不同品质烟叶微生物群落与其挥发性成分的关联研究

Study on the Correlation Between Microbial Communities and Volatile Aroma Compounds in Tobacco Leaves of Different Qualities

为揭示烟叶表面优势微生物群落与其品质的关系,采用高通量技术分析了不同品质烟叶的微生物群落结构,使用固相微萃取与气相色谱-质谱联用技术检测其挥发性香气物质,通过计算Pearson相关系数分析与烟叶挥发性香气成分形成相关的优势微生物种属。结果显示,烟叶中优势细菌为贪噬菌属(Variovorax)、鞘氨醇单胞菌属(Spingomonas)、芽孢杆菌属(Bacillus),优势真菌为桑帕约氏酵母(Sampaiozyma)、曲霉(Aspergillus)、枝孢霉属(Cladosporium)。细菌群落与烟叶品质差异相关,贪噬菌属(Variovorax)、鞘氨醇单胞菌属(Spingomonas)、红球菌属(Rhodococcus)等的相对丰度在上等烟、中等烟中上调;而真菌群落与烟叶的地域差异相关。在中、上等烟中含有较高呈焦糖香的糠醛和5-羟甲基糠醛,呈甜奶香的香兰素等挥发性成分;下等烟中则含有更多α-尼古丁,增加烟气刺激性。结合相关性分析,发现细菌物种与烟叶中多种挥发性香气物质呈正相关,红球菌属(Rhodococcus)、贪噬菌属(Variovorax)和芽孢杆菌属(Bacillus)是烟叶中主要的风味关联菌。结果表明烟叶中优势菌群在促进其香气品质形成中发挥着重要作用,这为实现以微生物技术对烟叶提质减害、风味定向调控提供了理论参考。

To reveal the relationship between the dominant microbial communities on tobacco leaf surface and the quality of tobacco, the structure of microbial community in tobacco with different qualities was analyzed by high-throughput sequencing technique, and the volatile aroma compounds were detected by solid-phase microextraction coupled with gas chromatography-mass spectrometry(SPME-GC/MS), and the dominant microbial species related to the formation of volatile aroma components in tobacco were analyzed by calculating Pearson correlation coefficient. The results showed that the dominant bacteria in tobacco were Variovorax, Spingomonas, and Bacillus, while the dominant fungi were Sampaiozyma, Aspergillus, and Cladosporium. The bacterial communities were related to the difference of tobacco leaf qualities, and the relative abundance of Variovorax,Spingomonas, and Rhodococcus was up-regulated in the high-grade and middle-grade tobacco leaves.However, the fungal communities were related to the geographic location differences of tobacco leaves. The contents of volatile compounds were higher in high-grade and middle-grade tobacco,such as furfural and 5-methyl-2-furancarboxaldehyde of caramel aroma, and sweet milk-flavored vanillin. There was more α-nicotine producing irritating smoke in the low-grade tobacco. Combined with the correlation analysis, a positive correlation was found between bacterial species and various volatile aroma compounds in tobacco leaves, and Rhodococcus, Variovorax and Bacillus were the main flavor-associated bacteria in tobacco. The results showed that the dominant microbiota in tobacco played a critical role in promoting the formation of tobacco aromatic quality, which could provide a theoretical reference for the realization of tobacco quality improvement and damage reduction, as well as the targeted regulation of flavor based on the microbial technology.