A comprehensive genomic analysis provides insights on the high environmental adaptability of strains.

is ubiquitous, and it has a high species diversity and a complex evolutionary pattern. To elucidate the mechanism of its high ability to adapt to various environment, 312 genomes of strains were analyzed using the phylogenomic and comparative genomics methods. It was revealed that the genus has an open pan-genome and strong genome plasticity. The pan-genome consists of 47,500 genes, with 818 shared by all the genomes of , while 22,291 are unique genes. Although strains do not have a complete glycolytic pathway to directly utilize glucose as carbon source, most of them harbored the -alkane-degrading genes / (97.1% of tested strains) and (96.7% of tested strains), which were responsible for medium-and long-chain -alkane terminal oxidation reaction, respectively. Most strains also have (93.3% of tested strains) and (92.0% of tested strains) genes that can degrade the aromatic compounds catechol and benzoic acid, respectively. These abilities enable the strains to easily obtain carbon and energy sources from their environment for survival. The strains can manage osmotic pressure by accumulating potassium and compatible solutes, including betaine, mannitol, trehalose, glutamic acid, and proline. They respond to oxidative stress by synthesizing superoxide dismutase, catalase, disulfide isomerase, and methionine sulfoxide reductase that repair the damage caused by reactive oxygen species. In addition, most strains contain many efflux pump genes and resistance genes to manage antibiotic stress and can synthesize a variety of secondary metabolites, including arylpolyene, β-lactone and siderophores among others, to adapt to their environment. These genes enable strains to survive extreme stresses. The genome of each strain contained different numbers of prophages (0-12) and genomic islands (GIs) (6-70), and genes related to antibiotic resistance were found in the GIs. The phylogenetic analysis revealed that the and genes have a similar evolutionary position with the core genome, indicating that they may have been acquired by vertical gene transfer from their ancestor, while , , and the antibiotic resistance genes could have been acquired by horizontal gene transfer from the other organisms.