Recent discoveries of mcr and mcr‐like genes in genomes from diverse archaeal lineages suggest that methane metabolism is an ancient pathway with a complicated evolutionary history. One conventional view is that methanogenesis is an ancestral metabolism of the class Thermoplasmata. Through comparative genomic analysis of 12 Thermoplasmata metagenome‐assembled genomes (MAGs) basal to the Methanomassiliicoccales, we show that these microorganisms do not encode the genes required for methanogenesis. Further analysis of 770 Ca. Thermoplasmatota genomes/MAGs found no evidence of mcrA homologues outside of the Methanomassiliicoccales. Together, these results suggest that methanogenesis was laterally acquired by an ancestor of the Methanomassiliicoccales. The 12 analysed MAGs include representatives from four orders basal to the Methanomassiliicoccales, including a high‐quality MAG that likely represents a new order, Ca. Lunaplasma lacustris ord. nov. sp. nov. These MAGs are predicted to use diverse energy conservation pathways, including heterotrophy, sulfur and hydrogen metabolism, denitrification, and fermentation. Two lineages are widespread among anoxic, sedimentary environments, whereas Ca. Lunaplasma lacustris has thus far only been detected in alpine caves and subarctic lake sediments. These findings advance our understanding of the metabolic potential, ecology, and global distribution of the Thermoplasmata and provide insight into the evolutionary history of methanogenesis within the Ca. Thermoplasmatota.

中文翻译：

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甲烷气单胞菌基础的全球分布古细菌进化枝中非甲烷生成代谢的证据

来自不同古细菌谱系的基因组中的mcr和mcr样基因的最新发现表明，甲烷代谢是一条具有复杂进化史的古老途径。一种传统的观点是，产甲烷作用是Thermoplasmata类的祖先代谢。通过12的比较基因组分析Thermoplasmata宏基因组组装的基因组（MAG的）基于Methanomassiliicoccales，我们表明，这些微生物不编码用于所需甲烷的基因。770 Ca的进一步分析。Thermoplasmatota基因组/ MAG的没有发现任何证据MCRA同系物外的Methanomassiliicoccales。总之，这些结果表明，甲烷是横向地的祖先获得Methanomassiliicoccales。12点分析的MAG包括四个数量级的代表基肥到Methanomassiliicoccales，包括高品质的MAG这可能代表一个新的秩序，钙。月光草。十一月 sp。十一月 预计这些MAG将使用多种节能途径，包括异养，硫和氢代谢，反硝化和发酵。在缺氧，沉积环境中有两个谱系分布广泛，而Ca。迄今为止，仅在高山洞穴和北极湖底沉积物中发现了月球藻。这些发现提高了我们对嗜热亚种的代谢潜力，生态学和全球分布的理解，并提供了对Ca内甲烷生成的进化历史的认识。嗜热菌。