Litchi fruits spoil rapidly after harvest, typically deteriorating within a few days due to fungal infection and browning. Conventional chemical preservatives used to extend shelf life, however, raise food safety concerns. Now, a team led by Prof. Yong‑Xin Liu at the Chinese Academy of Agricultural Sciences has taken a microbiome‑based strategy to offer a new perspective on this challenge.
The researchers tracked bacterial communities on the peel of two litchi varieties – the storage‑tolerant ‘Huaizhi’ and the sensitive ‘Nuomici’ – over nine days under natural and fungicide‑treated conditions. Using amplicon sequencing, time-series analysis, and a random forest model, they found that several bacterial genera, including Methylobacterium , Sphingomonas , and Gluconobacter , showed strong temporal patterns. A random forest model based on microbial biomarkers accurately predicted fruit freshness ( R² >0.90), demonstrating that these peel microbiome can act as a “freshness clock.”
Importantly, the team isolated 80 culturable strains from the peel. One of them, Gluconobacter sp. Lc45, inhibited the growth of the two major postharvest pathogens – Peronophythora litchii (downy blight) and Colletotrichum gloeosporioides (anthracnose) – by more than 63% in vitro and significantly suppressed disease in living fruits. This strain acts through nutrient competition and secretion of antimicrobial metabolites, offering a safe, sustainable alternative to synthetic fungicides.
The study also revealed that storage time, rather than cultivar or fungicide treatment, is the primary driver of microbial succession on the fruit surface. As decay progresses, the community shifts from plant‑beneficial bacteria to decomposer species. This ecological insight helps explain why certain bacterial groups change from a positive to a negative correlation with freshness.
By combining high‑throughput sequencing, culturomics and machine learning, the work provides both a predictive tool for postharvest management and a candidate biocontrol agent. The authors have filed a patent (No. 202610311174.2) based on the results.
Science China Life Sciences
Experimental study