新疆巴里坤、七角井和台特玛盐湖沉积物中免培养放线菌群落组成与离子成分分析

Actinobacterial community and ionic composition in sediment of Xinjiang saline lakes: Barkol, Qijiaojing and Taitema

【背景】新型病原微生物层出不穷,放线菌作为最重要的抗生素生产菌仍受制于纯培养困难和菌种资源不足,而对于盐湖沉积物中的丰富放线菌资源却鲜有报道。【目的】探索巴里坤、七角井和台特玛盐湖沉积物放线菌群落结构及其多样性,分析盐湖沉积物中化学离子成分对放线菌群落的影响。【方法】每个盐湖采集5份样品并混合,使用SDS-CTAB抽提法提取总DNA,使用放线菌特异性引物进行PCR扩增并构建16S r RNA基因文库,每个样品随机挑选220个克隆子,经过Hae III酶切筛选后对阳性克隆子进行测序分析;对每个样品的8种主要化学离子进行检测,并将沉积物化学离子成分与放线菌群落进行关联性分析。【结果】获得的381个克隆序列属于143个操作分类单元(Operational taxonomic Unit,OTU),聚类结果显示从3个盐湖中共探测到37个放线菌属(台特玛盐湖:24;巴里坤盐湖:16;七角井盐湖:14)。3个盐湖共有的放线菌属为Aciditerrimonas、Aquihabitans、Demequina、Dietzia、Ilumatobacter和Amycolatopsis。从放线菌群落结构上看,台特玛盐湖与其他两湖差异性很大,巴里坤盐湖与七角井盐湖群落相似性更高,巴里坤、七角井和台特玛盐湖未知放线菌的组成分别为47.59%、53.07%和51.53%。利用RDA(Redundancy analysis)分析盐湖沉积物化学离子与放线菌群落的关联性,结果显示与Na^+、Cl^-和K^+相比,Mg^(2+)、Ca^(2+)、SO_4^(2-)、HCO_3^-和CO_3^(2-)与盐湖放线菌类群的相关关系要更加紧密。【结论】3个盐湖中具有丰富的放线菌多样性,包含大量的未知放线菌。盐湖沉积物不同的化学离子成分影响着各自独特的放线菌群落,可为开发新的盐湖放线菌资源提供依据。

[Background] New pathogenic microorganisms are constantly emerging, Actinobacteriaare the most important antibiotic-producing bacteria which are hampered by the shortage of efficient strains and the difficulty of pure cultivation, but there are few reports of the abundant Actinobacteriain the sediment of saline lake. [Objective] The aim of this study was to investigate actinobacterial diversity in the sediment of Xinjiang saline lakes： Taitema, Barkol and Qijiaojing, and the relationship between the actinobacterial community and ionic composition. [Methods] From every lake we collected 5 samples and mixed, to extract total DNA by using SDS-CTAB. We used primers for the class Actinobacteria for actinobacterial l6 S r RNA gene amplification and then constructed a clone library for the sediment sample. In total 220 clones were randomly selected from each sample, from which the positive clones were screened on the basis of Hae III digestion patterns, and then these positive clones were sequenced. Eight major chemical ions were detected in each sample, and then the correlation between chemical ions and actinobacterial community was analyzed. [Results] In total 143 Operational Taxonomic Units（OTUs） were obtained from 381 clones which belonged to 37 actinobacterial genera（Taitema： 24, Barko： 16, Qijiaojing： 14）. The common Actinobacteria of the three lakes were Aciditerrimonas, Aquihabitans, Demequina, Dietzia, Ilumatobacter andAmycolatopsis. Barkol was closer to Qijiaojing at the actinobacterial community composition, but Taitema had huge difference from the other two. There were plenty of unknown Actinobacteria in the Sediment of these Lakes, it reached 47.59% in the whole Actinobacteria at Barkol, 53.07% at Qijiaojing and 51.53% at Taitema. Redundancy analysis was used to analyze the relationship between chemical ions and actinobacterial community, and the results showed that Mg^2＋, Ca^2＋, SO4^2-, HCO3^- and CO3^2- had closer ties with the actinobacterial community than Na^＋, Cl^- and K^＋. [Conclusion] These lakes contained plenty of unknown Actinobacteria which were worth to exploring and different ions influenced unique Actinomycetes community.