School of Bioscience and Bioengineering, South China University of Technology.
Microbes Environ. 2013;28(4):457-65. doi: 10.1264/jsme2.me13066. Epub 2013 Nov 19.
Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrification. However, limited information about the characteristics of AOA and AOB in the river ecosystem is available. The distribution and abundance of AOA and AOB in the sediments of the Dongjiang River, a drinking water source for Hong Kong, were investigated by clone library analysis and quantitative real-time PCR. Phylogenetic analysis showed that Group 1.1b- and Group 1.1b-associated sequences of AOA predominated in sediments with comparatively high carbon and nitrogen contents (e.g. total carbon (TC) >13 g kg(-1) sediment, NH4(+)-N >144 mg kg(-1) sediment), while Group 1.1a- and Group 1.1a-associated sequences were dominant in sediments with opposite conditions (e.g. TC <4 g kg(-1) sediment, NH4(+)-N <93 mg kg(-1) sediment). Although Nitrosomonas- and Nitrosospira-related sequences of AOB were detected in the sediments, nearly 70% of the sequences fell into the Nitrosomonas-like B cluster, suggesting similar sediment AOB communities along the river. Higher abundance of AOB than AOA was observed in almost all of the sediments in the Dongjiang River, while significant correlations were only detected between the distribution of AOA and the sediment pH and TC, which suggested that AOA responded more sensitively than AOB to variations of environmental factors. These results extend our knowledge about the environmental responses of ammonia oxidizers in the river ecosystem.
氨氧化古菌（AOA）和细菌（AOB）在硝化作用中发挥着重要作用。然而，有关河流生态系统中 AOA 和 AOB 特征的信息有限。通过克隆文库分析和定量实时 PCR 研究了香港饮用水源东江沉积物中 AOA 和 AOB 的分布和丰度。系统发育分析表明，在碳氮含量较高的沉积物中（如总碳（TC）>13 g kg(-1) 沉积物，NH4(+)-N >144 mg kg(-1) 沉积物），AOA 以 1.1b 组和 1.1b 相关序列为主，而在相反条件的沉积物中（如 TC <4 g kg(-1) 沉积物，NH4(+)-N <93 mg kg(-1) 沉积物），AOA 以 1.1a 组和 1.1a 相关序列为主。尽管在沉积物中检测到了硝化菌和硝化螺菌相关的 AOB 序列，但近 70%的序列属于硝化菌样 B 群，表明河流沿线的沉积物 AOB 群落相似。在东江几乎所有的沉积物中，AOB 的丰度都高于 AOA，而仅在 AOA 的分布与沉积物 pH 值和 TC 之间检测到显著相关性，这表明 AOA 对环境因素的变化比 AOB 更敏感。这些结果扩展了我们对河流生态系统中氨氧化菌环境响应的认识。
