(E)-2-Hexenal-based coating induced acquired resistance in apple and its antifungal effects against Penicillium expansum
Xianghua Wang, Maorun Fu, Xiaoqian Qu, Jingjing Liu, Jianwen Bu, Shaoran Feng, Handong Zhao, Wenxiao Jiao, Fei Sun
Abstract
(E)-2-Hexenal is one of the most prevalent and abundant volatile substances in fruits. Many researchers have attempted fumigation with (E)-2-hexenal to control fungal diseases with poor or no results; the key is the inability to maintain an effective concentration for a long time. Therefore, a new starch-based antifungal coating with (E)-2-hexenal microcapsules was prepared. The obtained results showed that the microcapsule embedding rate reached 78.95% by orthogonal optimization experiments and that the (E)-2-hexenal-based coating was effective at reducing the lesion diameter of apple fruit during storage at 25 °C after Penicillium expansum infection, and in other fruits; it also achieved a good antifungal effect. Moreover, the activities of the main defense-related enzymes and the expression of key genes involved in the salicylic acid (SA) signaling pathway, such as CHI, GLU, PAL, NPR1, and PR1, were enhanced by (E)-2-hexenal-based coating treatment. These findings suggest that the (E)-2-hexenal-based coating has the dual effect of direct antifungal and induction of apple system resistance. E2H-based coating is a promising approach to control postharvest Penicillium expansum in fruit.