Metagenomics Insights into the Role of Microbial Communities in Mycotoxin Accumulation During Maize Ripening and Storage

Mycotoxins are among the primary factors compromising food quality and safety. To investigate mycotoxin contamination, microbial diversity, and functional profiles in maize across distinct geographic regions, this study analyzed samples from Xuanwei, Fuyuan, and Zhanyi. Mycotoxin concentrations were quantified through standardized assays, while microbial community structures were characterized using metagenomics sequencing. Metabolic pathways, functional genes, and enzymatic activities were systematically annotated with the KEGG, eggNOG, and CAZy databases. The results demonstrated an absence of detectable aflatoxin (AF) levels. Deoxynivalenol (DON) concentrations varied significantly among experimental cohorts, although all values remained within regulatory thresholds. Zearalenone (ZEN) contamination exceeded permissible limits by 40%. The metagenomic profiling identified 85 phyla, 1219 classes, 277 orders, 590 families, 1171 genera, and 2130 species of microorganisms, including six mycotoxigenic fungal species. The abundance and diversity of microorganisms were similar among different treatment groups. Among 32,333 annotated KEGG pathways, primary metabolic processes predominated (43.99%), while glycoside hydrolases (GH) and glycosyltransferases (GT) constituted 76.67% of the 40,202 carbohydrate-active enzymes. These empirical findings establish a scientific framework for optimizing agronomic practices, harvest scheduling, and post-harvest management in maize cultivation.