title: Community structure and distribution of planktonic ammonia-oxidizing archaea and bacteria in the Dongjiang River, China.
abstract: Ammonia-oxidizing archaea (AOA) and bacteria (AOB) are widely distributed in the natural environment and play crucial roles in the nitrification process and the removal of nitrogen (N). Although planktonic microbial community plays an important role in river biogeochemical cycles, few studies have attempted to address the characteristics of AOA and AOB in the water column of river ecosystems. This study examined the community structures, distributions and abundance of planktonic AOA and AOB in the Dongjiang River and their responses to the changes in environmental parameters through quantitative polymerase chain reaction, cloning, and sequencing of ammonia mono-oxygenase (amoA). The abundance ratio of AOB to AOA varied from 0.07 to 9.4 along the river and was positively correlated with the concentration of ammonium. Significantly positive correlations were observed between the abundance of AOB and potential nitrification rates, which suggested that the contribution of AOB to nitrification was greater than that of AOA in the river. Phylogenetic analyses showed that AOA communities could be divided into three branches of Thaumarchaeota: Group 1.1a, Group 1.1a associated and Group 1.1b, with most sequences belonging to Group 1.1a. All AOB sequences fell within Nitrosomonas and Nitrosospira species, and the majority of sequences were affiliated with the latter. Multivariate statistical analyses indicated that the community distributions of AOA and AOB were significantly correlated with the concentrations of nitrate and total suspended solids, respectively. These findings fundamentally improved our understanding of the role of planktonic AOA and AOB in nitrogen cycling and their responses to changes in environmental factors in the river ecosystem.
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China; School of Life Sciences, Longyan University, Longyan 364000, China; State Key Laboratory of Applied Microbiology Southern China (The Ministry - Province Joint Development) South China, Guangzhou 510070, China. Electronic address: weiyu2005@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China; State Key Laboratory of Applied Microbiology Southern China (The Ministry - Province Joint Development) South China, Guangzhou 510070, China. Electronic address: xiachunyu2010@126.com.
authors.forename: Chunyu
authors.initials: C
authors.lastname: Xia
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China; State Key Laboratory of Applied Microbiology Southern China (The Ministry - Province Joint Development) South China, Guangzhou 510070, China. Electronic address: xumy@gdim.cn.
authors.forename: Meiying
authors.initials: M
authors.lastname: Xu
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China; State Key Laboratory of Applied Microbiology Southern China (The Ministry - Province Joint Development) South China, Guangzhou 510070, China. Electronic address: guojun@gzb.ac.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
authors.affiliation: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China; State Key Laboratory of Applied Microbiology Southern China (The Ministry - Province Joint Development) South China, Guangzhou 510070, China. Electronic address: guopingsun@163.com.
authors.forename: Guoping
authors.initials: G
authors.lastname: Sun
authors.affiliation: Harbin Institute of Technology, Harbin 150090, China. Electronic address: waj0578@hit.edu.cn.
authors.forename: Aijie
authors.initials: A
authors.lastname: Wang
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D064751:Ammonium Compounds / Q000032:analysis; D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D058448:Biota; D002681:China; D016000:Cluster Analysis; D008969:Molecular Sequence Data; D058465:Nitrification; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D045483:Rivers / Q000737:chemistry / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D064751:Ammonium Compounds; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase
keywords: Planktonic ammonia oxidizer; River ecosystem; amoA gene