Hyperin application modulates leaf bacterial communities and reduces tobacco-specific nitrosamines in air-cured Burley tobacco.

To study the effect of hyperin on the bacterial community diversity and richness on the leaves surface of Burley tobacco, a variety of Burley tobacco 'Eyan 1' was used as the research material. The day before the harvest, all leaves in the treatment group were sprayed with hyperin, while all leaves in the control group were treated with pure water. Samples were collected on the day of harvesting, as well as two weeks and four weeks after air-curing. The results showed that the application of hyperin could potentially affect the bacterial community diversity and richness on the Burley tobacco leaves. Bacterial community structure, co-occurrence patterns, and predicted metabolic pathways were analyzed. Hyperin treatment was associated with increased relative abundance of several genera, including Agrobacterium, Stenotrophomonas, and Bacillus, which have been previously linked to nitrogen transformation or TSNA reduction. These microorganisms may contribute to TSNA reduction during air-curing, thereby reducing TSNA accumulation in the upper leaves of Burley tobacco. The results of this study can furnish evidence for investigating the impact of hyperin on the microbial community and deepen our understanding of the regulatory mechanisms of hyperin in Burley tobacco.