乌梁素海富营养化湖区浮游细菌多样性及系统发育分析

水生生态系统富营养化与细菌群落之间的关系尚不明确。本文通过构建和分析16S rRNA基因片段克隆文库, 以期揭示乌梁素海富营养化水体细菌的多样性及其系统发育关系, 并探讨富营养化与细菌多样性之间的关系。利用Hae III对文库中的87个克隆子进行单酶切, 产生了23种带型, 文库覆盖度达到了73.6%, 反映出文库有较好的代表性。选择每种OTU的一个代表克隆进行测序分析, 基因序列系统发育分析结果表明, 乌梁素海中多数细菌与淡水生态系统中常见的细菌门类相同, 即α-, β-, γ-Proteobacteria, Bacteroidetes, Actinobacteria, 它们分别占总菌数的10.3%、41.4%、4.6%和6.9%, 其中β-Proteobacteria和Bacteroidetes是优势细菌类群。与典型淡水生态系统细菌群落组成不同的是, 乌梁素海中存在约10.3%的轻度嗜盐碱细菌。水体中83.9%的细菌与已培养的细菌的同源性低于97%, 其中58.9%的细菌未能鉴定到属; 其余总菌数16.1%的克隆与具有降解污染物生物活性的已知菌相近。Bacteroidetes、Firmicutes和β-Proteobacteria中的某些类群成为优势菌群可能是对乌梁素海水体富营养化的响应。

Diversity and phylogenetic analysis of planktonic bacteria in eutrophic zone of Lake Wuliangsuhai

The relationship between the bacterial communities and eutrophication of aquatic ecosystem is not clear. We investigated and analyzed the planktonic bacterial diversity and phylogeny of Wuliangsuhai Lake by using the construction of 16S rRNA gene clone library, and discussed the relationship between the bacterial community and eutrophication. Totally 87 clones were digested with Hae III and were grouped into 23 operational taxonomic units (OTUs). The estimate of library coverage showed that the library coverage value was of 73.6%, which indicated that the clone library could provide a fine inventory of bacterial diversity in the lake. Each representative clone of the 23 types was finally sequenced and homology analysis showed that the majority were affiliated to α-,β-, γ-Proteobacteria, Bacteroidetes, and Actinobacteria, which accounted for 10.3%, 41.4%, 4.6% and 6.9%, respectively. However, unlike bacterial composition of typical freshwater, the water had 10.3% of total bacteria slightly halo-and-alkaline-philic, making the composition unique. Moreover, 83.9% of total bacteria were lower than 97% of homology with cultured species, of which 58.9% were even failed to be identified at genus level, while ones (16.1% of total bacteria) affiliated to the cultured with the ability for pollutants degradation. Bacteroidetes and Firmicutes, and some groups of β-Proteobacteria came into dominant groups in the water, which could be the result of responding to the eutrophication.