Abstract: To explore the bacteria community structure and it’s relation with water quality in polluted rivers, water and sediment samples were collected from Buji River (Shenzhen) in dry season. Quantification of total bacteria and denitrifying bacteria based on nosZ and narG gene were performed by real-time PCR, and the microbial community structures were studied by PCR-DGGE. The results show that the total bacteria 16S rRNA fragment changed from 5.77×10⁸ to 7.13×10¹¹ copies/L in water samples and from 1.14×10⁹ to 1.61×10¹¹ copies/g in sediments. The copy numbers of nosZ gene varied from 2.99×10⁶ to 9.39×10⁸ copies/L in water samples, and from 1.52×10⁶ to 3.80×10⁷ copies/g in sediments. The copy numbers of narG gene were in the range from 1.45×10⁷ to 9.11×10⁹ copies/L in water samples and 2.38×10⁷ to 2.93×10⁸ copies/g in sediments. The gene abundance of nosZ and narG genes in sediment was higher than that in water. Redundancy discrimination analysis (RDA) shows that Fe was the main factor influencing the numbers of bacteria, while COD, nitrite, and nitrate were the main factors affecting the microbial community structures in Buji River. The diversity of bacteria in water samples was higher than that in sediments.

Key words: real-time PCR, DGGE, total bacteria, denitrifying bacteria, Buji River

摘要： 为了研究污染河流中微生物群落结构的存在状况及与水环境因子的关系, 以深圳市深圳河的一级支流布吉河为研究对象, 采用DGGE和Q-PCR技术分析了布吉河不同断面水样和沉积物中总细菌数量和群落结构以及反硝化基因(nosZ和narG基因)数量变化。结果表明, 水样中总细菌数量的变化范围为5.77×10⁸~ 7.13×10¹¹ copies/L, nosZ和narG基因数量的变化范围分别为2.99×10⁶~9.39×10⁸ copies/L和1.45×10⁷~9.11×10⁹ copies/L。沉积物中总细菌数量的变化范围为1.14×10⁹~1.61×10¹¹ copies/g, nosZ和narG基因数量的变化范围分别为1.52×10⁶~3.80×10⁷ copies/g和2.38×10⁷~2.93×10⁸ copies/g。由于生境的差异, 沉积物中nosZ和narG基因丰度高于水样。冗余度分析表明, 影响微生物数量和群落结构的水环境因子不同, Fe是影响布吉河水样中细菌数量的主要水环境因子, 而COD、亚硝氮和硝氮是影响布吉河微生物群落结构的主要水环境因子。水样和沉积物中微生物生态功能都很稳定, 但水样中总细菌多样性比沉积物中高。

关键词: 荧光定量PCR, DGGE, 总细菌, 反硝化细菌, 布吉河