烟叶陈化过程细菌群落演替特征

仓储生态因子和烟叶化学成分的改变直接影响烟叶微生物群落结构和功能。以储存在贵阳库(GY)、坛厂库(TC)及紫云库(ZY)的云南保山C3F烟叶为研究对象,对不同陈化时间(0、6、12、18、24个月)的烟叶样品提取微生物总DNA,利用Illumina Hi Seq平台对细菌的16S rRNA V4区进行高通量测序,并结合主要化学成分分析,以期揭示烟叶陈化过程中细菌群落演替规律及其与烟叶化学成分间的作用关系。研究结果表明,烟叶细菌群落以假单胞菌属、鞘氨醇单胞菌属、寡养单胞菌属、芽孢杆菌属为优势属;随陈化时间的增加,细菌优势群落呈现出变形菌门和厚壁菌门间消长变化的趋势,陈化后期芽孢杆菌(厚壁菌门)优势度明显增强;烟叶陈化过程中,细菌优势功能群变化与化学成分逐级降解间呈显著的相关关系,主要表现为由降解糖类菌群向降解淀粉类菌群,再向降解纤维素类菌群变化的趋势;其中,影响菌群演替的关键因素是水溶性总糖和纤维素。研究结果揭示了在烟叶陈化过程中存在显著的细菌群落演替特征,加深了对烟叶陈化机制的理解,为微生物调控烟叶陈化过程提供了科学依据。

Study on the characteristics of bacterial community succession in tobacco aging

In this study, we investigated the relationship between the community succession and chemical composition of the bacteria isolated from tobacco. The tobacco sample C3F (2013) obtained from Baoshan City, Yunnan Province, was stored in Guiyang (GY), Tanchang (TC), and Ziyun (ZY) storerooms. The 16S rRNA genes of the bacteria isolated from the samples aged 0, 6, 12, 18, and 24 months were sequenced using the Illumina HiSeq2500 high-throughput sequencing platform. The results showed that the Pseudomonas, Sphingomonas, Stenotrophomonas, and Bacillus genera were dominant in the bacterial community. With an increase in aging time, a growth-decline trend was observed between Proteobacteria and Firmicutes in the dominant bacterial communities, and the genus Bacillus was significantly dominant in the later successional stage. In the process of tobacco aging, a significant correlation was found between the dominant functional groups of bacteria and the progressive decomposition of their chemical components. The dynamics of the dominant functional groups of bacteria changed from carbohydrate-like to starch-like and then to cellulose-like. The water-soluble sugar and cellulose were the key factors involved in succession. This study revealed a significant characteristic of the bacterial community succession during aging in tobacco, thereby elucidating the mechanism of tobacco aging and providing a scientific basis for using microbes to control tobacco aging.