Gene expression in Arabidopsis thaliana leaves after chilling and/or herbivory by Pieris brassicae or Mamestra brassice larvae or after mechanical wounding

To investigate the impact of a plant´s response to abiotic stress on plant defense against subsequent biotic stress, we determined the transcriptional response of Arabidopsis thaliana to low temperature stress (4°C) and subsequent mechanical wounding or larval feeding damage by the herbivores Mamestra brassicae (generalist) and Pieris brassicae (specialist). In total, 21%, 4% and 14% of all genes responsive to M. brassicae, P. brassicae or mechanical wounding were differentially regulated in previously cold-treated compared to untreated plants. Arabidopsis thaliana Col-0 wild type plants were grown under short day conditions (8 h/16 h light/dark) at 20°C for 7 weeks. Subsequently (i) the plants were transferred to 4°C for 5 days or (ii) as controls plants grew untreated for five days. Next, the chilling treated plants were transferred back to 20°C and all plants rested for 1 day at 20°C. Next, P. brassicae or M. brassicae larvae were allowed to feed for 2 days, or mechanical wounding was applied two times per day on leaf 17 at a respective leaf region of chilling-treated or untreated plants. Control plants were not exposed to larvae. From all treated and untreated plants material from leaf 17, next to feeding/ wounding sites was harvested for transcriptome analysis.