Wang Jichen, Ni Lei, Song Yang, Rhodes Geoff, Li Jing, Huang Qiwei, Shen Qirong
Jiangsu Provincial Key Lab and Coordinated Research Center for Organic Solid Waste Utilization, Nanjing Agricultural UniversityNanjing, China.
Department of Plant, Soil and Microbial Sciences, Michigan State UniversityEast Lansing, MI, USA.
Front Microbiol. 2017 Apr 12;8:630. doi: 10.3389/fmicb.2017.00630. eCollection 2017.
Ammonia oxidation by microorganisms is a rate-limiting step of the nitrification process and determines the efficiency of fertilizer utilized by crops. Little is known about the dynamic response of ammonia-oxidizers to different fertilization regimes in a wheat-rice rotation system. Here, we examined ammonia-oxidizing bacteria (AOB) and archaea (AOA) communities across eight representative stages of wheat and rice growth and under four fertilization regimes: no nitrogen fertilization (NNF), chemical fertilization (CF), organic-inorganic mixed fertilizer (OIMF) and organic fertilization (OF). The abundance and composition of ammonia oxidizers were analyzed using quantitative PCR (qPCR) and terminal restriction fragment length polymorphism (T-RFLP) of their genes. Results showed that fertilization but not plant growth stages was the best predictor of soil AOB community abundance and composition. Soils fertilized with more urea-N had higher AOB abundance, while organic-N input showed little effect on AOB abundance. 109 bp T-RF ( Cluster 3b) and 280 bp T-RF ( Cluster 3c) dominated the AOB communities with opposing responses to fertilization regimes. Although the abundance and composition of the AOA community was significantly impacted by fertilization and plant growth stage, it differed from the AOB community in that there was no particular trend. In addition, across the whole wheat-rice rotation stages, results of multiple stepwise linear regression revealed that AOB played a more important role in ammonia oxidizing process than AOA. This study provided insight into the dynamic effects of fertilization strategies on the abundance and composition of ammonia-oxidizers communities, and also offered insights into the potential of managing nitrogen for sustainable agricultural productivity with respect to soil ammonia-oxidizers.
微生物对氨的氧化是硝化过程中的限速步骤，决定了作物对肥料的利用效率。在稻麦轮作系统中，关于氨氧化菌对不同施肥制度的动态响应知之甚少。在此，我们研究了小麦和水稻生长的八个代表性阶段以及四种施肥制度下的氨氧化细菌（AOB）和古菌（AOA）群落：不施氮肥（NNF）、化肥（CF）、有机无机混合肥料（OIMF）和有机肥（OF）。利用定量PCR（qPCR）及其基因的末端限制性片段长度多态性（T-RFLP）分析了氨氧化菌的丰度和组成。结果表明，施肥而非植物生长阶段是土壤AOB群落丰度和组成的最佳预测指标。施用更多尿素氮的土壤AOB丰度更高，而有机氮输入对AOB丰度影响不大。109 bp的T-RF（簇3b）和280 bp的T-RF（簇3c）在AOB群落中占主导地位，对施肥制度有相反的响应。虽然AOA群落的丰度和组成受到施肥和植物生长阶段的显著影响，但其与AOB群落不同，没有特定趋势。此外，在整个稻麦轮作阶段，多元逐步线性回归结果表明，AOB在氨氧化过程中比AOA发挥更重要的作用。本研究深入了解了施肥策略对氨氧化菌群落丰度和组成的动态影响，也为基于土壤氨氧化菌管理氮素以实现可持续农业生产力提供了见解。
