Transcription profiling of WT and dsr1 Arabidopsis seedlings treated with salicylic acid

Reactive oxygen species such as hydrogen peroxide (H2O2) are important in biotic and abiotic stress responses in plants, but their source is often unclear. We have identified an Arabidopsis mutant that shows loss of stress responsive GSTF8 gene expression in response to the plant defence signal salicylic acid (SA) . The mutant showed increased susceptibility to both fungal and bacterial pathogens. The dsr1 mutation was mapped to mitochondrial succinate dehydrogenase (SDH1-1) and dsr1 had reduced SDH activity and a lowered mitochondrial H2O2 production. To better understand the loss of SA-response in dsr1, we performed ATH1 microarray analysis in WT and dsr1 10 hours after a 1 mM SA treatment, a point at which we observed maximal SA-induced GSTF8 promoter activity. 4 day old WT (a Columbia line containing a -800GSTF8::LUC reporter) and dsr1 seedlings (a mutant Columbia line containing a -800GSTF8::LUC) reporterwere treated with water (mock) or 1 mM SA for 40 min. Ten hours after treatment, samples were collected.