The Arabidopsis active demethylase ROS1 < i > cis < /i > -regulates defense genes by erasing DNA methylation at promoter-regulatory regions

Active DNA demethylation has emerged as an important regulatory process of plant and mammalian immunity. However, very little is known about the mechanisms by which active demethylation controls transcriptional immune reprogramming and disease resistance. Here, we first show that the Arabidopsis active demethylase ROS1 promotes basal resistance towardsPseudomonas syringae by antagonizing RNA-directed DNA methylation (RdDM). Furthermore, we find that ROS1 facilitates the flagellin-triggered induction of the disease resistance geneRMG1by limiting RdDM at the 3' boundary of a remnant RC/Helitron transposable element (TE) embedded in its promoter. We further identify flagellin-responsive ROS1 putative primary targets, and show that at a subset of promoters, ROS1 erases methylation at discrete regions exhibiting WRKY transcription factors (TFs) binding. In particular, we demonstrate that ROS1 removes methylation at the orphan immune receptorRLP43 promoter, to ensure DNA binding of WRKY TFs. Finally, we show that ROS1-directed demethylation of theRMG1 andRLP43 promoters is causal for both flagellin responsiveness of these genes and for basal resistance. Overall, these findings significantly advance our understanding of how active demethylases shape transcriptional immune reprogramming to enable antibacterial resistance.
Source: eLife - Category: Biomedical Science Tags: Genetics and Genomics Plant Biology Source Type: research