Biocontrol of Gray Mold of Cherry Tomatoes with the Volatile Organic Monomer from Hanseniaspora uvarum, Trans-Cinnamaldehyde

Abstract

Botrytis cinerea is one of the most destructive pathogens of cherry tomatoes during preharvest and postharvest phase. Our previous study demonstrated that volatile organic compounds (VOCs) produced by Hanseniaspora uvarum could markedly suppress the mycelium growth and conidia germination of B. cinerea. However, the main inhibitory VOCs of H. uvarum are not fully clear. In this study, a total of 21 volatile organic monomers (VOMs) of H. uvarum were tested for their antifungal activity against B. cinerea in vitro. It was found that trans-cinnamaldehyde, 2-nonanone, ethyl caprylate, benzyl alcohol, hexanoic acid, hexyl alcohol, isobutyl acetate, ethyl propionate, isoamyl acetate, ethyl 2-methylbutyrate, phenethyl alcohol, ethyl acetate, 4-ethylphenol, 3-phenyl-1-propanol, ethyl cinnamate, 3-methyl-1-butanol, and ethyl 3-hydroxybhexanoate could significantly inhibit mycelium growth within 3 days at higher concentrations, whereas ethyl 3-hydroxybutyrate, ethyl caprate, decanoic acid, and lauric acid exhibited a lower inhibition. Furthermore, the five VOMs, including trans-cinnamaldehyde, 2-nonanone, ethyl caprylate, benzyl alcohol, and hexanoic acid, also had the efficiency on inhibiting conidia germination. In particular, trans-cinnamaldehyde was the best inhibitor of mycelium growth and conidia germination. Hence, trans-cinnamaldehyde was also tested in vivo as postharvest biofumigants. In vivo assay showed that trans-cinnamaldehyde could significantly reduce B. cinerea infection of cherry tomatoes and maintain fruit hardness, color, total soluable solids, and titratable acidity under conditions of artificial and natural infection. Collectively, these results indicated that trans-cinnamaldehyde, the main inhibitory VOMs of H. uvarum, has the potential for effectively controlling postharvest gray mold of cherry tomatoes and maintaining fruit quality in commercial application.