Vibrio iocasae sp. nov., a bacterium isolated from the gill homogenate of bivalve lucinids Indoaustriella scarlatoi in intertidal mangrove sediments.

A novel Vibrio strain, HN007, was isolated from the gill homogenate of the bivalve lucinid Indoaustriella scarlatoi in intertidal mangrove sediments in Huiwen town, Hainan province, PR China. Cells of strain HN007 were Gram-stain-negative, facultatively anaerobic, motile, rod-shaped, and positive for oxidase and catalase activities. Growth occurred at 16-39 °C, at pH 6.0-11.0 and with 0-7% (w/v) NaCl. Molecular phylogenetic analysis based on 16S rRNA gene sequences affiliated the strain to the members of the genus Vibrio, with the closest species being Vibrio hannami 168GH5-2-16 (96.9% similarity), Vibrio variabilis R-40492 (96.1%), Vibrio aestivus M22 (95.8%), Vibrio maritimus R-40493 (95.4%), Vibrio mexicanus CAIM 1540 (95.4%), and Vibrio profundi TP187 (95.3%). The genome size of strain HN007 was 5,834,927 bp, with a DNA G + C content of 43.5%. The average nucleotide identity, digital DNA-DNA hybridisation, and average amino acid identity values between strain HN007 and the most related strains, were all below the thresholds typically used to define genomic species. Further genomic analysis clustered strain HN007 with the reference strain V. hannami LMG 30079 within the Albus clade. The major cellular fatty acids of strain HN007 were summed feature 3 (Cω6c and/or Cω7c, 40.9%) and summed feature 8 (C ω7c and/or C ω6c, 29.4%). The predominant polar lipid was phosphatidylethanolamine, while ubiquinone-8 was the predominant quinone. Based on genomic, chemotaxonomic, and physiological analysis, strain HN007 represents a novel species within the genus Vibrio, proposed to be named Vibrio iocasae sp. nov. The type strain is HN007 (= MCCC 1K08504 = KCTC 92899 = JCM 35938).