巴丹吉林沙漠盐湖微生物多样性

Microbial diversity of salt lakes in Badain Jaran desert

【目的】研究内蒙古巴丹吉林沙漠碱性盐湖中的原核生物多样性及其与环境因子之间的关系。【方法】利用分子生物学方法构建16S rRNA基因克隆文库,对盐湖中的嗜盐碱微生物进行系统发育分析;利用R语言绘图,对不同盐湖的微生物群落结构进行对比研究。【结果】该区域盐湖含盐量很高,矿化度达165g/L-397 g/L。同时,水体呈强碱性,p H均在10以上。三个湖的盐度和p H值等理化参数有梯度变化,因此微生物多样性和群落结构存在明显差异。整体而言,细菌的多样性大于古菌。样品中含有的主要的细菌门类为γ-变形菌亚门(Gammaproteobacteria)、拟杆菌门(Bacteroidetes)、α-变形菌亚门(Alphaproteobacteria)、厚壁菌门(Firmicutes)、疣微菌门(Verrucomicrobia),古菌则全部属于广古菌门(Euryarchaeota)中的盐杆菌科(Halobacteriaceae)。【结论】盐度是决定细菌群落结构的主要因素,古菌群落结构则由多种环境因素综合影响。一些已知的嗜盐碱菌,如Roseinatronobacter spp.、Halohasta spp.等,可以生活在比其盐度和碱度生长范围更高的极端盐碱环境中。此外,样品中还含有大量未培养的嗜盐碱细菌和古菌,对进一步开发极端盐碱环境中的微生物资源有重要意义。

[Objective] We characterized procaryotic biodiversity,community structure and the relationship between the community structure and environmental factors of salt lakes in Badain Jaran desert,Inner Mongolia,China. [Methods]We constructed 16 S rRNA gene clone libraries by molecular biology techniques to analyze the procaryotic phylogenetic relationships,and used R language to compare the community structure of haloalkalophiles in the salt lakes. [Results]Water in this region has a high salinity ranging from 165 to 397 g / L. The water is strongly alkaline with p H value above10. The microbial diversity and community structure of the salt lakes are obviously different. The diversity of bacteria is more abundant than that of archaea. The main categories of bacteria in the samples are Gammaproteobacteria,Bacteroidetes,Alphaproteobacteria,Firmicute and Verrucomicrobia,whereas all archaea only belong to Halobacteriaceae of Euryarchaeota. [Conclusion] Salinity is the most important environmental factor influencing the bacterial community structure,whereas the archaea community structure was influenced comprehensively by multiple environmental factors.