雪茄烟发酵过程微生物群落结构及物种均衡性变化特征

Changes of Microbial Community Structure and Species Balance in Fermentation of Cigar Tobacco

为明确雪茄烟叶发酵过程中微生物群落组成、结构及物种均衡性的变化特征,基于高通量测序技术,采用细菌、真菌多样性指数比值分析方法,对不同发酵阶段雪茄烟叶表面细菌、真菌进行分析。结果表明,随发酵进行,细菌α多样性先升高后降低,在PEF3(中期)达到最高值;真菌α多样性基本稳定,仅在发酵PEF4(后期)显著降低;物种均衡性在前中期小幅度升高,但在PEF4后显著降低。PCoA分析显示,未发酵与发酵前中期细菌群落结构相似,与发酵后期明显分离。在发酵过程中,细菌葡萄球菌属(Staphylococcus)、假单胞菌属(Pseudomonas)和真菌明梭孢属(Monographella)、曲霉菌属(Aspergillus)、青霉菌属(Penicillium)为主要优势菌属。影响物种均衡性的关键微生物群落变化规律是:由发酵初期的泛生菌属(Pantoea)、甲基杆菌属(Methylobacterium)、鞘氨醇单胞菌属(Sphingomonas),变为发酵中期马赛菌属(Massilia)、壤霉菌属(Agromyces)、根瘤菌科(Rhizobiaceae),最后稳定为Staphylococcus、Pseudomonas、Trichomonascus、雷尔氏菌属(Ralstonia)、Monographella。将微生物分为两个模块研究,共筛选出8个有利于提高物种均衡性的关键菌属。最终结构方程模型表明,在雪茄烟叶发酵过程中,影响物种均衡性改变的主要环境因子是温度和湿度,二者通过影响关键菌属的丰度而影响物种均衡性。

Aiming for the changes of microbial community composition,structure,and species balance in cigar tobacco fermentation,the surface bacteria and fungi of cigar tobacco at different fermentation stages were analyzed by using high-throughput sequencing technology and ratio analysis method of bacterial and fungal diversity index.Results showed that with the fermentation process,theαdiversity of bacteria increased at first and then decreased,and peaked in PEF3(middle stage).Theαdiversity of fungi was basically stable,yet significantly decreased in PEF4(late stage).The species balance slightly increased in early and middle stages,while significantly decreased after PEF4.PCoA analysis showed that the bacterial community structure of unfermented and pre fermentation exhibited similar,while significantly separated from that of post fermentation.The dominant genera in fermentation were bacterial Staphylococcus,Pseudomonas,and fungal Streptomyces,Aspergillus,Penicillium,respectively.The key microbial community changes affecting species balance are from Pantoea,Methylobacterium,and Sphingomonas of early stage to Massilia,Agromyces,Rhizobiaceae of middle stage,and finally stabilized with Staphylococcus,Pseudomonas,Trichomonas,Ralstonia and Monogramella.Microorganisms were divided into two modules,and a total of 8 key genera beneficial for improving species balance were selected out.The final structural equation model indicates that in fermentation of cigar tobacco,the main environmental factors affecting species balance are temperature and humidity,which affect species balance by affecting the abundance of key bacterial genera.