The Microbial Community Structure of Relict Niter-beds Previously Used for Saltpeter Production

这些硝石是在白川乡和五山县的一个历史村庄里，利用煤气屋地板下形成的硝床工艺生产的。在这些废弃的氮床土壤中，硝化微生物的多样性尚不清楚。本研究采用焦磷酸测序技术，以16S rRNA基因和氨单加氧酶基因（amoA）为靶点，对废硝床土壤进行微生物组合分析。16S rRNA基因分析表明，变形菌门、放线菌门和拟杆菌门的成员是主要的微生物成分，主坐标分析表明土壤离子含量是群落的关键因素。amoA热tag分析显示，硝化菌属和亚硝化菌属（Ca. Nitrososphaera）占主导地位，土壤pH和有机碳含量是影响硝化微生物生态位的重要因素。这些结果表明，这些生物可能在废硝层土壤生态系统中发挥氨氧化作用。

The saltpeter had been produced by using niter-bed process formed under the floor of gassho-style house in a Historic Village of Shirakawa-go and Gokayama. The diversity of the nitrifying microbes in such relict niter-bed soil remains unclear. Here, the microbial assemblages of relict niter-bed soils were performed by pyrosequencing analysis targeting 16S rRNA gene and ammonia monooxygenase gene (amoA). The 16S rRNA gene analyses revealed that members of the phyla Proteobacteria, Actinobacteria, and Bacteroidetes were major microbial constituents, and principal coordinate analysis showed that soil ion contents were critical factors for the communities. The amoA pyrotag analysis revealed that Nitrosospira and "Ca. Nitrososphaera" predominated, and soil pH and organic carbon content were important factors for the ecological niche of nitrifying microbes. These results suggest that these organisms may play roles in ammonia-oxidation in relict niter-bed soil ecosystems.