Acibenzolar- S -methyl and probenazole activate stomatal-based defense at different times to control bacterial blight of cabbage

In efforts to control bacterial blight caused by Pseudomonas cannabina pv. alisalensis (Pcal) on cabbage using plant defense activators acibenzolar-S-methyl (ASM) and probenazole (PBZ), a soil drench with ASM and PBZ effectively suppressed Pcal lesion formation and reduced bacterial populations compared with a water drench. Although ASM and PBZ activated stomatal-based defense against Pcal resulting in lower bacterial populations and less-severe symptoms, ASM, but not PBZ, induced stomatal-based defense within 4 h after the soil drench. Thus, ASM and PBZ activate a stomatal-based defense in cabbage against Pcal but differ the timing of induction.