Halomonas maris sp. nov., a moderately halophilic bacterium isolated from sediment in the southwest Indian Ocean

Abstract

A halophilic, Gram-staining-negative, rod-shaped, flagellated and motile bacterium, strain QX-1T, was isolated from deep-sea sediment at a depth of 3332m in the southwestern Indian Ocean. Strain QX-1T growth was observed at 4-50°C (optimum 37°C), pH 5.0-11.0 (optimum pH 7.0), 3-25% NaCl (w/v; optimum 7%), and it did not grow without NaCl. A phylogenetic analysis based on the 16S rRNA gene placed strain QX-1T in the genus Halomonas and most closely related to Halomonas sulfidaeris (97.9%), Halomonas zhaodongensis (97.8%), Halomonas songnenensis (97.6%), Halomonas hydrothermalis (97.4%), Halomonas subterranea (97.3%), Halomonas salicampi (97.1%), and Halomonas arcis (97.0%). DNA-DNA hybridization (< 26.5%) and average nucleotide identity values (< 83.5%) between strain QX-1T and the related type strains meet the accepted criteria for a new species. The principal fatty acids (> 10%) of strain QX-1T are C16:0 (25.5%), C17:0 cyclo (14.0%), C19:0 cyclo ω8c (18.7%), and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c, 18.1%). The polar lipids of strain QX-1T are mainly diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid, unidentified aminophospholipid, and five unidentified lipids. The main respiratory quinone is Q-9. The G + C content of its chromosomal DNA is 54.4mol%. Its fatty acid profile, respiratory quinones, and G + C content also support the placement of QX-1T in the genus Halomonas. These phylogenetic, phenotypic, and chemotaxonomic analyses indicate that QX-1T is a novel species, for which the name Halomonas maris is proposed. The type strain is QX-1T (= MCCC 1A17875T = KCTC 82198T = NBRC 114670T).