Induction of systemic resistance to Colletotrichum falcatum in sugarcane by a synthetic signal molecule, acibenzolar-S-methyl (CGA-245704)

The effect of a novel synthetic signal molecule, acibenzolar-S-methyl (CGA- 245704; benzo [1,2,3] thiadiazole-7-carbothioic acid S-methyl ester), in in ducing resistance in sugarcane against red rot disease caused by the fungus Colletotrichum falcatum Went was studied. Application of CGA-245704 as a s oil drench or along with marcotting rooting mixture induced resistance in s ugarcane to challenge inoculation with C. falcatum. When the pathogen was i noculated by the plug method, it caused discoloration in the untreated cont rol stalk tissues; however, in the stalk tissues pretreated with acibenzola r-S-methyl, pathogen colonization was considerably reduced. When the pathog en was inoculated by nodal swabbing, its penetration was arrested in the se nsitized stalk tissues. An induced systemic resistance effect was found to persist up to 30 days in the pretreated cut canes. Increased phenolic conte nt and accumulation of pathogenesis-related (PR) proteins, viz., chitinase, beta -1,3-glucanase and thaumatin-like protein (PR-5), were observed in su garcane plants treated with acibenzolar-S-methyl.