Fungal community analysis of hot spots in bulk maize under different storage conditions

Maize is one of the main cereals used for food and livestock feed. During storage, maize is easily infected by fungi to form mildew or cause hot spots, resulting in maize quality loss and potential safety hazards. We collected maize samples from normal spots and hot spots in three warehouses with different storage conditions (i.e., normal storage, N2-controlled atmosphere storage, and phosphine fumigation treatment storage) and used high-throughput sequencing and traditional culturing methods to investigate the fungal communities inducing hot spots. The results showed that there were large differences in the fungal communities on the maize within the three storage warehouses, and the community compositions of the hot spots and normal spots were different within the same warehouse. The storage conditions were highly associated with the fungal community alpha and beta diversities. Aspergillus penicillioides, A. vitricola, and A. chevalieri were the dominant fungal species inducing hot spots. Furthermore, the grain temperature and moisture content were significantly correlated with fungal community composition in hot spots and normal spots. These data are useful for grain depot managers evaluating the potential risks of fungi-induced hot spots and for optimizing storage conditions to reduce the risks of hot spots during maize storage.