A novel volatile organic compound composite from Wickerhamomyces anomalus controls blue and gray mold of kiwifruit through direct inhibition and host resistance activation

Abstract

Postharvest blue and gray mold diseases are major threats to kiwifruit storage, causing significant economic losses worldwide. This study developed a potent biocontrol agent by formulating a composite of eight volatile organic compounds (VOCs) produced by Wickerhamomyces anomalus. These VOCs mainly consist of esters and alcohols, with 2-Phenethyl acetate and 3-Methyl-1-butanol being the most abundant components. The VOC composite exhibited complete fungal inhibition (100 %), significantly outperforming individual VOCs, which achieved inhibition rates below 40 %. Fumigation with the VOC composite effectively controlled blue and gray mold diseases, preventing lesions at a dose of 50 units, and reducing the decay rate to 26.67 % by day 21, compared to 86.67 % in the control group. The antifungal activity was associated with inhibiting spore germination and mycelial growth, structural deformation and collapse of fungal cells, and disruption of cell membrane integrity. Furthermore, the VOC composite enhanced antioxidant enzyme activities and promoted the accumulation of disease-resistant metabolites, such as total phenols and flavonoids, boosting systemic resistance in kiwifruit. These findings highlight the potential of microbial VOCs as sustainable and eco-friendly biocontrol agents for managing postharvest diseases in kiwifruit.