The global nitrogen cycle is of paramount significance as it affects important processes like primary productivity and decomposition. Nitrification, the oxidation of ammonia to nitrate via nitrite, is a key process in the nitrogen cycle. The knowledge about nitrification has been challenged during the last few decades with inventions like anaerobic ammonia oxidation, ammonia-oxidizing archaea, and recently the complete ammonia oxidation (comammox). The discovery of comammox Nitrospira has made a paradigm shift in nitrification, before which it was considered as a two-step process, mediated by chemolithoautotrophic ammonia oxidizers and nitrite oxidizers. The genome of comammox Nitrospira equipped with molecular machineries for both ammonia and nitrite oxidation. The genus Nitrospira is ubiquitous, comes under phylum Nitrospirae, which comprises six sublineages consisting of canonical nitrite oxidizers and comammox. The single-step nitrification is energetically more feasible; furthermore, the existence of diverse metabolic pathways in Nitrospira is critical for its establishment in various habitats. The present review discusses the taxonomy, ecophysiology, isolation, identification, growth, and metabolic diversity of the genus Nitrospira; compares the genomes of canonical nitrite-oxidizing Nitrospira and comammox Nitrospira, and analyses the differences of Nitrospira with other nitrifying bacteria.

中文翻译：

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Nitrospira 作为多功能硝化菌：分类学、生态生理学、基因组特征、生长和代谢多样性

全球氮循环至关重要，因为它影响初级生产力和分解等重要过程。硝化作用是氨通过亚硝酸盐氧化成硝酸盐，是氮循环中的关键过程。在过去的几十年中，随着厌氧氨氧化、氨氧化古细菌和最近的完全氨氧化 (comammox) 等发明，有关硝化作用的知识受到挑战。comammox Nitrospira 的发现使硝化作用发生了范式转变，在此之前，它被认为是由化学自养氨氧化剂和亚硝酸盐氧化剂介导的两步过程。comammox Nitrospira 的基因组配备了用于氨和亚硝酸盐氧化的分子机制。Nitrospira 属普遍存在，属于 Nitrospirae 门，它包括六个亚系，由典型的亚硝酸盐氧化剂和 comammox 组成。一步硝化在能量上更可行；此外，Nitrospira 中多种代谢途径的存在对其在各种栖息地中的建立至关重要。本综述讨论了 Nitrospira 属的分类学、生态生理学、分离、鉴定、生长和代谢多样性；比较了典型的亚硝酸盐氧化硝化螺菌和 comammox Nitrospira 的基因组，并分析了 Nitrospira 与其他硝化细菌的差异。本综述讨论了 Nitrospira 属的分类学、生态生理学、分离、鉴定、生长和代谢多样性；比较了典型的亚硝酸盐氧化硝化螺菌和 comammox Nitrospira 的基因组，并分析了 Nitrospira 与其他硝化细菌的差异。本综述讨论了 Nitrospira 属的分类学、生态生理学、分离、鉴定、生长和代谢多样性；比较了典型的亚硝酸盐氧化硝化螺菌和 comammox Nitrospira 的基因组，并分析了 Nitrospira 与其他硝化细菌的差异。