黄东海沉积物细菌的分类及多样性研究

Benthic biosphere is the most complex habitat for microbe and contains abundant bacterial resource. However, bacterial species and geographical distribution of bacterial community in the sediment of the Yellow Sea and East China Sea are still little known. This study takes the benthic sediments collected from the Yellow Sea and East China Sea as research materials. Marine bacteria are isolated by culture-dependent methods and further characterized by the taxonomic and phylogenetic studies. The potential novel isolates are identified by a polyphasic taxonomic approach. The bacterial species resource in the sediment of the Yellow Sea and East China Sea will be investigated. Culture-independent methods(clone library and PCR-DGGE) are used to analyze community structure of marine bacteria among different sites. The geographical distribution of bacterial community in the sediment of the Yellow Sea and East China Sea will be illustrated. The implementation of this study will promote the development of marine bacterial taxonomy, and provide scientific basis for utilization of marine bacterial resource of our country.

海底生物圈是最复杂的微生物栖息地，蕴藏着丰富的细菌资源，但我国黄东海沉积物中细菌物种资源和细菌群落的地理分布还不清楚。本课题以黄东海沉积物为研究对象。采用培养方法分离海洋细菌，并进行分类学和系统发育研究，根据多相分类原则分类鉴定潜在的细菌新物种，调查我国黄东海沉积物的细菌物种资源；采用基因文库和PCR-DGGE等非培养方法，研究不同站位细菌的群落结构，阐明黄东海沉积物中细菌群落的地理分布特征。本课题的开展将促进我国海洋细菌分类学的发展，为开发利用我国海洋细菌资源提供重要的科学依据。

本研究以黄东海海域37个站位的海底沉积物为研究对象，采用培养和非培养的手段，研究我国黄东海沉积物细菌的多样性。. 通过培养的手段，共获得561株可培养细菌，选取了421株进行测序分析，结果表明，421株菌归于4个门（厚壁菌门、变形菌门、放线菌门和拟杆菌门），48个属，121个种。其中厚壁菌门在数量和种类上占绝对优势，占分离总数的68%，最大优势菌属为芽孢杆菌属，占总数的45%。另外有14株可能为海洋细菌的新属或新种。目前已在IJSEM期刊正式发表一个新种Gelidibacter sediminis ，新种Virgibacillus flavescens 被IJSEM期刊接受发表。另外2个新种的文章正在评审修改中。. 本研究采用新一代Illumina方法研究黄东海表层沉积物样品中不同站位的微生物群落组成和结构，一共3,771,648 条序列被分为22,746个分类单元，属于67个细菌门（包括41个未培养的门）和2个古菌门，243个纲和982个属。原核微生物群落主要包括4个主要的门（Proteobacteria, Planctomycetes, Crenarchaeota and Bacteroidetes），其中变形菌门（主要为γ变形菌门和δ变形菌门）是优势类群。古菌的种类远小于细菌种类，主要为泉古菌门（Crenarchaeota）和广古菌门（Euryarchaeota）。浮霉状目属Planctomyces和亚硝化侏儒菌属Nitrosopumilus是主要的细菌和古菌属，广泛分布在黄东海各个站位样品中。对原核微生物群落结构和环境变量采用多元统计分析（Multivariate statistical analyses）和相关性分析，结果表明，温度和沉积物粘土含量为影响黄东海沉积物原核微生物群落分布的主要原因。