单步硝化作用与全程氨氧化微生物研究进展  

Progress in understanding of one-step nitrification(complete ammonia oxidizing)microorganisms:A review

作　　者：石秀丽 郭萌萌[2,3] 张莹 秦华[1] 万琪慧[2,4] 谢德体 蒋先军[2,4] SHI Xiu -li;OUO Meng -meng;ZHANG Ying;QIN Hua;WAN Qi -hui;XIE De- ti;JIANG Xian- jun(College of Horticulture and Landscape, Southwest University, Chongqing 400715, China;Research Center for Soil Biology Southzvest University, Chongqing 400715, China;Academy of Agriculture, Southwest University, Chongqing 400715, China 4. College of Resources and Environment, Southwest University, Chongqing 400715, China)

机构地区：[1]西南大学园艺园林学院,重庆400715 [2]西南大学土壤生物研究中心,重庆400715 [3]西南大学农业研究院,重庆400715 [4]西南大学资源环境学院,重庆400715

出　　处：《草业学报》2018年第7期196-203,共8页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(41671232);国家重点研发计划(2016YFD0300901)资助

摘　　要：单步硝化作用,即由一种微生物(全程氨氧化微生物)单独完成将NH3氧化为NO3-的整个硝化过程,于2015年底被发现。该发现终结了传承百年的两步硝化作用的经典理论,并引发了众多关于全球氮素循环的重要科学问题。就单步硝化作用及全程氨氧化微生物发现后两年来的研究进展进行概述。目前已确定的全程氨氧化微生物均属于硝化螺菌门谱系Ⅱ(Nitrospiraspp.LinageⅡ),包括两个分支A和B(Clade A和Clade B);广泛分布于农业土壤、森林土壤、稻田水域、淡水等自然环境中。全程氨氧化细菌(Nitrospira inopinata)比大多数可培养的氨氧化细菌(AOB)以及氨氧化古菌(AOA)物种对氨具有更高的亲和力,能够更好地适应极低氨浓度环境。此外,全程氨氧化微生物具有不同的碳氮代谢途径,可能具有和其他氨氧化微生物不同的生态位点。单步硝化作用的相对贡献与全程氨氧化微生物的生态位分化是今后的重要研究方向。One-step nitrification whereby the whole process of nitrification from NH3 to NO3-is completed by one microorganism（complete ammonia oxidizers;comammox）,was first reported in late 2015.The discovery of one-step nitrification and comammox,ended a 100-year-old belief that biological nitrification was necessarily a two-step process,and raised many important scientific questions about the implications for the global nitrogen cycle,such as the ecological niche of these microorganisms in the environment and their relative contribution to nitrification.This study briefly reviews the progress in understanding one-step nitrification and comammox during the past two years.The reported comammox are all members of the genus Nitrospiraspp.LinageⅡ,including two clades（A and B）.They are widely distributed in agricultural soils,forest soils,paddy and fresh water environments.The comammox Nitrospira inopinata has a much higher affinity for ammonia than most cultured ammonia-oxidizing bacteria（AOB）and ammonia-oxidizing archaea（AOA）,which confers them a competitive advantage in ammonia-limited environments.This finding changed our view of the potential role of complete ammonia oxidizers in nitrification.Rather than being rare organisms inhabiting peripheral habitats,it turns out that comammox bacteria are well adapted to the low ammonia environments that characterize most of the world＇s biosphere.Additionally,the comammox members of Nitrospirapossess different C and N metabolism pathways compared to AOA and AOB,and thus may also have different ecological roles or niches in the environment.The relative contribution of one-step and two-step nitrification pathways in different environments and the niche differentiation of comammox will be important fields for future study.So far,only a few ecosystems have been studied for the abundance of comammox,but the studies to date demonstrate that these microbes are widely distributed in low-ammonia environments.There is now an urgent need to determine their contribution to

关 键 词：NITROSPIRA 亚硝酸氧化细菌 氨氧化微生物 氮循环 

分 类 号：Q93[生物学—微生物学]