INDUCTION OF DISEASE RESISTANCE AND ANTIOXIDANT ENZYMES BY ACIBENZOLARSMETHYL AGAINST BACTERIAL CANKER CLAVIBACTER MICHIGANENSIS SUBSP MICHIGANENSIS IN TOMATO
E.M. Soylu, S. Soylu, Ö. Baysal
The plant defence activator acibenzolar-S-methyl (Bion) was assayed on tomato seedlings for its ability to induce multicomponent defence response against Clavibacter michiganensis subsp. michiganensis (Cmm). Pretreatment of plants with ASM reduced the severity of the disease as well as the growth of the bacteria in planta. In ASM-treated plants, reduction in disease severity (up to 75%) was correlated with the suppression of bacterial growth (up to 68.2%) during the time course of infection. In plants treated with ASM, activities of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione S-transferase (GST) were estimated as markers of resistance. The results indicated that ASM treatment led to enhanced activities of SOD and GST in tomato leaves. A slightly increase in SOD and GST activities was also found in Cmm-infected leaves. However, the increase in enzyme activities occurred much more rapidly and was more strongly enhanced in Cmminfected leaves that were previously treated with ASM. The involvement of both enzymes in ASM mediated resistance in tomato is discussed.