为了揭示沙坡头沙漠固沙区与流沙区不同植物根际微生物群落结构的组成、丰度和多样性对沙漠极端环境的响应，采用DNA提取试剂盒提取土壤总DNA，对细菌群落编码16S rRNA的基因（16S rDNA）的V4～V5区进行MiSeq测序，分析各样品中细菌群落结构的组成、丰度以及多样性指标，通过非度量多维尺度（ NMDS）法和文氏（ Venn）图解释微生物群落结构对环境的响应。固沙区与流沙区不同土壤样品微生物群落在门水平上主要以变形细菌门（Proteobacteria）、放线菌门（Actinobacteria）、酸杆菌门（Acidobacteria）和蓝细菌门（Cyanobacteria）为优势类群。在属水平上，不同样品优势类群差异明显。11个样品在NMDS纵轴方向上按照固沙区与流沙区分为2大组，说明微生物类群对人工固沙做出了环境响应。文氏图分析结果表明，尽管不同样品之间存在一定差异，但存在共有微生物类群，可能在沙坡头沙漠生态系统中发挥着核心作用。蓝细菌以及根瘤菌在沙生植物固沙过程中对于提供营养物质等生物地球化学循环起着重要作用。%Community composition, abundance and diversity of soil microbe in different vegetation rhizospheres and their responses to desert extreme environments in an artificial sand fixed area and a natural bare sand area in the Shapotou Des⁃ert, were studied. In the study, soil total DNA was extracted with the aid of the E.Z.N.A.® Soil DNA Kit, V4-V5 sections of the 16S rDNA of the soil bacterial community analyzed with a MiSeq pyrosequencer for community composition, abun⁃dance and diversity of the soil bacteria, and responses of the soil microbial community in structure to changes in environ⁃ment explained with the NMDS and Venn diagrams. In the soil samples, no matter from which area, Proteobacteria, Acti⁃nobacteria, Acidobacteria and Cyanobacteria were dominant groups in the soil microbial community on the phylum level, while the soil samples from the two different areas differed sharply in dormancy of groups on the genus level. The 11 soil samples were divided into two groups along the vertical axis of the NMDS in accordance with the artificial sand fixed area and the natural bare sand area, indicating that the microbial community responded to changes in the environment, i. e. sand fixation. The Venn diagram analysis indicates that although some differences are found between different soil samples, groups of microbes common in the two groups of soil samples exist and are thought to play a core role in the Shapotou Des⁃ert ecosystem. Cyanobacteria and Rhizobia are the two species of soil microbes that play an important role in biogeochemi⁃cal cycling, like providing nutrients to psammophytes in sand⁃fixing process.
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