Induction of bacterial blight (Xanthomonas oryzae pv. oryzae) resistance in rice by treatment with acibenzolar-S-methyl

Summary The role of the plant defence activator, acibenzolar‐S‐methyl (ASM), in inducing resistance in rice against bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (Xoo) was studied. Application of ASM induced resistance in rice to infection by Xoo. When the pathogen was clip‐inoculated to the rice plants, it caused bacterial leaf blight symptoms in the untreated control. However, in the rice plants pretreated with ASM, infection was significantly reduced. Induced systemic resistance was found to persist for up to 3 days in the pretreated rice plants. Increased phenolic content and accumulation of pathogenesis‐related (PR) proteins, viz. chitinase, β‐1,3‐glucanase and thaumatin‐like protein (TLP; PR 5) were observed in rice plants pretreated with ASM followed by inoculation with Xoo. Immunoblot analysis using rice TLP and tobacco chitinase antiserum revealed rapid induction and over‐expression of 25 and 35 kDa TLP and chitinase, respectively, in rice in response to pretreatment with ASM followed by Xoo inoculation. Based on these experiments, it is evident that induction of disease resistance in rice was accelerated following treatment with ASM.