The impact of cold priming on the alerting phase of light and cold regulation of gene expression in Arabidopsis thaliana. The impact of cold priming on the alerting phase of light and cold regulation of gene expression in Arabidopsis thaliana

We analysed the effect of a short 24 hours cold exposure (priming-stimulus) on gene regulation upon the first two hours of a second cold (4°C) stimulus (cold-triggering) and upon the first two hours of excess light exposure (800 µmol photons m-2 s-1, light triggering). The first and the second stress treatment was seperated by 5 days long lag-phase, which is long enough to reset most of the primary stress response. Several early light and early cold responsive genes showed however a altered transcript abundance in plants, which received five days befor the cold priming stimulus. Espicially JA responsive genes showed a common priming regulation within the cold and light exposure. Overall design: Transcript levels were assessed in a transcriptome wide scale by peired end next generation sequencing (BGI-Seq-500). Half of the 4-week old Arabidopsis thaliana Col-0 plants were primed for 24 hours at 4 °C (cold-priming) and than retransferred to control conditions for addiotinal 5 days. Than rosette tissue of 20 % of the cold-primed and control non-primed plants were harvested two hours after the onset of the light period. The remaining 80% were split into two groups were either treated with second cold stimulus (4 °C) or were exposed to a 8-fold higher light intensity applied by heat-filtered halogen lamps. The cold treated and light treated plants were harvested after 30-, 60-, and 120 min of stress exposure. For each sample leave tissue of at least 5 plants were pooled and combined for cDNA library construction.