新疆红井子盐碱土壤非培养放线菌多样性

Actinobacterial diversity of a soil sample from Hongjingzi in Xinjiang by using culture-independent method

摘要:

【目的】研究新疆红井子盐碱土壤中的放线菌物种多样性。【方法】应用基于16S rRNA基因序列系统发育分析的免培养方法进行放线菌物种多样性分析。利用放线菌特异性引物, 以土壤样品总DNA为模板, 扩增16S rRNA基因, 构建16S rRNA基因克隆文库, 并对文库中的插入序列进行RFLP分析。【结果】随机挑选的246个阳性克隆通过酶切筛选出61个不同图谱的重组克隆并测序。分析结果显示这61 个克隆序列分属于42 个OTUs, 分布于放线菌纲(Actinobacteria)的放线菌亚纲(Actinobacteridae)、酸微菌亚纲(Acidimicrobidae)和红色杆菌亚纲(Rubrobacteridae); 该环境中有71.4%的序列与已有效发表菌株的序列相似性小于97%, 代表着放线菌新类群, 其中部分序列形成了几个独立的进化分支, 可能代表更高级的新分类单元。【结论】红井子土壤中的放线菌组成具有丰富的多样性, 并有新放线菌分类单位的潜在资源, 值得进一步进行开发研究。

Abstract:

[Objective] The aim of this study was to investigate the actinobacteria diversity of the saline-alkali soil from Hongjingzi located in XinJiang Province. [Methods] The diversity of actinobacteria in this soil was investigated by using culture-independent method based on phylogenetic analysis of 16S rRNA gene sequences. The specific primers for the class Actinobacteria were used to amplify the partial 16S rRNA gene, and then clone library for the soil sample was constructed. A total of 246 positive clones chosen randomly from the clone library were digested with Hae III for RFLP analysis. [Results] Among of them, 61 different clones selected were sequenced. The analysis of 16S rRNA gene sequences showed that the clone sequences went back to 42 OTUs and belonged to subclasses Actinobacteridae, Acidimicrobidae and Rubrobacteridae respectively. The 71.4% of the detected sequences from this soil was less than 97% similarity to the published sequences, which might represent new taxa. Some sequences, which formed several distinct clades in phylogenetic tree may represent new taxonomical groups of actinobacteria. [Conclusion] These results indicate that the soil from Hongjingzi region be abundant actinobacteria, including large number of unknown actinobacterial taxa, which would be further explored.