Small RNA sequencing from Arabidopsis adult leaves and profiling of Arabidopsis transcripts in response to flg22 peptide

DNA methylation is an epigenetic mark that silences transposable elements (TEs) and repeats. Whereas the establishment and maintenance of DNA methylation are relatively well understood, little is known on their dynamics and biological relevance in plant and animal innate immunity. Here, we show that some TEs are demethylated and transcriptionally reactivated during antibacterial defense in Arabidopsis. This effect is concomitant with the down-regulation of key transcriptional gene silencing factors as well as an active demethylation process. DNA demethylation restricts multiplication and vascular propagation of the bacterial pathogen Pseudomonas syringae in leaves and, accordingly, some immune-response genes, containing repeats in their promoters, are negatively regulated by DNA methylation. This study provides evidence that DNA demethylation is part of a plant-induced immune response, potentially acting to prime transcriptional activation of some defense genes linked to Tes/repeats. We have monitored the transcript changes in Arabidopsis plants treated with a flagellin-derived peptide. Overall design: DNA methylation is closely related to 24nt sRNAs. This is why we sequenced small RNA population in our study. 5-week-old Col-0 leaf samples (treated with either water or flg22 at 1 ?M concentration for 6 h) and deep sequenced by Fasteris (Geneva) on the Illumina HiSeq 2000 platform.

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Yu A, Lepère G, Jay F, Wang J, Bapaume L, Wang Y, Abraham AL, Penterman J, Fischer RL, Voinnet O, Navarro L