Graduate School of Agricultural and Life Sciences, The University of Tokyo.
Jiangsu University.
Microbes Environ. 2020;35(1). doi: 10.1264/jsme2.ME19064.
Recent studies demonstrated that phylogenetically more diverse and abundant bacteria and fungi than previously considered are responsible for denitrification in terrestrial environments. We herein examined the effects of land-use types on the community composition of those denitrifying microbes based on their nitrite reductase gene (nirK and nirS) sequences. These genes can be phylogenetically grouped into several clusters. We used cluster-specific PCR primers to amplify nirK and nirS belonging to each cluster because the most widely used primers only amplify genes belonging to a single cluster. We found that the dominant taxa as well as overall community composition of denitrifying bacteria and fungi, regardless of the cluster they belonged to, differed according to the land-use type. We also identified distinguishing taxa based on individual land-use types, the distribution of which has not previously been characterized, such as denitrifying bacteria or fungi dominant in forest soils, Rhodanobacter having nirK, Penicillium having nirK, and Bradyrhizobium having nirS. These results suggest that land-use management affects the ecological constraints and consequences of denitrification in terrestrial environments through the assembly of distinct communities of denitrifiers.
最近的研究表明，与先前认为的相比，在陆地环境中进行反硝化作用的细菌和真菌在系统发育上更加多样化和丰富。本研究基于亚硝酸盐还原酶基因（nirK 和 nirS）序列，调查了土地利用类型对这些反硝化微生物群落组成的影响。这些基因可根据其系统发育分为几个聚类。由于最常用的引物仅扩增属于单个聚类的基因，因此我们使用聚类特异性 PCR 引物来扩增属于每个聚类的 nirK 和 nirS。研究发现，反硝化细菌和真菌的优势类群以及整个群落组成，无论其所属聚类如何，都因土地利用类型而异。我们还根据单个土地利用类型确定了具有区分度的分类群，其中一些分类群的分布以前尚未被描述，例如在森林土壤中占优势的反硝化细菌或真菌、具有 nirK 的 Rhodanobacter、具有 nirK 的 Penicillium 和具有 nirS 的 Bradyrhizobium。这些结果表明，土地利用管理通过组装不同的反硝化菌群落，影响陆地环境中反硝化作用的生态约束和后果。
