南美白对虾养殖系统中氨氧化菌多样性研究

Study on the Diversity of Ammonia Oxidizing Bacteria in the Culture System of the Southern American White Prawn

[目的]为解决养殖水体的氨氮污染问题提供依据。[方法]研究南美白对虾养殖池塘底泥中的氨氧化菌的多样性和种群分布及其amoA基因的多样性,并与池塘周边土壤中的氨氧化菌群落结构进行比较。[结果]不同样品中氨氧化菌数量差异显著,其中池塘周边土壤中最多,达到4.5×105cfu/g,其次是池塘底泥和水体。来自土壤和底泥两个DNA样品均扩增到了预期长度(491 bp,517 bp)的amoA基因片段。底泥样品的DGGE条带数明显多于池塘周边土壤样品。土壤和底泥样品仅有1个共同的氨氧化菌种属,其序列与Nitrosospira sp.相似性达96%。池塘周边土壤的氨氧化菌种属序列与Nitrosospira sp.都有高度同源性。池塘底泥中Nitrosomonas sp.为氨氧化菌的优势菌群。[结论]构建的amoA基因克隆文库能较好反映南美白对虾养殖系统中氨氧化菌的多样性。

[ Objective] The research aimed to provide basis for solving the problem of ammonia nitrogen contamination in culture water. [ Method] The diversity and population distribution of ammonia oxidizing bacteria and the diversity of its amoA gene in the subsoil of the pond for culturing the southern American white prawn were studied. And it was compared with the community structure of ammonia oxidizing bacteria in the soil around the pond. [Resuit] The amount of ammonia oxidizing bacteria had a significant difference among different san,pies, in which that in the soil around the pond was most, reaching 4.5 × 10^5 cfu/g, following by pond subsoil and water body. The fragment of amoA gene with the expected length （491 bp,517 bp） was amplified from two DNA samples from both soil and the subsoil. The DGGE band number from the subsoil samples was obviously more than that from the soil sam- pies around the pond. The soil and subsoil samples only had 1 contain genera of ammonia oxidizing bacteria and its sequence similarity with Nitrosospira sp. reached 96%. The sequence of ammonia oxidizing bacteria genera in the soil around the pond all had higher horaology with Nitrosospira sp. Ni- trosospira sp. was the dominant bacteria in the subsoil of the pond. [ Conclusion] The established amoA gene clone library could better reflect the diversity of ammonia oxidizing bacteria in the culture system of the southern American white prawn.