Nitrification is a key process in nitrogen cycling, which has received considerable attention in the research field of soil biochemistry. In 2015, the discovery of complete ammonia oxidizers (Comammox) challenged conventional two-step nitrification perspective, which represented a paradigm shift in the understanding of soil nitrogen cycling. Comammox are a group of microorganisms capable of conducting both steps of nitrification. In this review, we summarized current understan-ding of the molecular ecology of comammox, including specific molecular biomarkers for comammox, phylogenetic and genomic surveys of comammox and particularly the distribution, diversity and ecological significance of comammox in soil. Further studies should focus on: 1) designing specific molecular biomarkers to examine the distribution and diversity of comammox; 2) optimizing cultivation techniques to isolate/enrich comammox cultures and expending our insights into physiological traits of comammox; 3) characterizing their distribution and in situ activities to elucidate the contribution of comammox processes to soil nitrification and their ecological features, which may assist in unco-vering the mechanisms of nitrogen cycling and promote the environmental protection of soil ecosystem.
硝化作用是氮素循环的核心环节,一直是土壤生物化学研究的热点之一。2015年,完全氨氧化菌(Comammox)的发现颠覆了两步硝化的传统观点,丰富了土壤氮素循环的理论体系。完全氨氧化菌能够独立执行整个硝化过程,具有将氨直接氧化成硝酸盐的能力。本文从完全氨氧化菌的定量检测方法、系统发育及组学分析入手对其分子生态学的国内外研究进展进行了系统综述,着重阐述了完全氨氧化菌在土壤中的多样性和分布规律。未来的研究可以针对以下内容开展:1)探索完全氨氧化菌的分子标志物,设计特异性引物,使其具有更高的分子覆盖度,从而完善完全氨氧化菌多样性的研究;2)优化完全氨氧化菌分离培养技术,富集分离得到更多完全氨氧化菌富集物或纯培养,完善完全氨氧化菌生理生化特性的研究;3)对完全氨氧化菌的功能和活性进行原位表征,并解析其对土壤硝化过程的贡献,阐明完全氨氧化菌的生态学特征,为促进土壤氮素良性循环和生态环境保护提供科学依据。.
Keywords: DNA primer; Nitrospira; comammox; genomics; nitrification inhibitor; phylogenetic analysis.