Marinobacter xestospongiae sp. nov., isolated from the marine sponge Xestospongia testudinaria collected from the Red Sea

Abstract

A Gram-negative, catalase- and oxidase-positive, non-sporulating, rod-shaped and slightly halophilic bacterial strain, designated UST090418-1611T, was isolated from the marine sponge Xestospongia testudinaria collected from the Red Sea coast of Saudi Arabia. Phylogenetic trees based on the 16S rRNA gene sequence placed strain UST090418-1611T in the family Alteromonadaceae with the closest relationship to the genus Marinobacter . The 16S rRNA gene sequence similarity between the strain and the type strains of recognized Marinobacter species ranged from 92.9 to 98.3 %. Although strain UST090418-1611T shared high 16S rRNA gene sequence similarity with Marinobacter mobilis CN46T, M. zhejiangensis CN74T and M. sediminum R65T (98.3, 97.4 and 97.3 %, respectively), the relatedness of the strain to these three strains in DNA–DNA hybridization was only 58, 56 and 33 %, respectively, supporting the novelty of the strain. In contrast to most strains in the genus Marinobacter , strain UST090418-1611T tolerated only 6 % (w/v) NaCl, and optimal growth occurred at 2.0 % (w/v) NaCl, pH 7.0–8.0 and 28–36 °C. The predominant cellular fatty acids were C12 : 0 3-OH, C16 : 0, C12 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The genomic DNA G+C content was 57.1 mol%. Based on the physiological, phylogenetic and chemotaxonomic characteristics presented in this study, we suggest that the strain represents a novel species in the genus Marinobacter , for which the name Marinobacter xestospongiae sp. nov. is proposed, with UST090418-1611T ( = JCM 17469T  = NRRL B-59512T) as the type strain.