Orders Oceanospirillales and Pseudomonadales play important roles in various ecosystems as the keystone taxa of microbiomes. However, the two orders present a close evolutionary relationship, which might have caused taxonomic misinterpretation and resulted in an incorrect understanding of their evolutionary history. In this study, first, we used the 16S rRNA gene sequences of 2,049 species of Gammaproteobacteria to build a phylogenetic tree, which demonstrated that reports regarding the evolutionary relationship of orders Cellvibrionales, Oceanospirillales, and Pseudomonadales based on a single conserved gene with a poor resolution have been conflicting; in particular, the major families Moraxellaceae and Pseudomonadaceae of order Pseudomonadales were separated from orders Cellvibrionales and Oceanospirillales. Subsequently, we constructed the bac120 trees of all representative reference genomes of class Gammaproteobacteria based on 120 ubiquitous single-copy proteins from bacteria and a phylogenomic tree based on the 119 core genes of 257 reference genomes obtained from orders Cellvibrionales, Oceanospirillales, and Pseudomonadales to cross validate and infer their intrinsic evolutionary relationships. These results indicated that two novel orders, Moraxellales ord. nov. and Kangiellales ord. nov., and three novel families, Marinobacteraceae fam. nov., Perlucidibacaceae fam. nov., and Zooshikellaceae fam. nov., should be proposed. Additionally, orders Cellvibrionales and Oceanospirillales were merged into the order Pseudomonadales except for families Moraxellaceae and Kangiellaceae in class Gammaproteobacteria, which currently includes 18 families. Our work sheds some light on the evolutionary history of class Gammaproteobacteria, which could facilitate the detection and taxonomic analysis of natural communities.

中文翻译：

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通过系统进化树分析，对丙型杆菌属中的细胞弧菌，海洋螺菌，假单胞菌和另类梭菌的分类框架进行了重新分类。

订单海洋螺菌和假单胞菌在微生物群落的重要分类群中，在各种生态系统中起着重要的作用。但是，这两个顺序具有密切的进化关系，这可能导致分类学上的误解并导致对它们的进化历史的错误理解。在这项研究中，首先，我们使用了2049种γ-变形杆菌的16S rRNA基因序列来构建系统发育树，这表明有关细胞单胞菌，大洋螺旋藻和假单胞菌的进化关系的报道。基于一个分辨率较差的保守基因的研究一直存在矛盾；特别是，主要的家庭Moraxellaceae和假单胞菌秩序假单胞菌从订单分离Cellvibrionales和海洋螺菌。随后，我们构建了类的所有代表性的参考基因组的bac120树木γ-变形菌基于来自细菌120无处不在单拷贝的蛋白质和基于从订单获得的257个参照基因组的119个基因芯一个phylogenomic树Cellvibrionales，海洋螺菌和假单胞菌交叉验证并推断其内在的进化关系。这些结果表明，两个新颖的订单，莫拉氏菌。十一月 和Kangiellales ord。十一月，以及三个新的家族，Marinobacteraceae fam。十一月，Perlucidibacaceae fam。十一月，和Zooshikellaceae家族。十一月，应提出。此外，除丙型杆菌属类的莫拉氏菌科和剑兰科以外，细胞弧菌和海洋螺菌纲被合并为假单胞菌纲。，目前包括18个家庭。我们的工作为伽玛变形杆菌类的进化历史提供了一些启示，可促进自然群落的发现和分类学分析。