Postharvest treatment with trans-2-hexenal induced resistance against Botrytis cinerea in tomato fruit

Trans-2-hexenal is a biocidal molecule released in many fruits and vegetables. In this paper, the effects of trans-2-hexenal on the control of postharvest diseases in tomato fruits were investigated. We indicated that the incidence of natural infection and infection by Botrytis cinerea in tomato fruits was significantly decreased after treatment with trans-2-hexenal. Trans-2-hexenal increased the mRNA levels of genes encoding ethylene receptors, lipoxygenase and phenylalanine ammonia lyase (PAL), but did not induce the mRNA accumulation of the pathogenesis-related proteins, such as PR-1a or PR-5. The activities of peroxidases and PAL and the accumulation of phenolic compounds were significantly enhanced after trans-2-hexenal treatment. This is the first report of trans-2-hexenal as an elicitor and its ability to control the postharvest diseases in tomato fruits. These results suggest that the controlling effects of trans-2-hexenal on both natural infection and gray mould in tomato fruits might be related to JA/ET-mediated induced systemic resistance.