微生物介导的氮代谢途径对维持土壤生态系统的结构和功能稳定性具有重要作用。阐明微生物群落与氮代谢途径之间的关系可以在微观水平上扩展我们对氮代谢途径的理解。然而,微生物的水平基因转移意味着基于分类学的方法不能轻易应用。越来越多的研究表明,功能特征会影响社区建设和生态系统功能。利用基于功能性状的土壤微生物群落研究方法,因此,更好地表征氮代谢途径。这里,中国五种典型的森林土壤,即黑土(哈尔滨,黑龙江),深棕色地球(长白山,吉林),黄褐土(武汉,湖北),红土(福州,福建),和湿热铁氧体土壤(乐东,海南),利用宏基因组技术结合基于性状的方法研究氮代谢途径的性状。研究的氮代谢途径是氨同化,硝酸盐异化还原,硝酸盐同化还原,反硝化,硝化,固氮,和厌氧氨氧化。结果表明,细菌在宏基因组文库中占主导地位,占全部序列的98.02%。在所有域中,最常见的途径是氨同化。例如,平均每百万个带注释的细菌序列检测到2830个氨同化途径基因。相比之下,固氮和厌氧氨氧化是检测到最少的途径,占每百万序列28.3和10.7,分别。不同的微生物可以参与相同的氮代谢途径,不同土壤的群落结构是可变的。中国五种典型的森林土壤表现出相同的微生物氮代谢途径性状;然而,发现介导这些过程的微生物的群落结构各不相同。
Nitrogen metabolism pathways mediated by microorganisms play an important role in maintaining the structure and functional stability of soil ecosystems. Clarifying the relationships between microbial communities and nitrogen metabolism pathways can expand our understanding of nitrogen metabolism pathways at a microscopic level. However, the horizontal gene transfer of microorganisms means that taxonomy-based methods cannot be easily applied. A growing number of studies have shown that functional traits affect community construction and ecosystem functions. Using methods based on functional traits to study soil microbial communities can, therefore, better characterize nitrogen metabolism pathways. Here, five typical forest soils in China, namely black soil(Harbin, Heilongjiang), dark-brown earth(Changbaishan, Jilin), yellow-brown earth(Wuhan, Hubei), red earth(Fuzhou, Fujian), and humid-thermo ferralitic soil(Ledong, Hainan), were selected to study the traits of nitrogen metabolism pathways using metagenomic technology combined with the trait-based methods. The studied nitrogen metabolism pathways were ammonia assimilation, nitrate dissimilatory reduction, nitrate assimilatory reduction, denitrification, nitrification, nitrogen fixation, and anaerobic ammonia oxidation. The results showed that bacteria dominated the metagenomic library, accounting for 98.02% of all the sequences. Across all domains, the most common pathway was ammonia assimilation. For example, an average of 2830 ammonia assimilation pathway genes were detected for every million annotated bacterial sequences. In comparison, nitrogen fixation and anaerobic ammonia oxidation were the least detected pathways, accounting for 28.3 and 10.7 per million sequences, respectively. Different microorganisms can participate in a same nitrogen metabolism pathway, and the community structure of different soils was variable. The five typical forest soils in China show the same microbial nitrogen metabolism pathway traits; however, the community structure of the microorganisms mediating these processes was found to vary.