Transcriptome analysis in systemic leaves of Arabidopsis thaliana locally inoculated with Pseudomonas syringae pv tomato DC3000 AvrRpm1
Defense activation at local pathogen challenged leaves leads to systemic acquired resistance (SAR) with defense-related genes primed for a subsequent stimulus at distal unchallenged (systemic) leaves. Our previous studies implied the possible involvements of transcription-permissive histone modification H3K4me3 and transcription-repressive H3K27me3 in systemic immunity. Our studies found that ATX1 (responsible for H3K4me3 deposition) and CLF-PRC2 (responsible for H3K27me3 deposition) both contribute to systemic defense priming and SAR. Consistent with this, H3K4me3 levels were increased in defense-related genes in a CLF-dependent manner. H3K4me3 deposition often follows changes in the transcriptional status of the target loci. To examine whether priming target genes were induced in systemic leaves before getting primed, we conducted RNA-seq analysis in systemic leaves of Arabidopsis thaliana WT Col-0 and clf-28 plants. Plants were locally inoculated with Pseudomonas syringae pv tomato AvrRpm1 or mock, and non-challenged systemic leaves were harvested at 0, 6, 8 and 24 hours after bacterial inoculation and subjected to RNA-seq analysis.