关键词: 高通量测序；稻谷；模拟储藏；菌群结构；优势真菌属

Abstract: Objective: To explore the fungal diversity and the change in the fungal community structure in stored rice under different environmental conditions. Methods: The fungal community structure and dominant genera in fresh rice and rice stored at different temperatures (10, 20, 25, 30 and 40 ℃) and relative humidities (43%, 75% and 85%) in Hengyang, Hunan were analyzed by Illumina HiSeq high throughput sequencing. Results: According to the species classification analysis based on operational taxonomic units (OTU), the fungal communities in all samples included 6 phylum, 24 classes, 67 orders, 160 families, 285 genera and 406 species. Ascomycetes was the dominant phylum with a relative abundance of 2.53%–96.86%. followed by Basidiomycetes with a relative abundance of 0.02%–9.39%. The dominant genera included Beauveria, Ophiosphaerella, Aspergillus, Gibberella, Alternaria, Phaeosphaeria, Nigrospora, Microdochium and Candida. The dominant species included B. bassiana, O. agrostidis, A. flavus, A. ochraceus, A. niger, G. intricans, A. longissima, P. microscopica and N. oryzae. Through Venn diagram analysis and principal component analysis (PCA), it was found that there were significant differences in the fungal community diversity between fresh and stored rice samples, and between stored rice samples. There were also differences in the fungal community diversity of rice samples under different temperature and humidity conditions. Conclusion: Relative humidity was the most important factor affecting the relative abundance of A. flavus with the maximum value being observed at 85% relative humidity. To sum up, this study provides theoretical support for the optimization of safe storage conditions for rice.

Key words: high-throughput sequencing; rice; simulated storage; microbial community structure; dominant fungal genera