中川208烟草内生细菌微生物群落结构及其多样性

Community structure and diversity of endophytic bacteria in tobacco variety Zhongchuan 208

【目的】分析中川208四个器官(根、茎、叶、花)的细菌群落多样性与物种组成,为利用中川208内生细菌资源提供科学依据。【方法】以中川208的根、茎、叶、花为研究对象,采用高通量测序与生物信息学分析方法,解析中川208不同器官内生细菌的群落结构与物种组成,探讨植物养分特征对优势细菌菌群的调控作用。【结果】(1)从中川208四种样品中共获得5460条特征序列(amplicon sequence variants:ASVs),归属于19门、72纲、161目、285科和389属。(2)各样本的细菌群落多样性为根>茎≥花>叶。Beta多样性和聚类分析表明,中川208的根和叶内生细菌群落组成较相似,与花和茎有明显区别。(3)物种组成上,根、茎、叶内以变形菌门和放线菌门相对丰度最高,花中以厚壁菌门和拟杆菌门的相对丰度最高。LEfSe分析结果表明,中川208不同器官中的细菌群落构成在属水平上存在显著差异性,特别是细菌属不动杆菌、短波单胞菌、异根瘤菌、芽孢杆菌、金黄杆菌、肠杆菌、另枝菌、毛螺菌、普拉梭菌、瘤胃球菌和Rosenbergiella的相对丰度在茎、叶、花内差异显著。(4)冗余分析表明,烟株总N(R2=0.730, P <0.001)、总糖(R2=0.883, P <0.001)和Mg(R2=0.907, P <0.01)含量与各器官中的优势细菌群落分布密切相关。【结论】中川208内生细菌群落多样性自根依次向花、茎、叶呈递减趋势,且不同器官中的内生细菌群落在物种组成上具有明显差异性。中川208植物器官中存在多种显著富集的细菌菌群,值得进一步研究与开发利用。

[Objective]Zhongchuan 208 is a novel flue-cured tobacco variety with good quality,economic prospects,and disease and stress resistance,which is predominantly grown in Southwest and central parts of China.This study aims to investigate the bacterial community structure and species diversity constituents in Zhongchuan 208’s four organs:namely,roots and above ground parts(stem,leaf and flower),and establish a basis of tobacco microbiome,in order to provide a knowledge base of exploiting and utilizing endophytic bacterial resources.[Methods]The aforementioned parts of Zhongchuan 208 were used as research materials,and their high-throughput amplicon sequencing of V3-V4 fragment of bacterial 16S rRNA genes was conducted using the Illumina NovaSeq 6000 platform.The bacterial community structure and species diversity of different organs as well as the effects of plant nutrition on bacterial community were examined using bioinformatics.[Results](1)There were 5460 amplicon sequence variants(ASVs)obtained from four samples of Zhongchuan 208,belonging to 19 phyla,72 classes,161 orders,285 families and 389 genera.(2)The bacterial community diversity of different organs could be ranked in the order of root>stem≥flower>leaf.The Beta diversity analysis and clustering analysis indicated a high degree of similarity in the community composition of endophytic bacteria between root and leaf of Zhongchuan 208,but a significant difference was observed in that between flower and stem.(3)Proteobacteria and Actinobacteria were the dominant phyla of endophytic bacterial communities in roots,stems and leaves,while Firmicutes and Bacteroidetes had the highest relative abundance in flowers.LEfSe analysis showed that the bacterial community composition of Zhongchuan 208 was significantly different at the genus level,the bacterial community was mainly characterized by different endophytic bacteria such as Acinetobacter,Brevundimonas,Allorhizobium,Bacillus,Chryseobacterium,Enterobacter,Alistipes,Lachnospira,Faecalibacterium,Ruminococcaceae_UCG_014 and Rosenbergiella in stem,leaf and flower.(4)Redundancy analysis showed that the contents of total N(R2=0.730,P<0.001),total sugar(R2=0.883,P<0.001)and Mg(R2=0.907,P<0.01)in Zhongchuan 208 were strongly associated with the dominant bacterial communities found in these organs.[Conclusion]The bacterial community diversity in Zhongchuan 208 decreased from roots to flowers,stem and/or leaves,and the species composition of endophytic bacterial communities in different organs was significantly different.There are many significantly enriched bacterial flora in plant organs of Zhongchuan 208,which are worthy of further research and exploitation.