Thalassospira marina sp nov., isolated from surface seawater

Two novel marine bacteria, designated strains CSC3H3T and CSC1P2, were isolated from surface seawater of the South China Sea. Both strains were Gram-negative, oxidase-positive, catalase-positive, curved rods and motile. They grew at 10-40 degrees C, pH 5-10 and in the presence of 0-15 % (w/v) NaCl. Their 16S rRNA gene sequences were identical to each other. Phylogenetic analysis based on 16S rRNA gene sequences indicated that they belong to the genus Thalassospira, and shared 97.5-98.3 % sequence similarity to all other validly type strains of the genus Thalassospira, and the highest similarity was to the type strain Thalassospira povalilytica Zumi 95T (98.3 %), followed by Thalassospira australica NP3b2T (98.2 %). The digital DNA-DNA hybridization value between the two strains was 80.4 %, while the values with T. povalilytica Zumi 95T and T. australica NP3b2T were only 20.5-20.7 % and 20.4-20.5 %, respectively. The two strains possess similar major cellular fatty acids including C-18:1.omega c, C-16 : 0, C(19 : 0.omega)8c cyclo, C-18 : 1 2-OH and C-17 : 0 cyclo. The G+C contents of the chromosomal DNA of strains CSC3H3T and CSC1P2 were 54.6 and 54.5 mol%, respectively. The major respiratory quinone was ubiquinone 10. Phosphatidylethanolamine, phosphatidylglycerol and several unidentified phospholipids, aminolipid and lipids were present in both strains. Based on phenotypic and genotypic characteristics, the two strains represent a novel species within the genus Thalassospira, for which the name Thalassospira marina sp. nov. is proposed. The type strain is CSC3H3(T) (=MCCC 1A11786(T)= KCTC 62333(T)).