Comparative Genomic Analysis of Vibrio diabolicus and Six Taxonomic Synonyms: A First Look at the Distribution and Diversity of the Expanded Species

is a diverse genus of Gammaproteobacteria autochthonous to marine environments worldwide. and were originally isolated from deep-sea hydrothermal fields in the East Pacific Rise. These species are closely related to members of the Harveyi clade (e.g., and ) that are commonly isolated from coastal systems. This study reports the discovery and draft genome sequence of a novel isolate ( sp. 939) cultured from Pacific oysters ( ). Questions surrounding the identity of sp. 939 motivated a genome-scale taxonomic analysis of the Harveyi clade. A 49-genome phylogeny based on 1,109 conserved coding sequences and a comparison of average nucleotide identity (ANI) values revealed a clear case of synonymy between sp. 939, Art-Gut C1 and CNCM I-1629, EX25 and four strains (E0666, FF273, TS13, and V2). This discovery expands the species and makes available six additional genomes for comparative genomic analyses. The distribution of the expanded species is thought to be global given the range of isolation sources (horse mackerel, seawater, sediment, dentex, oyster, artemia and polycheate) and origins (China, India, Greece, United States, East Pacific Rise, and Chile). A subsequent comparative genomic analysis of this new eight-genome subclade revealed a high degree of individual genome plasticity and a large repertoire of genes related to virulence and defense. These findings represent a significant revision to the understanding of and as both have long been regarded as distinct species. This first look at the expanded subclade suggests that the distribution and diversity of this species mirrors that of other Harveyi clade species, which are notable for their ubiquity and diversity.