Norway Spruce seedlings growing in the greenhouse (photo: Sonali Ranade)
[2021-02-01] Sweden is a country with big differences in light conditions between the South and the North. Norway spruce tolerates low light or shade generally well but Sonali Ranade and Rosario García-Gil from UPSC showed now that there are latitudinal differences. Seedlings from Northern Sweden are better adapted to low light conditions than seedlings from Southern Sweden. This genetic adaptation seems to come along with a higher resistance to diseases. The results were published last week in the journal Planta.
The researchers from UPSC compared the growth of Norway spruce seedlings that derive from different latitudes in Sweden and showed that the seedlings from the north were better adapted to shady conditions than the ones from the south. When analysing the genetic set-up of the different trees, they found, among other, differences in genes involved in lignin and cell wall synthesis, in stress responses and immunity. The two researchers concluded that the northern Norway spruce populations have not only adapted to low light conditions but might be also more resistant to diseases.
“Shade causes stress to most plants. They try to grow towards light so that they can use the full light energy for their photosynthesis,” says Sonali Ranade, postdoctoral researcher in Rosario García-Gil’s research group. “In a previous study, we saw that Norway spruce seedlings are more shade tolerant than for example Scots pine seedlings. Now, we realized that this is not so simple. The seedlings from the north developed longer stems than the seedlings in the south when growing under shady conditions. This shows that Norway spruce is able to adapt to local light conditions and we think that this goes along with modifications of the lignin metabolism.”
The lignin content often decreases when plants are exposed to low light conditions and this weakens the stem. Lignin is one of the main components in cell walls and helps to make the walls stronger allowing the plant to grow upright. In the cell walls, lignin also provides a barrier for pathogens to enter the cells. By scaling up lignin and cell wall biosynthesis and in parallel activating defence related genes, the northern Norway spruce populations might be able to adapt to shady conditions and in parallel improve their resistance to diseases.
“Studying the genetic diversity of trees from the same species help us to understand how plants adapt to local climatic conditions”, explains Rosario García-Gil, group leader at the Department of Forest Genetics and Plant Physiology at the Swedish University of Agricultural Sciences that is part of UPSC. “In Northern Sweden, the trees experience extended periods of shade-like conditions during their growing season. Climate change might lead to higher temperatures, but the light conditions will not change. To know the genetic factors that allow trees to adapt to the local conditions is crucial for forest breeding.”
Norway spruce is one of the most important tree species for forest industry in Sweden. To find the best adapted trees for a certain location is one forest management strategy to deal with climate change. Genetic markers like the genes identified in this study are used as tools to characterize different tree variants. The long-term goal is to identify as many marker genes as possible for a wide range of environmental conditions, including for example light, temperature and resistance to diseases. This will allow to design forest management strategies specifically adjusted to the local conditions.
About the article:
Ranade, S.S., García-Gil, M.R. Molecular signatures of local adaptation to light in Norway spruce. Planta 253, 53 (2021). https://doi.org/10.1007/s00425-020-03517-9
The previous study:
Ranade, S.S., Delhomme, N. & García-Gil, M.R. Transcriptome analysis of shade avoidance and shade tolerance in conifers. Planta 250, 299–318 (2019). https://doi.org/10.1007/s00425-019-03160-z
For more information, please contact:
Sonali Ranade
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Email:
María Rosario García-Gil
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Email:
https://www.upsc.se/rosario_garcia