查看文章

Norway spruce (Picea abies) is a dominant tree species in boreal forests with extensive ecological and economic value. Climate change is threatening these ecosystems, with rising temperatures impacting cold hardening and increasing drought stress in regions experiencing lower precipitation. Increasing atmospheric CO 2 concentrations and nitrogen deposition can, in contrast, partially offset such negative effects by improving tree growth and carbon uptake. Similar to aboveground carbon fixation, carbon sequestration in boreal soils is important. Bacteria and fungi mineralize organic matter and, by making nutrients available for plants, are important for tree health. The ability of Norway spruce and the associated microbiota to adapt to climate change is of fundamental importance for ecosystem functioning and is the focus of this thesis.

Norway spruce seedlings were subjected to cold or drought stress and the transcriptional response compared to known mechanisms in the model plant Arabidopsis thaliana. Analyses revealed that while there was overlap in the stress responses between species, including increased osmotic and oxidative stress tolerance, the majority of differentially expressed genes were stress-responsive only in Norway spruce. Importantly, transcription factors of the abscisic acid dependent and independent pathways were not differentially expressed or were missing homolog sequences in Norway spruce, indicating that different regulatory pathways are active in Norway spruce and suggesting that stress response has evolved differently in the species. Furthermore, differential gene expression in roots differed extensively from …