Thalassospira indica sp nov., isolated from deep seawater

A taxonomic study using a polyphasic approach was carried out on strain PB8B(T), which was isolated from the deep water of the Indian Ocean. Cells of the bacterium were Gram-stain negative, oxidase- and catalase-positive, curved rods and motile. Growth was observed at salinities of 0-15% and at temperatures of 10-41 degrees C. The isolate could reduce nitrate to nitrite and degrade Tween 80, but not degrade gelatin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain PB8B(T) belonged to the genus Thalassospira, with the highest sequence similarity to the closely related type strain Thalassospira tepidiphila 1-1 B-T (99.7%), followed by Thalassospira profundimaris WP0211(T) (99.6%). Multilocus sequence analysis demonstrated low similarities of 94.1 and 93.7% between strain PB8B(T) and the two reference type strains. Digital DNA-DNA hybridization values between strain PB8B(T) and the two above-mentioned type strains were, respectively, 56.3 and 55.3%. The principal fatty acids of strain PB8B(T) were C-18:1 omega 6C/C-18:1 omega 7c, C-19:0 cyclo omega 8c and C-16:0. The G+C content of the chromosomal DNA was 54.9 mol%. The quinone was determined to be 0-10 (100%). Phosphatidylglycerol, phosphatidylethanolamine, and several unidentified phospholipids and lipids were present. Based on phenotypic and genotypic characteristics, strain PB8B(T) represents a novel species within the genus Thalassospira, for which the name Thalassospira indica sp. nov. is proposed. The type strain of the novel species is PB8B(T) (=MCCC 1A01103(T)=LMG 29620(T)).