The metabolic capacity, stress response and evolution of uncultured environmental Tenericutes have remained elusive, since previous studies have been largely focused on pathogenic species. In this study, we expanded analyses on Tenericutes lineages that inhabit various environments using a collection of 840 genomes. Several environmental lineages were discovered inhabiting the human gut, ground water, bioreactors and hypersaline lake and spanning the Haloplasmatales and Mycoplasmatales orders. A phylogenomics analysis of Bacilli and Tenericutes genomes revealed that some uncultured Tenericutes are affiliated with novel clades in Bacilli, such as RF39, RFN20 and ML615. Erysipelotrichales and two major gut lineages, RF39 and RFN20, were found to be neighboring clades of Mycoplasmatales. We detected habitat-specific functional patterns between the pathogenic, gut and the environmental Tenericutes, where genes involved in carbohydrate storage, carbon fixation, mutation repair, environmental response and amino acid cleavage are overrepresented in the genomes of environmental lineages, perhaps as a result of environmental adaptation. We hypothesize that the two major gut lineages, namely RF39 and RFN20, are probably acetate and hydrogen producers. Furthermore, deteriorating capacity of bactoprenol synthesis for cell wall peptidoglycan precursors secretion is a potential adaptive strategy employed by these lineages in response to the gut environment. This study uncovers the characteristic functions of environmental Tenericutes and their relationships with Bacilli, which sheds new light onto the pathogenicity and evolutionary processes of Mycoplasmatales.

中文翻译：

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扩展未培养的环境球虫的系统生物学提供了对其致病性和与芽孢杆菌的进化关系的见解。

由于以前的研究主要集中在致病物种上，因此未培养的环境球虫的代谢能力，应激反应和进化仍然难以捉摸。在这项研究中，我们使用840个基因组进行了扩展，研究了在各种环境中栖息的Tenericutes谱系的分析。在人类肠道，地下水，生物反应器和高盐湖中发现了数个环境世系，并跨越了盐藻和支原体。芽孢杆菌和Tenericutes基因组的系统组学分析表明，一些未培养的Tenericutes与芽孢杆菌中的新进化枝相关，例如RF39，RFN20和ML615。发现Erysipelotrichales和两个主要肠道谱系RF39和RFN20是支原体的近枝。我们检测到了致病性，肠道和环境Tenericutes之间特定于栖息地的功能模式，其中涉及碳水化合物存储，碳固定，突变修复，环境响应和氨基酸裂解的基因在环境谱系的基因组中过分代表。环境适应。我们假设两个主要的肠道谱系，即RF39和RFN20，可能是乙酸盐和氢气的产生者。此外，细菌红素合成对于细胞壁肽聚糖前体分泌的能力下降是这些谱系响应于肠道环境而采用的潜在适应策略。这项研究揭示了环境Tenericutes的特征功能及其与芽孢杆菌的关系，