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^T, 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^T 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^T (96.9% similarity), Vibrio variabilis R-40492^T (96.1%), Vibrio aestivus M22^T (95.8%), Vibrio maritimus R-40493^T (95.4%), Vibrio mexicanus CAIM 1540^T (95.4%), and Vibrio profundi TP187^T (95.3%). The genome size of strain HN007^T 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^T and the most related strains, were all below the thresholds typically used to define genomic species. Further genomic analysis clustered strain HN007^T with the reference strain V. hannami LMG 30079^T within the Albus clade. The major cellular fatty acids of strain HN007^T were summed feature 3 (C_16:1ω6c and/or C_16:1ω7c, 40.9%) and summed feature 8 (C_18:1 ω7c and/or C_18:1 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^T represents a novel species within the genus Vibrio, proposed to be named Vibrio iocasae sp. nov. The type strain is HN007^T (= MCCC 1K08504^T = KCTC 92899^T = JCM 35938^T).