Antifungal activity of Hanseniaspora uvarum VOCs against Alternaria alternata and Botrytis cinerea in blueberry by disrupting growth metabolism.

This study evaluated the biocontrol effects of volatile organic compounds (VOCs) derived from the epiphytic yeast Hanseniaspora uvarum against Botrytis cinerea and Alternaria alternata in blueberry fruits and investigated the associated mechanisms. According to the results, VOCs remarkably suppressed mycelial growth, sporulation, and spore germination, causing severe morphological abnormalities, including twisted and fragmented hyphae, in vitro. In vivo fumigation of blueberry fruits effectively reduced disease incidence and lesion diameter. Physiological assays indicated that VOCs disrupted cell membrane integrity, which was verified by decreased ergosterol content, enhanced extracellular conductivity, and leakage of intracellular nucleotides, proteins, and sugars. VOCs also induced reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) elevation, indicating lipid peroxidation and oxidative stress. Transcriptomic analysis revealed distinct pathogen-adapted responses: in A. alternata, VOCs suppressed genes involved in redox homeostasis, membrane biosynthesis, and transport while up-regulating catabolic pathways; in B. cinerea, VOCs down-regulated core transcriptional and translational mechanisms and triggered compensatory up-regulation of alternative RNA polymerases, cell cycle checkpoints, and detoxification genes. These results suggest that VOCs produced by H. uvarum exert broad-spectrum antifungal effects by interfering with pathogen growth and metabolism through multiple targets. Our findings demonstrate that H. uvarum VOCs act as a contact-free and eco-friendly biofumigant to control postharvest decay in blueberries and lay the molecular foundation for their application in fruit preservation.