Aureobasidium pullulans S2 controls tomato gray mold and produces volatile organic compounds and biofilms

Gray mold emergence is detrimental to the production, transportation, and storage of tomatoes. The application of antagonistic microorganisms to control fruit diseases is a potential alternative to fungicides. This study investigated the effect of Aureobasidium pullulans S2 on controlling gray mold in tomatoes and explored the possible mechanisms. The results demonstrated that A. pullulans S2 effectively controlled the incidence of gray mold in tomatoes. The response of Botrytis cinerea to different components of the A. pullulans S2 culture showed that live yeast cells had B. cinerea inhibition ability. Environmental adaptability, host resistance induction, biofilm formation and production of volatile organic compounds (VOCs) with antimicrobial effects could also be important mechanisms of action of A. pullulans S2. The VOCs were identified, among which 2-phenylethanol, 2-heptanol and acetic acid, octyl ester could play an important role in B. cinerea inhibition. Ultimately, A. pullulans S2 may be a possible alternative to fungicides in managing tomato fruit post-harvest diseases.