Antifungal activity of volatile compounds from Bacillus tequilensis XK29 against Botrytis cinerea causing gray mold on cherry tomatoes

Botrytis cinerea is a necrotrophic fungal pathogen that causes gray mold disease in more than 1400 plant species. The biocontrol effect of microbial volatile compounds on postharvest diseases has become a research hotspot. This study revealed the biocontrol effects of volatiles released by Bacillus tequilensis XK29 on B. cinerea in vitro and in vivo. The results showed that the strain XK29 volatiles inhibited the mycelial growth of B. cinerea. The inhibition effect of strain XK29 volatiles against B. cinerea was increased by optimizing the wheat seeds weight, suspension concentration and inoculation volume of strain XK29, and the pre-culture time. The volatiles of strain XK29 affected the mycelial development, the formation of conidia, and the metabolic activity of B. cinerea. Selected individual monomers and artificial mixtures showed strong antifungal activity against B. cinerea. The volatiles of strain XK29 reduced the lesion diameter and disease severity of cherry tomatoes after inoculation with B. cinerea. These results indicate that the fumigation with B. tequilensis XK29 volatiles is a promising approach to protect cherry tomatoes from gray mold disease. This is also the first study to prove the antifungal effect of B. tequilensis on B. cinerea and its biocontrol effect on postharvest cherry tomatoes.