embryogenesis from immature zygotic embryos of Oocarpa pine (Pinus oocarpa Schiede ex Schlectendal). Lara-Chavez, A., Flinn, B. S., & Egertsdotter, U. Tree Physiology, 31(12): 1422–1422. December 2011.
Initiation of somatic embryogenesis from immature zygotic embryos of Oocarpa pine (Pinus oocarpa Schiede ex Schlectendal) [link]Paper   doi   link   bibtex  
Possible Effect From Shear Stress on Maturation of Somatic Embryos of Norway Spruce (Picea abies). Sun, H., Aidun, C. K., & Egertsdotter, U. Biotechnology and Bioengineering, 108(5): 1089–1099. May 2011.
Possible Effect From Shear Stress on Maturation of Somatic Embryos of Norway Spruce (Picea abies) [link]Paper   doi   link   bibtex  
Somatic embryogenesis for plant production of Abies lasiocarpa. Kvaalen, H., Daehlen, O. G., Rognstad, A. T., Grønstad, B., & Egertsdotter, U. Canadian Journal of Forest Research. February 2011. Publisher: NRC Research Press Ottawa, Canada
Somatic embryogenesis for plant production of Abies lasiocarpa [link]Paper   doi   link   bibtex   abstract  
  2010 (1)
Effects from shear stress on morphology and growth of early stages of Norway spruce somatic embryos. Sun, H., Aidun, C. K., & Egertsdotter, U. Biotechnology and Bioengineering, 105(3): 588–599. February 2010.
Effects from shear stress on morphology and growth of early stages of Norway spruce somatic embryos [link]Paper   doi   link   bibtex  
  2008 (1)
Lignin biosynthesis in transgenic Norway spruce plants harboring an antisense construct for cinnamoyl CoA reductase (CCR). Wadenbäck, J., von Arnold, S., Egertsdotter, U., Walter, M. H., Grima-Pettenati, J., Goffner, D., Gellerstedt, G., Gullion, T., & Clapham, D. Transgenic Research, 17(3): 379–392. June 2008.
Lignin biosynthesis in transgenic Norway spruce plants harboring an antisense construct for cinnamoyl CoA reductase (CCR) [link]Paper   doi   link   bibtex  
  2005 (1)
Comparison of standard exponential and linear techniques to amplify small cDNA samples for microarrays. Wadenbäck, J., Clapham, D. H., Craig, D., Sederoff, R., Peter, G. F., von Arnold, S., & Egertsdotter, U. BMC Genomics, 6(1): 61. May 2005.
Comparison of standard exponential and linear techniques to amplify small cDNA samples for microarrays [link]Paper   doi   link   bibtex   abstract  
  2004 (2)
Gene Expression during Formation of Earlywood and Latewood in Loblolly Pine: Expression Profiles of 350 Genes. Egertsdotter, U., Zyl, L. M. v., MacKay, J., Peter, G., Kirst, M., Clark, C., Whetten, R., & Sederoff, R. Plant Biology, 6(6): 654–663. 2004. _eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1055/s-2004-830383
Gene Expression during Formation of Earlywood and Latewood in Loblolly Pine: Expression Profiles of 350 Genes [link]Paper   doi   link   bibtex   abstract  
Variation in transcript abundance during somatic embryogenesis in gymnosperms. Stasolla, C., Bozhkov, P. V., Chu, T., van Zyl, L., Egertsdotter, U., Suarez, M. F., Craig, D., Wolfinger, R. D., Von Arnold, S., & Sederoff, R. R. Tree Physiology, 24(10): 1073–1085. October 2004. Publisher: Oxford Academic
Variation in transcript abundance during somatic embryogenesis in gymnosperms [link]Paper   doi   link   bibtex   abstract  
  2003 (4)
Analysis of lignin produced by cinnamyl alcohol dehydrogenase-deficient Pinus taeda cultured cells. Stasolla, C., Scott, J., Egertsdotter, U., Kadla, J., O’ Malley, D., Sederoff, R., & van Zyl, L. Plant Physiology and Biochemistry, 41(5): 439–445. May 2003.
