西南印度洋深海热液羽流海水细菌的多样性

Bacterial diversity in a deep-sea hydrothermal plume in the southwest Indian Ocean

摘要:

摘要:【目的】分析西南印度洋深海热液羽流细菌的多样性特点，为认识该特殊环境微生物对大洋生态系统的影响，以及获得特殊的微生物资源奠定基础。【方法】将西南印度洋深海热液羽流海水进行原位浓缩，对获得的1000 倍浓缩海水样品进行富集培养和微生物纯培养;通过构建原始海水浓缩样品和富集培养物的16S rRNA基因克隆文库，结合纯培养获得的微生物菌株的16S rRNA基因，分析该样品的细菌多样性结构和特点。【结果】共获得104个16S rRNA基因，其中50个来自原始热液羽流浓缩海水样品，40个来自富集培养物，14个来自分离获得的纯培养，它们分属于γ-变形菌群(γ-Proteobacteria) (74个)，α-变形菌群(α-Proteobacteria) (14个)，β-变形菌群(β-Proteobacteria) (5个)，拟杆菌群(Bacteroidetes) (4 个)，厚壁菌群(Firmicutes) (2个)，浮霉状菌(Planctomycetes) (2个)，疣微菌(Verrucomicrobia) (2个)以及放线菌(Actinobacteria) (1 个)，共29个不同的操作分类单元(Operational Taxonomic Units，OTUs)。26 个序列与已知微生物16S rRNA 基因相似性低于97%，最低的只有86%。【结论】西南印度洋热液羽流存在较丰富的微生物多样性，以γ-Proteobacteria 为优势类群，其次为α-Proteobacteria;该环境中存在较多尚未获得分离培养 的微生物新属种。

Abstract:

Abstract:［Objective］We characterized bacterial diversity in a deep-sea hydrothermal plume seawater in the southwest Indian Ocean to increase our understanding of the impact of the microorganisms on the ocean ecosystem and to survey microbial resources in this special environment． ［Methods］The deep-sea hydrothermal plume seawater in the southwest Indian Ocean was concentrated in situ by 1000 folds，enrichment cultures were established with the concentrated sample，and isolates were purified． Bacterial 16S rRNA gene libraries were constructed from both the concentrated seawater sample and from the enrichment culture and analyzed． The 16S rRNA genes from the isolated strains were also analyzed．［Results］A total of 104 16S rRNA genes were obtained，in which 50 were from the concentrated plume seawater，40 from the enrichment culture，and 14 from the isolated strains． These sequences are affiliated with γ-proteobacteria (74)，α-proteobacteria (14)，β-Proteobacteria(5)，Bacteroidetes (4)，Firmicutes (2)，Planctomycetes (2)，Verrucomicrobia (2) and Actinobacteria (1)，and fall into 29 different operational taxonomic units (OTUs)． Twenty-six sequences share less than 97% identity with the best-matched sequences in the public database，with the lowest being 86%．［Conclusions］There is rich bacterial diversity in the deep-sea hydrothermal plume seawater in the southwest Indian Ocean，where γ-proteobacterial groups were dominant，followed by α-proteobacterial groups．A number of species remain uncultured．