Mutation in Arabidopsis ?-cyanoalanine synthase overcomes NADPH oxidase action in response to pathogens

Abstract Plant responses to pathogens comprise a complex process, implying plethora of signals and reactions. Among them, endogenous production hydrogen cyanide (HCN) has been shown induce resistance in Arabidopsis the hemibiotrophic bacterium Pseudomonas syringae pv. tomato (Pst) DC3000. ?-cyanoalanine synthase (CAS-C1) is responsible for detoxification HCN mitochondria. Here, we show that green fluorescent protein-tagged CAS-C1 transiently reduced leaves infected with an avirulent strain Pst during early interactions increased virulent Pst, supporting previous transcriptional data. Genetic crosses mutation resembles action NADPH oxidase RbohD independently reactive oxygen species accumulation salicylic acid required HCN-stimulated Pst. Finally, cas-c1 acts on acid-dependent response by mechanisms other than protein ubiquitination or increase monomerization entry nucleus NPR1, central regulator acid-mediated response. Considering these results, propose new modulation immune HCN.