Foliar application of Methyl Jasmonate Methyl Ester elicits differential antioxidant defence and expression of defence‐related genes against early blight disease of tomato.

Phytohormones are the key regulators of various developmental and physiological processes in plants. In the present study, we have examined the efficacy of Methyl Jasmonate Methyl Ester (MJME) as a potent elicitor on inducing resistance factors against early blight disease of tomato. Both PKM1 (susceptible) and Arka Rakshak (resistant) cultivars of tomato were sprayed with different concentrations of MJME (1, 5, 10 and 25 μM) and/or infected with A. solani. MJME pre‐treatment followed by A. solani infected leaves showed a higher accumulation of superoxide anion radicals and hydrogen peroxide at the early stages and then decreased gradually in both resistant and susceptible cultivars. A significant increase in antioxidant enzyme activity such as superoxide dismutase, guaiacol peroxidase and catalase was evident in MJME pre‐treatment followed by A. solani infected leaves in susceptible cultivar of tomato compared with control. Manifestation of disease symptoms was reduced to 60% in tomato leaves pre‐treated with higher concentrations of MJME and infected with A. solani in susceptible cultivar on par with resistant cultivar. Quantitative real‐time polymerase chain reaction (qRT‐PCR) analysis revealed an induction of expression of defence‐related genes such as ACO1, EDS1, LoxD, NP24, NPR1 and Sl10EAH30 in tomato leaves pre‐treated with MJME followed by A. solani infection. Interestingly, a two‐fold increase in the expression of EDS1 gene was evident in both susceptible and resistant cultivars after MJME treatment compared with control. The present study showed that MJME could be a potential elicitor of resistance factors against the early blight disease of tomato. [ABSTRACT FROM AUTHOR]