Marinobacter azerbaijanicus sp. nov., a moderately halophilic bacterium from Urmia Lake, Iran.

Abstract

A novel moderately halophilic, Gram-stain-negative and facultatively anaerobic bacterium, designated as strain TBZ242T, was isolated from water of Urmia Lake in the Azerbaijan region of Iran. The cells were found to be rod-shaped and motile by a single polar flagellum, producing circular and yellowish colonies. The strain could grow in the presence of 0.5-10 % (w/v) NaCl (optimum, 2.5-5 %). The temperature and pH ranges for growth were 15-45 °C (optimum 30 °C) and pH 7.0-11.0 (optimum pH 8.0) on marine agar. The 16S rRNA gene sequence analysis revealed that strain TBZ242T belonged to the genus Marinobacter, showing the highest similarities to Marinobacter algicola DG893T (98.8 %), Marinobacter vulgaris F01T (98.8 %), Marinobacter salarius R9SW1T (98.5 %), Marinobacter panjinensis PJ-16T (98.4 %), Marinobacter orientalis W62T (98.0 %) and Marinobacter denitrificans JB2H27T (98.0 %). The 16S rRNA and core-genome phylogenetic trees showed that strain TBZ242T formed a distinct branch, closely related to a subclade accommodating M. vulgaris, M. orientalis, M. panjinensis, M. denitrificans, M. algicola, M. salarius and M. iranensis, within the genus Marinobacter. Average nucleotide identity and digital DNA-DNA hybridization values between strain TBZ242T and the type strains of the related species of Marinobacter were ≤85.0 and 28.6 %, respectively, confirming that strain TBZ242T represents a distinct species. The major cellular fatty acids of strain TBZ242T were C16 : 0 and C16 : 1  ω7c/C16 : 1 ω6c and the quinone was ubiquinone Q-9. The genomic DNA G+C content of strain TBZ242T is 57.2 mol%. Based on phenotypic, chemotaxonomic and genomic data, strain TBZ242T represents a novel species within the genus Marinobacter, for which the name Marinobacter azerbaijanicus sp. nov. is proposed. The type strain is TBZ242T (= CECT 30649T = IBRC-M 11466T). Genomic fragment recruitment analysis showed that this species prefers aquatic saline environments with intermediate salinities, being detected on metagenomic databases of Lake Meyghan (Iran) with 5 and 18 % salinity, respectively.