Time-series dynamics and biocontrol potential of postharvest bacteria in litchi microbiota

Postharvest surface microbiota plays a pivotal role in fruit spoilage and disease development, directly influencing shelf life and food safety. In this study, we systematically investigated the dynamic changes of peel-associated microbial communities in two litchi cultivars with distinct storability (Huaizhi and Nuomici), under both natural and fungicide (prochloraz) treatments over a 9 d storage period. Amplicon sequencing, time-series analysis, and a random forest model identified five key genera-Acetobacter, Methylobacterium, Sphingomonas, Gluconobacter, and Pantoea-strongly associated with storage time. Notably, culturable isolates from these genera exhibited significant antagonistic activity against the common postharvest fungal pathogens Peronophythora litchii and Colletotrichum gloeosporioides, with Gluconobacter sp. Lc45 demonstrating high-efficiency antagonism. Furthermore, a random forest model based on microbial biomarkers accurately predicted fruit freshness (R²>0.9). This study highlights the ecological and biocontrol significance of surface microbiota on litchi, and proposes microbial-based strategies as promising eco-friendly alternatives for postharvest disease control and freshness prediction in subtropical fruits.