珠三角养殖水体中参与氮循环的微生物群落结构

Microbial community in nitrogen cycle of aquaculture water of the Pearl River Delta

【目的】为了研究珠三角地区养殖水体中各种含氮化合物循环转化的特征及其相关功能微生物的群落结构。【方法】构建人工模拟养殖系统,采用15N-稳定性同位素探测技术(stable isotope probing,15N-SIP)标记参与氮素迁移的微生物,通过氯化铯-溴化乙锭密度梯度超高速离心法分离15N标记的DNA,并以此构建含15N-DNA的细菌和古菌16S rRNA基因克隆文库。【结果】15N标记的基因组DNA经过超高速密度梯度离心后成功与14N-DNA分离;对克隆文库序列的分析表明:细菌文库得到的19个可操作分类单元(Operational TaxaUnits,OTUs)分别归为变形菌门(Proteobacteria)和浮霉菌门(Planctomycetes)。变形菌门为绝对优势类群,占整个细菌克隆文库的99.2%,其中优势菌群为丛毛胞菌属(Comamonas)(15.7%)、亚硝化单胞菌属(Nitrosomonas)(12.4%)、肠杆菌科(Enterobacteriaceae)(11.5%)和硝化杆菌属(Nitrobacter)(11.5%);古菌文库得到的9个OTUs归为奇古菌门(Thaumarchaeota)、泉古菌门(Crenarchaeota)和广古菌门(Euryarchaeota)。【结论】将15N-SIP技术应用于珠三角养殖水体氮素循环微生物群落结构的研究中,得到了丰富的氮素循环微生物群落的组成,这些信息为进一步分离纯化氮素降解微生物提供了重要的参考,为营造健康的水产养殖环境提供科学依据。

[Objective] In order to study the characteristic of nitrogen transport,the community structure and diversity of related microorganisms in aquaculture water of the Pearl River Delta.[Methods] We established an artificial aquaculture ecosystem to study the microbial community of 15N-stable isotope probing（15N-SIP） labeled nitrogen transport microorganisms.The 15N-labeled DNA was separated by CsCl-ethidium bromide density gradient centrifugation,and was used to construct 16S rRNA gene clone libraries of bacteria and archaea.[Results] Phylogenetic analysis shows that 19 Operational Taxonomic Units（OTUs） from bacterial library were clustered in Proteobacteria and Planctomycetes.Proteobacteria（99.2%） was the dominant group,mainly consisted of Comamonas（15.7%）,Nitrosomonas（12.4%）,Enterobacteriaceae（11.5%） and Nitrobacter（11.5%）.From archaeal library 9 OTUs were divided into 3 phyla： Thaumarchaeota,Crenarchaeota and Euryarchaeota.[Conclusion] We successfully elucidated the microbial community of nitrogen transport microorganisms in aquaculture water of Pearl River Delta by using 15N-SIP.The data of the community will provide essential information for isolating nitrogen degrading microorganism,and provide scientific basis for creating a healthy aquaculture environment.