辽宁盘锦三角洲翅碱蓬根系及内生细菌群落多样性

Diversity of endophytic and rhizospheric bacteria of Suaeda heteroptera Kitag from Panjin Delta in Liaoning Province

摘要:

【目的】翅碱蓬(Suaeda heteroptera)是一种典型的盐碱指示物，对重金属和石油污染的盐碱土壤有一定的修复作用，但是关于翅碱蓬根系与根系内生微生物之间的关系、微生物的多样性以及根系微生物在生物修复中所起作用的研究较少。本文以盘锦“红海滩”的翅碱蓬为例，研究翅碱蓬根系及根系内生细菌菌群种类和结构。【方法】通过传统的培养方法和非培养的高通量测序方法对翅碱蓬根系土壤样品、根系附着物样品以及根系匀浆样品中微生物群落多样性进行分析。【结果】传统方法共分离得到67株细菌，选择代表菌28株，根据其形态特征和生理生化特征，结合16S rRNA基因序列比对进行鉴定，它们分别属于盐单胞菌属(Halomonas)、海细菌属(Marinobacterium)、芽孢杆菌属(Bacillus)、副球菌属(Paracoccus)、假单胞菌属(Pseudomonas)、游动球菌属(Planococlus)、沙雷氏菌属(Serratia)、刘志恒菌属(Zhihengliuella)等。利用高通量测序技术对样品进行多样性分析，其中根系附着物样品的菌群丰度和多样性最高，依次分别为根系土壤样品和根系匀浆样品。3个样品中有效序列群落结构可分为12个门，包括酸杆菌门(Acidobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、绿菌门(Chlorobi)、绿弯菌门(Chloroflexi)、蓝菌门(Cyanobacteria)、厚壁菌门(Firmicutes) 、芽单胞菌门(Gemmatimonadetes)、浮霉菌门(Planctomycetes)、变形菌门(Proteobacteria)、螺旋体门(Spirochaetes)和疣微菌门(Verrucomicrobia)。根系匀浆样品中蓝菌门为优势门类，占整个菌群的42%，变形菌门为次优势类群，占33%。变形菌门在根系附着物样品中为优势门类，占46%，拟杆菌门为次优势门类，占16%。根系土壤样品中拟杆菌门为优势门类，占整个菌群的37%，次优势类群为变形菌门，占20%。【结论】翅碱蓬根系和内生菌具有丰富的多样性，其根系微生物可能会在重金属和石油污染土壤的生物修复中起一定的修复作用。

Abstract:

[Objective] Suaeda heteroptera Kitag which is a typical saline indicator plant has the function of restoring the saline-alkali soil polluted by heavy metals and oil. But little was known about the relationship between its root and endophytic microorganisms, microbial diversity and the function of rhizospheric microorganisms in bioremediation. In this study, we determined the diversity and structure of the endophytic and rhizospheric bacteria of Suaeda heteroptera Kitag from delta area in Panjin Liaoning Province. [Methods] The bacterial diversity in rhizosphere soil, root homogenate and root attachments of Suaeda heteroptera Kitag was analyzed by traditional culture methods and high-throughput sequencing. The selected strains were identified by morphological observation and analysis of 16S rRNA gene sequences and physio-biochemical characteristics. [Results] Sixty-seven strains were isolated from these three samples with traditonal methods, and twenty-eight strains among them were selected as the representative strains. The results showed that the strains were mainly affiliated with the genus Halomonas, Marinobacterium, Bacillus, Paracoccus, Pseudomonas, Planococlus, Serratia and Zhihengliuella. High-throughput sequencing analysis showed that these three samples with highest bacterial diversity were, in order, root attachments, rhizosphere soil and root homogenate. In total, twelve phyla were identified from these samples, which were Acidobacteria, Actinobacteria, Bacteroidetes, Chlorobi, Chloroflexi, Cyanobacteria, Firmicutes, Gemmatimonadetes, Planctomycetes, Proteobacteria, Spirochaetes and Verrucomicrobia. Bacteria assemblage was dominated by Cyanobacteria (42%) and Proteobacteria (33%) in root homogenate. Proteobacteria (46%) and Bacteroidetes (16%) were the predominant phyla in root attachments. Bacteroidetes (37%) and Proteobacteria (20%) were the predominant phyla in rhizosphere soil. [Conclusion] The diversity of endophytic and rhizospheric bacteria of Suaeda Heteroptera Kitag is high, which suggests that the bateria in this environment may play a role in the bioremediation of saline-alkali soil polluted by heavy metals and oil.