Bacteria suppress immune responses in Arabidopsis by inducing methylglyoxal accumulation and promoting H2O2 scavenging

Abstract

Various reactive small molecules, naturally produced via cellular metabolism, function in plant immunity. However, how pathogens use plant metabolites to promote their infection is poorly understood. Here, we identified that infection with a virulent bacterial strain represses glyoxalase I (GLYI) activity, leading to elevated levels of methylglyoxal (MG) in Arabidopsis. Genetic analysis of GLYIs further supports that MG promotes bacterial infection. Mechanistically, MG modifies TRIPHOSPHATE TUNNEL METALLOENZYME2 (TTM2) at Arg-351, facilitating its interaction with CATALASE2 (CAT2), resulting in higher CAT2 activity and lower hydrogen peroxide (H₂O₂) accumulation. Taken together, we demonstrate that the bacterial pathogen harnesses the plant metabolite MG to promote its infection by scavenging H₂O₂.