潮滩湿地硝化螺菌的代谢潜力和环境适应机制

Metabolic potential and environmental adaptation mechanisms of Nitrospira in tidal flat wetlands

为了揭示硝化螺菌(Nitrospira)在潮滩湿地中的代谢潜力和环境适应机制,本研究使用宏基因组学拼接与组装的方法,从中国沿岸的5个潮滩湿地构建了14个较高质量的Nitrospira基因组.系统发育分析结果表明,在这些基因组中,3个属于全程氨氧化细菌(complete ammonia oxidizer,Comammox);9个为硝化螺菌世系Ⅱ和Ⅳ;2个属于至今未见报道的世系Ⅲ型.这表明,潮滩湿地富含多样化的硝化螺菌类群.代谢分析表明,潮滩湿地Comammox和典型的Nitrospira含有氰酸酶、脲酶以及参与腈类、酰胺类化合物分解的酶,暗示着它们能够与氨氧化微生物耦合利用有机氮作为能源.此外,Nitrospira有着多重压力抵抗、病毒防御和渗透压调控策略.这些结果深化了对Nitrospira在潮滩湿地的多样性、生态功能潜力和环境适应机制上的认识.

To understand the metabolic potential and environmental adaptation mechanisms of Nitrospira in tidal flat wetlands,14 high-quality Nitrospira genomes were constructed from five tidal flat wetlands along the coast of China using metagenomic binning and assembly methods.Phylogenetic analysis showed that among these genomes,three belonged to Comammox(complete ammonia oxidizer),nine belonged to lineage II and IV of Nitrospira,and two belonged to lineage III,which has yet to be discovered;taken together,this data suggests that abundant and diverse Nitrospira are present in China’s tidal flat wetlands.Metabolic reconstruction revealed that these Comammox and Nitrospira contained cyanase,urease,and other enzymes involved in the degradation of nitrile compounds and amide compounds;hence,they may utilize the organic nitrogen as energy by coupling with ammonia-oxidizing microorganisms.In addition,Nitrospira possessed flexible strategies to resist environmental stresses such as viral attack and osmotic changes.These results provide insights on the diversity,ecological function,and environmental adaptation mechanisms of Nitrospira from tidal wetlands.