Phylogenomics insights into order and families of .

Order (earlier known ) is a taxonomically complex group of a large number of gamma-proteobacteria classified in two different families, namely and . Current taxonomy is largely based on classical approaches and is devoid of whole-genome information-based analysis. In the present study, we have taken all classified and poorly described species belonging to the order to perform a phylogenetic analysis based on the 16 S rRNA sequence. Moreover, to obtain robust phylogeny, we have generated whole-genome sequencing data of six type species namely and of the families and . Interestingly, whole-genome-based phylogenetic analysis revealed unusual positioning of the type species , and at family level. Whole-genome-based phylogeny involving 92 type strains resolved the taxonomic positioning by reshuffling the genus across families and . The present study reveals the need and scope for genome-based phylogenetic and comparative studies in order to address relationships of genera and species of order .