Microbulbifer rhizosphaerae sp. nov., isolated from the rhizosphere of the halophyte Arthrocnemum macrostachyum.

A novel, salt-dependent, non-motile, rod-shaped, Gram-stain-negative and non-endospore-forming bacterium, designated strain Cs16bT, was isolated from the rhizosphere of Arthrocnemum macrostachyum, a halophytic plant at the Lebrija marshes (Seville, Spain). Strain Cs16bT was catalase- and oxidase-positive, and able to hydrolyse casein. Growth occurred from 15-40 °C, at pH 6.0-10.0 and with 1-6% (w/v) NaCl. Q-8 was identified as the major ubiquinone and the predominant cellular fatty acids were iso-C15:0, iso-C17:1cis8, iso-C11:0 3-OH, iso-C17:0, C17:0 cyclo and iso-C11:0. The polar lipids profile consisted of phosphatidylethanolamine, phosphatidylglycerol, two unknown glycophospholipids, an unknown aminoglycophospholipid, an unknown aminophospholipid and an unknown phospholipid. The 16S rRNA gene of strain Cs16bT showed 98.1%, 97.8%, and 97.6% sequence similarity with Microbulbifer maritimus CIP 108504T, Microbulbifer taiwanensis DSM 24146T and Microbulbifer gwangyangensis JCM 17800T, respectively. Based on the phenotypic and genotypic features, it is concluded that strain Cs16bT represents a novel species of the genus Microbulbifer, for which the name Microbulbifer rhizosphaerae sp. nov. is proposed. The type strain is Cs16bT (=DSM 28920T=CECT 8799T).