Candidatus phylum Eremiobacterota (formerly WPS-2) is an as-yet-uncultured bacterial clade that takes its name from Ca. Eremiobacter, an Antarctic soil aerobe proposed to be capable of a novel form of chemolithoautotrophy termed atmospheric chemosynthesis, that uses the energy derived from atmospheric H₂-oxidation to fix CO₂ through the Calvin-Benson-Bassham (CBB) cycle via type 1E RuBisCO. To elucidate the phylogenetic affiliation and metabolic capacities of Ca. Eremiobacterota, we analysed 63 public metagenome-assembled genomes (MAGs) and nine new MAGs generated from Antarctic soil metagenomes. These MAGs represent both recognized classes within Ca. Eremiobacterota, namely Ca. Eremiobacteria and UBP9. Ca. Eremiobacteria are inferred to be facultatively acidophilic with a preference for peptides and amino acids as nutrient sources. Epifluorescence microscopy revealed Ca. Eremiobacteria cells from Antarctica desert soil to be coccoid in shape. Two orders are recognized within class Ca. Eremiobacteria: Ca. Eremiobacterales and Ca. Baltobacterales. The latter are metabolically versatile, with individual members having genes required for trace gas driven autotrophy, anoxygenic photosynthesis, CO oxidation, and anaerobic respiration. UBP9, here renamed Ca. Xenobia class. nov., are inferred to be obligate heterotrophs with acidophilic adaptations, but individual members having highly divergent metabolic capacities compared to Ca. Eremiobacteria, especially with regard to respiration and central carbon metabolism. We conclude Ca. Eremiobacterota to be an ecologically versatile phylum with the potential to thrive under an array of “extreme” environmental conditions.

Candidatus phylum Eremiobacterota（以前称为 WPS-2）是一种尚未培养的细菌进化枝，其名称来源于Ca。Eremiobacter，一种南极土壤好氧菌，被认为能够进行一种称为大气化学合成的新型化能自养，它使用来自大气 H ₂ -氧化的能量通过 Calvin-Benson-Bassham (CBB) 循环通过 1E RuBisCO固定 CO ₂ . 阐明Ca的系统发育关系和代谢能力。Eremiobacterota，我们分析了 63 个公共宏基因组组装基因组 (MAG) 和 9 个从南极土壤宏基因组产生的新 MAG。这些 MAG 代表Ca中的两个公认类别。Eremiobacterota，即Ca. Eremiobacteria 和 UBP9。钙。据推测，Eremiobacteria 是兼性嗜酸菌，偏爱肽和氨基酸作为营养来源。落射荧光显微镜显示Ca。来自南极洲沙漠土壤的 Eremiobacteria 细胞呈球形。在Ca类中识别两个订单。电弧菌：Ca。Eremiobacterales 和Ca。巴尔托细菌。后者在代谢上具有多样性，个体成员具有微量气体驱动的自养、缺氧光合作用、CO 氧化和厌氧呼吸所需的基因。UBP9，这里更名为Ca。异诺比亚级。十一月., 被推断为具有嗜酸适应性的专性异养生物，但与Ca相比，个体成员具有高度不同的代谢能力。Eremiobacteria，特别是在呼吸和中心碳代谢方面。我们得出结论Ca。Eremiobacterota 是一种生态多功能门，具有在一系列“极端”环境条件下茁壮成长的潜力。