Antifungal Activity of Volatile Organic Compounds Produced byBacillus methylotrophicusandBacillus thuringiensisagainst Five Common Spoilage Fungi on Loquats

Loquat fruit is one of the most perishable fruits in China, and has a very limited shelf life because of mechanical injury and microbial decay. Due to an increasing concern about human health and environmental security, antagonistic microorganisms have been a potential alternative for fungicides to control postharvest diseases. In this work, the antifungal effect of volatile organic compounds (VOCs) produced byBacillus methylotrophicusBCN2 andBacillus thuringiensisBCN10 against five postharvest pathogens isolated from loquat fruit,Fusarium oxysporum,Botryosphaeriasp.,Trichoderma atroviride,Colletotrichum gloeosporioides,andPenicillium expansumwere evaluated by in vitro and in vivo experiments. As a result, the VOCs released by BCN2 and BCN10 were able to suppress the mycelial growth of all targeted pathogens according to inhibition ratio in the double petri-dish assay as well as disease incidence and disease diameter on loquat fruits. The main volatile compounds were identified by solid-phase microextraction (SPME)-gas chromatography. These VOCs produced by the two strains played complementary roles in controlling these five molds and enabled loquat fruits to keep fresh for ten days, significantly. This research will provide a theoretic foundation and technical support for exploring the functional components of VOCs applicable in loquat fruit preservation.