Analysis of lignin produced by cinnamyl alcohol dehydrogenase-deficient Pinus taeda cultured cells [link]Paper   doi   link   bibtex   abstract  
Photosynthetic Acclimation Is Reflected in Specific Patterns of Gene Expression in Drought-Stressed Loblolly Pine. Watkinson, J. I., Sioson, A. A., Vasquez-Robinet, C., Shukla, M., Kumar, D., Ellis, M., Heath, L. S., Ramakrishnan, N., Chevone, B., Watson, L. T., van Zyl, L., Egertsdotter, U., Sederoff, R. R., & Grene, R. Plant Physiology, 133(4): 1702–1716. December 2003.
Photosynthetic Acclimation Is Reflected in Specific Patterns of Gene Expression in Drought-Stressed Loblolly Pine [link]Paper   doi   link   bibtex   abstract  
The Effects of Polyethylene Glycol on Gene Expression of Developing White Spruce Somatic Embryos. Stasolla, C., van Zyl, L., Egertsdotter, U., Craig, D., Liu, W., & Sederoff, R. R. Plant Physiology, 131(1): 49–60. January 2003.
The Effects of Polyethylene Glycol on Gene Expression of Developing White Spruce Somatic Embryos [link]Paper   doi   link   bibtex   abstract   1 download  
Transcript profiles of stress-related genes in developing white spruce (Picea glauca) somatic embryos cultured with polyethylene glycol. Stasolla, C., van Zyl, L., Egertsdotter, U., Craig, D., Liu, W., & Sederoff, R. R. Plant Science, 165(4): 719–729. October 2003.
Transcript profiles of stress-related genes in developing white spruce (Picea glauca) somatic embryos cultured with polyethylene glycol [link]Paper   doi   link   bibtex   abstract  
  2002 (2)
A promoter from the loblolly pine PtNIP1;1 gene directs expression in an early-embryogenesis and suspensor-specific fashion. Ciavatta, V. T., Egertsdotter, U., Clapham, D., von Arnold, S., & Cairney, J. Planta, 215(4): 694–698. August 2002.
A promoter from the loblolly pine PtNIP1;1 gene directs expression in an early-embryogenesis and suspensor-specific fashion [link]Paper   doi   link   bibtex   abstract  
Heterologous Array Analysis in Pinaceae: Hybridization of Pinus taeda cDNA Arrays with cDNA from Needles and Embryogenic Cultures of P. taeda, P. sylvestris or Picea abies. van Zyl, L., von Arnold, S., Bozhkov, P., Chen, Y., Egertsdotter, U., MacKay, J., Sederoff, R. R., Shen, J., Zelena, L., & Clapham, D. H. Comparative and Functional Genomics, 3(4): 306–318. 2002. Publisher: Hindawi
Heterologous Array Analysis in Pinaceae: Hybridization of Pinus taeda cDNA Arrays with cDNA from Needles and Embryogenic Cultures of P. taeda, P. sylvestris or Picea abies [link]Paper   doi   link   bibtex   abstract  
{tab=Svenska}Ulrika Egertsdotter i ett tillväxtrum med växter som förökas genom somatisk embryogenes

Somatisk embryogenes är en in vitro teknik som kan användas för massförökning av zygotiska embryon, dvs fröembryon, från barrträd. Det är den enda teknik som lämpar sig för storskalig massförökning av plantor från värdefulla granfrön framtagna i förädlings-programmet.

Somatiska embryon, eller frösticklingar, används också för att studera reglering av embryoutveckling då man kan framställa obegränsade mängder embryon av olika utvecklingsstadier som försöksmaterial. Vi är intresserade av signalsubstanserna som reglerar embryo utvecklingen och vidare undersöka signaltransduktionsvägarna. Vi har nyligen visat att etxracellulära metalloproteaser har betydelse för embryoutvecklingen och fokuserar nu vidare på överföringen av extracellulära signaler till specifika cellulära responser.