Biocontrol efficacy and possible mechanism of a broad-spectrum antagonistic yeast, Pichia kluyveri NY23, screened from peach fruit via microbiome analysis

Abstract

Fungus-induced postharvest diseases are the leading causes of fruit loss and waste. Meanwhile, some pathogens also produce mycotoxins, posing a grave risk to public health. Fruit epicarps harbor abundant microbiota, and shifts in these communities are tightly coupled with the occurrence of postharvest disease. Microbiomics research thus offers a new framework not only for understanding the pathogenesis of fruit decay but also for devising innovative biocontrol strategies. In this study, the microbial community composition and diversity across three harvested peach varieties were investigated. Variations in epiphytic microbiota on peach fruit across distinct cultivars and storage times were assessed. A core taxon recovered from all fruit samples, which displays broad-spectrum antifungal activity, was isolated, identified, and designated as Pichia kluyveri NY23. Volatile organic compounds (VOCs) produced by P. kluyveri NY23 can reduce the pathogen’s pathogenicity and mycotoxin synthesis by inhibiting spore germination and downregulating mycotoxin biosynthetic gene expression. The maximum inhibitory efficacy of the VOCs against pathogen spore germination and mycotoxin biosynthesis reached 100% and 99.1%, respectively. GC-MS profiling revealed eight VOCs, among which phenethyl acetate, isoamyl acetate, ethyl acetate, and phenethyl alcohol are major components. Individually, the VOCs exhibited strong antifungal properties and can markedly suppress mycotoxin production. These findings highlight the potential of P. kluyveri NY23 and its major VOCs as effective biocontrol agents against postharvest diseases on different fruit.