Salinicoccus bachuensis sp. nov., a novel halophilic bacterium, isolated from rhizosphere soil surrounding Tamarix chinensis Lour. plants in Bachu County, Xinjiang, China.

The strain Bachu38 was isolated from the rhizosphere soil of Tamarix chinensis Lour. plants in Bachu County, Xinjiang, China. This strain exhibited growth under a wide range of conditions, with temperature tolerance from 8 to 45°C (optimal at 28°C), pH adaptability between 7.0 and 10.0 (optimal range 8.0-9.0), and NaCl concentration tolerance spanning 2-20% (w/v), with optimal growth observed at 8% NaCl concentration. The cells displayed a spherical morphology and were Gram-positive, non-motile, and devoid of flagella. Biochemical characterization demonstrated positive reactions for both oxidase and catalase activities. Phylogenetic analysis of the 16S rRNA gene sequences revealed that strain Bachu38 forms an independent branch within the genus Salinicoccus, sharing the highest sequence similarity with S. roseus DSM 5351 (98.43%) and S. amylolyticus JC304 (98.29%). The whole genome comprised 2.62 Mb, with a G + C content of 49.5%. When compared with the related strains, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were 71.34-90.99% and 17.20-42.40%, respectively, which were below the suggested species identification threshold (ANI: < 95-96%, dDDH: < 70%) for different prokaryotic species. The respiratory quinone was identified as MK-6, and the cell wall peptidoglycan type was -Lys-Gly. Fatty acid analysis demonstrated that the major cellular fatty acids were iso-C and anteiso-C, each accounting for more than 10% of the total fatty acid composition. The polar lipid profile consisted of phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), glycolipid (GL), along with two unidentified lipids (designated as UL1 and UL2). Based on polyphasic taxonomic approaches incorporating phenotypic, physiological, and biochemical characteristics, along with comprehensive phylogenetic and genomic analyses, strain Bachu38 is proposed to represent a novel species of the genus Salinicoccus, named Salinicoccus bachuensis sp. nov., with strain Bachu38 (= CGMCC NO.28832 = JCM 37304) designated as the type strain.