The rice OsERF101 transcription factor regulates the NLR Xa1-mediated immunity induced by perception of TAL effectors

Plant nucleotide-binding leucine-rich repeat receptors (NLRs) initiate immune responses by recognizing pathogen effectors. The rice gene Xa1 encodes an NLR with an N-terminal BED domain, and recognizes transcription activator-like (TAL) effectors of Xanthomonas oryzae pv. oryzae (Xoo). Our goal is to elucidate the molecular mechanisms controlling the induction of immunity by Xa1. We used yeast two-hybrid assays to screen for host factors that interact with Xa1 and identified the AP2/ERF-type transcription factor OsERF101/OsRAP2.6. Molecular complementation assays were used to confirm the interactions among Xa1, OsERF101, and two TAL effectors. We created OsERF101-overexpressing and knockout mutant lines in rice and identified genes differentially regulated in these lines, many of which are predicted to be involved in regulation of response to stimulus. Xa1 interacts in the nucleus with the TAL effectors and OsERF101 via the BED domain. Unexpectedly, both the overexpression and knockout lines of OsERF101 displayed Xa1-dependent, enhanced resistance to an incompatible Xoo strain. Different sets of genes were up- or down-regulated in the overexpression and knockout lines. Our results indicate that OsERF101 regulates the recognition of TAL effectors by Xa1, and functions as a positive regulator of Xa1-mediated immunity. Further, an additional Xa1-mediated immune pathway is negatively regulated by OsERF101.
イネが病原菌の感染力の源を検出して免疫を誘導する仕組みを解明 --病気に強い植物の開発に期待--. 京都大学プレスリリース. 2022-09-07.