云南不同产区醇化烟叶微生物群落特征及其与化学成分的关联性分析

Characteristics of microbial communities in aged tobacco leaves from diverse production areas in Yunnan and their correlations with chemical components

摘要:

目的 探究云南不同产区醇化烟叶的微生物群落特征及其与化学成分的关系，为烟草微生物资源的定向挖掘与烟草品质改良提供理论依据和支持。方法 综合运用宏基因组学、气相色谱/液相色谱-质谱联用技术及斯皮尔曼相关性分析等方法，系统分析大理、文山、红河、罗平、普洱、昭通和临沧共7个云南产区醇化烟叶的微生物群落、化学成分以及两者间的相关性。结果 在各产区醇化烟叶中，细菌以假单胞菌门(Pseudomonadota)为优势菌门，优势细菌属呈现明显的地域差异。其中，文山产区以盐水弧菌属(Salinivibrio)为核心菌属，罗平产区以甲基杆菌属(Methylobacterium)和鞘氨醇单胞菌属(Sphingomonas)为典型代表；真菌以子囊菌门(Ascomycota)和毛霉门(Mucoromycota)为主，优势真菌属无地域差异。临沧产区的微生物丰富度和多样性最高，文山产区最低。KEGG注释显示，新陈代谢通路在各产区均具有较高丰度，环境信息处理通路则在文山产区呈现较高丰度。CAZy结果显示，被注释的糖苷水解酶(glycoside hydrolases, GHs)和糖基转移酶(glycosyl transferases, GTs)基因数目最多，且二者在文山产区的丰度较低。化学分析结果显示，大理产区烟叶的还原糖、总糖等常规成分含量较高，普洱产区的糖碱比和钾氯比均较高；文山产区含有较高含量的苯甲醇等多种中性致香成分，罗平产区则含有较高含量的花青素等多酚物质。相关性分析表明，微杆菌属(Microbacterium)与总氮呈显著正相关，短柄霉属(Aureobasidium)与总氮呈显著负相关；白冬孢酵母属(Leucosporidium)与钾离子和钾氯比呈显著正相关；盐水弧菌属(Salinivibrio)与多种中性致香成分呈显著正相关，甲基杆菌属(Methylobacterium)和弗莱德门氏菌属(Friedmanniomyces)则与多数中性致香成分呈显著负相关；甲基杆菌属(Methylobacterium)、鞘氨醇单胞菌属(Sphingomonas)、弗莱德门氏菌属(Friedmanniomyces)和梅奇酵母属(Metschnikowia)与大部分多酚物质呈显著正相关。结论 云南不同产区醇化烟叶的微生物群落及化学成分均存在显著的地域差异，且醇化烟叶中的优势菌属与香气化合物存在显著关联，这为功能微生物的定向筛选和烟叶提质生物技术开发提供了理论支撑。

Abstract:

Objective This study examined the characteristics of the microbial communities and their associations with chemical components in aged tobacco leaves from different production areas in Yunnan Province, aiming to provide a theoretical foundation for the targeted exploitation of tobacco microbial resources and quality improvement of tobacco.Methods A systematic approach integrating metagenomic sequencing, GC/LC-MS, and Spearman’s correlation analysis was employed to investigate the microbial communities, chemical components, and their correlations of aged tobacco leaf samples collected from Dali, Wenshan, Honghe, Luoping, Pu’er, Zhaotong, and Lincang.Results The dominant bacterial phylum was Pseudomonadota in aged tobacco leaf samples. The dominant bacterial genera varied among different production areas. Specifically, Salinivibrio was identified as the core genus in the samples from Wenshan, while Methylobacterium and Sphingomonas exhibited significant enrichment in the samples from Luoping. For fungal communities, Ascomycota and Mucoromycota were the predominant phyla, and dominant fungal genera showed negligible variations. Alpha diversity analysis revealed the highest microbial richness and diversity in the samples from Lincang and the lowest in the samples from Wenshan. KEGG analysis revealed that metabolic pathways exhibited high relative abundance across samples from all regions, whereas environmental information processing pathways were more abundant in the samples from Wenshan. CAZy analysis showed that genes annotated as glycoside hydrolases (GHs) and glycosyl transferases (GTs) were the most prevalent, with both generally exhibiting lower abundance in the samples from Wenshan. Chemical profiling revealed that reducing sugar, total sugar and other conventional components were more concentrated in the samples from Dali, whereas total sugar-to-nicotine ratio and potassium-to-chloride ratio were elevated in the samples from Pu’er. Additionally, neutral aroma compounds, including benzyl alcohol, had significantly higher levels in the samples from Wenshan, while polyphenols such as anthocyanins exhibited markedly higher concentrations in the samples from Luoping. Correlation analysis further disclosed that Microbacterium had a significantly positive correlation with total nitrogen, while Aureobasidium showed a significantly negative correlation with total nitrogen. Leucosporidium exhibited significantly positive correlations with potassium ions and potassium-to-chloride ratio. Salinivibrio had significantly positive correlations with multiple neutral aroma components. In contrast, Methylobacterium and Friedmanniomyces showed significantly negative correlations with the majority of neutral aroma components. Additionally, Methylobacterium, Sphingomonas, Friedmanniomyces, and Metschnikowia had significantly positive correlations with multiple polyphenols.Conclusion Microbial communities and chemical components of aged tobacco leaves exhibited marked differences across different production areas in Yunnan. Notably, dominant genera are strongly correlated with aroma compounds, which lays a theoretical basis for targeted screening of functional microbes and the development of biotechnologies to improve tobacco quality.