湖光岩玛珥湖可培养浮游细菌的BOX-PCR图谱及生物多样性分析

BOX-PCR profiling and biodiversity analysis of cultured bacteria in Huguangyan maar lake

摘要:

玛珥湖是一类具有独特地质构造特征的火山口湖泊, 目前国内外对玛珥湖内微生物多样性的研究还鲜有报道。为了解具有典型玛珥特征的湖光岩湖泊中可培养浮游细菌的种群资源特征, 采用盒式PCR (BOX-PCR) 筛选技术, 通过通用贫营养和原位湖水培养基研究在冬夏两季各水层内获得的可培养细菌种群的差异。结果表明: 不同培养基在不同水层上表现的细菌数量的变化相一致, 为夏季的5 m>1 m>13 m, 冬季的1 m>5 m>13 m, 变形菌占据优势地位, 其它为放线菌、厚壁菌和拟杆菌; 两类培养基上所获培养菌BOX-PCR图谱的多样性相似, 但菌群结构不同; 而细菌多样性在季节上的变化表现为冬季高于夏季, 这与相关湖泊内细菌微生物多样性在夏季会发生减少的特点相似; 相同季节同一水层上不同培养基上获得的培养菌门类不同, 表明此类通用性培养基在培养该环境微生物中的局限。研究的结果为探讨此类型湖泊微生物多样性与环境的关系及分离该环境下特定微生物菌株提供参考。

Abstract:

Maar Lake is a unique type of lake in geological structures, and little is known about microbial diversity in various Maar Lakes worldwide. In order to understand the community structures of culturable bacteria in Huguangyan Lake, a typical Maar lake in South China, BOX-PCR was introduced as a screening technique for bacterial isolates that were obtained from three water depths in winter and summer through the general R2A plates and in situ lake-water agar medium. The results indicated that the changes of bacterial abundance were consistent along water column and on the two types of medium: 5 m>1 m>13 m for summer and 1 m>5 m>13 m for winter, with Proteobacteria as the dominant bacteria followed by Actinobacteria, Firmicutes, and Bacteroides. BOX-PCR profiles for cultured bacteria on both mediums were similar, but their community structures were not identical. The bacterial diversity was higher in winter than that in summer, in consistent with the trends found in other similar primitive lakes. Our results show that using different media may have different limitations in cultivating microbes from natural environments. This study may contribute to the understanding of significant relationship between microbial diversity and environmental characteristics in unique Maar Lakes and to the isolation of novel functional bacteria.