典型对虾养殖水体中参与硝化与反硝化过程的微生物群落结构

Community structure of microbes involved in nitrification and denitrification in typical shrimp-farming water

摘要:

摘要:【目的】本研究旨在分析典型虾塘养殖水体中参与氮循环关键过程的菌群多样性，为指导实际对虾养殖水体中NH+4和NO－2的微生物降解、水体氮素污染控制以及虾塘养殖氮素循环的有效管理提供科学依据。【方法】使用聚合酶链式反应及变性梯度凝胶电泳技术(Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis，PCR-DGGE)从8 个不同地点的虾塘水样中确定代表性水样，以此为典型水样进行研究，构建了氨单加氧酶基因(amoA)、亚硝酸盐氧化还原酶基因(nxrA)、亚硝酸盐还原酶基因(nirS)的克隆文库。利用限制性片段长度多态性(Restriction Fragment Length Polymorphism，RFLP) 技术将克隆文库进行酶切分析。【结果】通过序列多态性分析，表明amoA 基因克隆文库中所有序列都属于变形杆菌门β 亚纲(β-Proteobacteria)，分别为亚硝化单细胞菌属(Nitrosomonas)(81%)和亚硝化螺旋菌属(Nitrosospira) (19%)2个属。nxrA 基因克隆文库检测到α-Proteobacteria 和δ-Proteobacteria 两个亚纲，其中硝化杆菌属(Nitrobacter)是优势菌群，占整个文库的92%，仅有一个类群属于δ亚纲的脱硫杆菌科(Desulfobacteraceae) (8%)。nirS 基因文库群落结构相对于amoA和nxrA 基因文库较复杂，分别为α-Proteobacteria、β-Proteobacteria亚纲和Actinobacteria，序列分析表明，25% 的类群为固氮弧菌属(Azoarcus)，25%的类群为(Polymorphum),20%的类群为需氧去氮菌属(Thauera)，10% 的类群为(Sophophora)，10% 的的类群为链霉菌属(Streptomyces)，5%的类群为(Brachymonas)，5%的类群为(Ruegeria)。【结论】典型虾塘养殖水环境中氮素循环关键过程的菌群多样性丰富，其中亚硝化单胞菌属(Nitrosomonas)和硝化杆菌属(Nitrobacter)分别是此环境中主要的氨氧化作用推动者和亚硝酸盐氧化作用推动者，而在反硝化重要环节中，固氮弧菌属等多种菌群都起着推动作用。

Abstract:

Abstract: ［Objective］We analyzed the community and diversity of microorganisms involved in nitrification and denitrification of nitrogen cycle in typical aquaculture water in order to manage microbiological degradation of NH+4 and NO－2，to control nitrogen pollution and nitrogen cycle in shrimp-farming water． ［Methods］ Samples were analyzed by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) graph． We constructed clone libraries of the typical sample based on the functional gene ammonia monooxygenase gene (amoA)，nitrite oxidoreductase gene (nxrA)，and nitrite reductase gene (nirS)．These three libraries were analyzed by using Restriction Fragment Length Polymorphism (RFLP)． ［Results］Phylogenetic analysis showed that all sequences from amoA library were clustered into β-Proteobacteria，including Nitrosomonas (81%) and Nitrosospira (19%)．Clones from nxrA library were clustered into α-Proteobacteria and δ-Proteobacteria，including Nitrobacter (92%) and Desulfobacteraceae (8%)．Clones from nirS library were clustered into α-Proteobacteria，β-Proteobacteria and Actinobacteria．β-Proteobacteria was the dominant group that consisted of Azoarcus (25%)，Brachymonas (5%)，and Thauera (20%)．In α-Proteobacteria group，Sophophora (10%)，Polymorphum (25%)，Ruegeria (5%) were detected． In the Actinobacteria group，Streptomyces (10%) was detected．［Conclusion］ Microorganisms involved in nitrification and denitrification of nitrogen cycle were abundant． In the aquaculture water，Nitrosomonas was the main performer of ammoxidation，Nitrobacter was the main performer of nitrification，and many kinds of populations played important roles in the denitrification．