• 关键词：硝酸盐异化还原成铵过程  高通量测序  功能基因nrfA  旱地农田土壤  根际和非根际

• 基金项目：国家自然科学基金（No.41671471，41322012，21707155）；中国科学院的战略重点研究项目（No.XDB15020303）；国家重点研发项目（No.2016YFA0602303）；广东省"珠江人才计划"本土创新科研团队项目（No.2017BT01Z176）；环境模拟与污染控制国家重点联合实验室专项资金（生态环境科学研究中心，中国科学院）（No.18Z02ESPCR），中国科学院饮用水科学与技术重点实验室开放研究基金（No.16Z03KLDWST）；中国科学院创新团队国际合作伙伴计划

• 周利
• 青岛理工大学环境与市政工程学院, 青岛 266033

• 王晓侠
• 1. 青岛理工大学环境与市政工程学院, 青岛 266033;2. 中国科学院生态环境研究中心饮用水科学与技术重点实验室, 北京 100085

• 周立光
• 中国科学院生态环境研究中心饮用水科学与技术重点实验室, 北京 100085

• 皮艳霞
• 1. 中国科学院生态环境研究中心饮用水科学与技术重点实验室, 北京 100085;2. 哈尔滨商业大学生命科学与环境研究中心, 哈尔滨 150028

• 周杰民
• 中国科学院生态环境研究中心饮用水科学与技术重点实验室, 北京 100085

• 祝贵兵
• 中国科学院生态环境研究中心饮用水科学与技术重点实验室, 北京 100085

• 摘要：为研究典型旱地农田土壤硝酸盐异化还原成铵过程（Dissimilatory nitrate reduction to ammonium，DNRA）的群落组成，针对DNRA过程的功能基因nrfA进行高通量测序.根际和非根际、4种典型农作物共16个样品，质控后每个样品得到87000条序列，在相似度 ≥ 90%下划分到27952个OTUs，选取其中丰度较高的258个代表OTUs进行生态学分析.多样性分析（OTUs水平）结果表明：3/4的作物根际土壤样品中的DNRA群落丰富度、物种多样性和物种均匀度高于相应非根际样品，对比4种作物，粟作物根部土壤DNRA群落多样性最高，玉米作物非根际土壤最低.对代表OTUs进行分类，共定义到6个门（Phylum），19个属（Genus）.其中相对丰度最高的3个属为Hyalangium（29.31%）、Chthoniobacter（20.33%）和Nitrospira（13.41%），表明三者在群落组成中占主导地位.结合土壤理化因子分析，DNRA群落相对丰度与NO₂^--N、TN、含水率、TOM、pH及温度呈显著相关关系.本研究在一定程度上揭示了旱地农田土壤DNRA细菌的群落组成、多样性及与土壤环境因子的关系，为提高氮肥的利用效率和减小环境污染提供理论依据.

• Abstract：To explore the community composition of dissimilatory nitrate reduction to ammonium (DNRA) process in typical agricultural dryland soil, high-throughput sequencing targeting on the functional gene nrfA of DNRA bacteria was carried out. A total of 16 samples of rhizosphere and non-rhizosphere soils from 4 typical agricultural lands were collected, and 87000 sequences were obtained for each sample after quality control. Then these sequences were clustered to 27952 OTUs with similarity above 90%, of which 258 representative OTUs with higher abundance were selected for community analysis. Results of diversity analysis (OTUs level) demonstrated that 3/4 of the samples in rhizosphere soil had a higher diversity, richness, and species uniformity of DNRA community than those in the corresponding non-rhizosphere soils. Moreover, it was found that rhizosphere soil of millet crops had the highest diversity of DNRA community while non-rhizosphere soil of maize crops had the lowest one among the investigated crops. Furthermore, the representative OTUs was classified into 6 phyla and 19 genera, and, the three highest richness genera were Hyalangium (29.31%), Chthoniobacter (20.33%) and Nitrospira (13.41%), indicating their dominant role in DNRA community composition. Combined with soil physicochemical factor analysis, the relative abundance of DNRA community was significantly correlated with NO₂^--N, TN, moisture content, TOM, pH and temperature in the four crops. To some extent, this study revealed the community composition, diversity of DNRA bacteria, and their relationship with soil environmental factors in agricultural dryland soil, providing theoretical basis for improving the utilization efficiency of nitrogen fertilizer and reducing environmental pollution.

• Key words：dissimilatory nitrate reduction to ammonium (DNRA)  high-throughput sequencing  nrfA functional gene  arid farmland soil  rhizosphere and non-rhizospher

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