Chloroflexales (Chloroflexi) are typical members of the anoxygenic photosynthesizing component of microbial mats and have mostly been characterized from communities associated to hot springs. Here, we report the assembly of five metagenome-assembled genomes of a novel lineage of Chloroflexales found in mesophilic lithifying microbial mats (microbialites) in Lake Alchichica (Mexico). Genomic and phylogenetic analyses revealed that the bins shared 92% of their genes, and these genes were nearly identical despite being assembled from samples collected along a depth gradient (1-15 m depth). We tentatively name this lineage Candidatus Lithoflexus mexicanus. Metabolic predictions based on the MAGs suggest that these chlorosome-lacking mixotrophs share features in central carbon metabolism, electron transport, as well as adaptations to life under oxic and anoxic conditions, with members of two related lineages, Chloroflexineae and Roseiflexineae. Contrasting with the other diverse microbialite community members, which display much lower genomic conservation along the depth gradient, Ca. L. mexicanus MAGs exhibit remarkable similarity. This might reflect a particular flexibility to acclimate to varying light conditions with depth or the capacity to occupy a very specific spatial ecological niche in microbialites from different depths. Alternatively, Ca. L. mexicanus may also have the ability to modulate its gene expression as a function of the local environmental conditions during diel cycles in microbialites along the depth gradient.

中文翻译：

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沿深度显示准克隆模式的新型微粉岩相关的光养绿屈菌谱系。

绿屈挠菌（Chloroflexi）（Chloroflexi）是微生物垫的厌氧性光合作用成分的典型成员，其主要特征是与温泉有关的群落。在这里，我们报道了在阿尔奇奇卡湖（墨西哥）的嗜温石蜡化微生物垫（微生物）中发现的一种新的绿屈挠谱系的五个元基因组组装基因组的组装。基因组和系统发育分析表明，这些垃圾箱共有92％的基因，尽管这些基因是从沿深度梯度（1-15 m深度）收集的样本组装而成的，但它们几乎相同。我们暂定将此血统命名为Candidatus墨西哥石楠。基于MAG的代谢预测表明，这些缺乏氯体的混合营养型具有两个相关谱系的叶绿素和Roseiflexineae，它们具有中央碳代谢，电子运输以及在有氧和无氧条件下对生命的适应性。与其他多样化的微辉石群落成员相反，后者沿深度梯度Ca显示出较低的基因组保守性。墨西哥乳杆菌MAGs显示出显着的相似性。这可能反映了适应深度不同的光照条件的特殊灵活性，或者可以适应来自不同深度的微辉石中非常特殊的空间生态位。或者，Ca。 墨西哥乳杆菌还可能具有能力，根据微环境中沿深度梯度进行的dibia循环，根据局部环境条件调节其基因表达。