华北典型旱地小麦土壤amoA基因的PCR-RFLP分析

PCR-RFLP analysis of amoA gene in wheat soil of North China

通过构建氨氧化细菌（AOB）和氨氧化古菌（AOA）的氨氧化酶基因亚基A（amoA）克隆文库，并采用限制性片段长度多态性（Restriction Fragment Length Polymorphism，RFLP）技术分析了华北地区典型早地冬小麦土壤中amoA基因的多样性。采用MspI和AfaI两种限制性内切酶对amoA基因克隆文库中阳性克隆子进行双酶切后，共得到了18个氨氧化细菌的可操作分类单元（Operational Taxa Units，OTUs）和10个氨氧化古菌可操作分类单元（Operational Taxa Units，OTUs），其文库覆盖率分别达到92．9％和88．3％。氨氧化细菌的Shannon-Wiener指数、丰富度指数、均匀度指数均高于氨氧化古菌。通过对文库中amoA细菌测序分析，所有的序列都属于Nitrosospira cluster3。而在氨氧化古菌中存在着一个绝对优势种群，它占到克隆文库的80％，测序分析的结果表明，氨氧化古菌属于不可培养的泉古菌门。

Ammonia-oxidizing microbes play an important role in the biogeochemical cycle of N element and it is also the limited rate of nitrification. The ammonia monooxygenase subunit A（amoA） diversity in winter wheat soil of northern China was researched through amo.4 clone library. There are 18 OTUs （Operational Taxa Units） in ammonia oxidizing bacteria library and 10 OTUs in ammonia oxidizing archea library by MspI and AfaI digestion analysis. The clone coverage ofamoA bacteria is 92.9% and that ofamoA archea is 88.3%. The Shannon-Wiener index, evenness index and richness index of ammonia-oxidizing bacteria （AOB） are higher than those of ammonia-oxidizing archaea （AOA）. The sequences of AOB clones belong to Nitrosospira.cluster 3. But in the amo.4 archea clones, there is only one absolutely dominant OTU and it reaches 80% in the clones. The sequence of the dominant amoA archaea OTU belongs to a uncultured crenarchaeote.