超积累和非超积累生态型东南景天茎、叶内生细菌多样性分析

Characterization of endophytic bacterial communities from leaves and stems of two ecotype of Sedum alfredii by high-throughput sequencing

摘要:

【目的】探究和比较超积累和非超积累生态型东南景天茎、叶微生物群落结构的异同。【方法】采用高通量测序技术研究野外两种生态型东南景天茎和叶片的内生细菌群落结构。【结果】4个样品总共得到366 783条有效序列和39 948个OTU (97%相似度)。从Shannon指数得知：两种生态型东南景天叶片内生菌的多样性均高于茎；超积累生态型东南景天叶片内生菌的多样性高于非超积累生态型，但非超积累生态型东南景天茎组织中内生菌多样性高于超积累生态型东南景天。超积累生态型东南景天的叶片和茎中的内生菌分别包括26和21个门，123和117个科；非超积累生态型东南景天叶片和茎中的内生菌分别包括43和22个门，175和83个科，4个样品的优势菌群均为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)和蓝藻细菌门(Cyanobacteria)。在属分类水平上，超累积生态型东南景天叶片和茎第一优势菌属分别为Synechococcus和Plesiomonas；非超积累生态型东南景天叶片和茎组织第一优势菌群分别为Pseudomonas和Dechloromonas。【结论】两种生态型东南景天的叶片和茎中均具有丰富的内生细菌，但超积累生态型东南景天叶片内生菌多样性最大，且存在一些独有的功能菌群。

Abstract:

[Objective] The ability of accumulation of Zn and Cd between the hyperaccumlating and non-hyperaccumulating ecotypes of Sedum alfredii differed significantly, which might be related to their endophytic bacteria communities. Thus, the objective of this study is to investigate and compare the endophytic bacterial communities between two ecotypes of S. alfredii. [Methods] By using high-throughput sequencing technique, a research on the diversity of endophytic bacterial communities in leaves and stems samples of the hyperaccumulating and non-hyperaccumulating of S. alfredii was conducted. The samples of the hyperaccumulating of S. alfredii were collected from an old lead-zinc mine located in Quzhou city, the west of Zhejiang province, and the non-hyperaccumulating of S. alfredii were collected from a tea garden located in Jiuxi, Hangzhou city, the north of Zhejiang province. [Results] A total of 366 783 sequences and 39 948 operational taxonomic units (OTUs) were obtained from the four samples (at the level of 97%). The index of Shannon indicated that endophytic bacterial biodiversity in the leaves of two ecotype of S. alfredii were consistenly higher than in the stems, endophytic bacterial biodiversity in the leaves of hyperaccumulator ecotype of S. alfredii were higher than in the leaves of non-hyperaccumulator ecotype of S. alfredii, while the reverse was true for the stem samples. Endophytes in the leaves and stems samples of the hyperaccumulator ecotype of S. alfredii included 26 and 21 phyla, 123 and 117 families respectively, while the non-hyperaccumulator ecotype of S. alfredii included 43 and 22 phyla, 175 and 83 families respectively. In addition, the most abundance associated with the four sample libraries were consistently found to be related to Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Cyanobacteria. On the genus level, the most abundance bacteria associated with the leaves and stems of hyperaccumulator ecotype of S. alfredii were Synechococcus and Plesiomonas, while Pseudomonas and Dechloromonas were for the leaves and stems of non-hyperaccumulator ecotype of S. alfredii. [Conclusion] Diverse communities endophytes inhabit leave and stems of the two ecotype of S. alfredii, while the most endophytes diversity of the four samples was the leave of hyperaccumulator ecotype of S. alfredii.