Members of the genus Acidithiobacillus, now ranked within the class Acidithiobacillia, are model bacteria for the study of chemolithotrophic energy conversion under extreme conditions. Knowledge of the genomic and taxonomic diversity of Acidithiobacillia is still limited. Here, we present a systematic analysis of nearly 100 genomes from the class sampled from a wide range of habitats. Some of these genomes are new and others have been reclassified on the basis of advanced genomic analysis, thus defining 19 Acidithiobacillia lineages ranking at different taxonomic levels. This work provides the most comprehensive classification and pangenomic analysis of this deep-branching class of Proteobacteria to date. The phylogenomic framework obtained illuminates not only the evolutionary past of this lineage, but also the molecular evolution of relevant aerobic respiratory proteins, namely the cytochrome bo₃ ubiquinol oxidases.

Acidithiobacillus属的成员现在属于Acidithiobacillia类，是研究极端条件下化学无机营养能量转换的模型细菌。对酸性硫杆菌的基因组和分类学多样性的了解仍然有限。在这里，我们对从广泛栖息地采样的近 100 个基因组进行了系统分析。其中一些基因组是新的，其他基因组已根据高级基因组分析重新分类，从而定义了 19 种酸性硫杆菌谱系在不同分类水平上的排名。这项工作提供了迄今为止对变形杆菌的这种深分支类的最全面的分类和泛基因组分析。获得的系统发育框架不仅阐明了该谱系的进化历史，而且阐明了相关有氧呼吸蛋白（即细胞色素bo ₃泛醇氧化酶）的分子进化。