Gracilibacillus salitolerans sp. nov., a moderate halophile isolated from saline soil in Northwest China

A moderately halophilic strain, designated SCU50^T, was recovered from a saline soil sample and characterized by a polyphasic approach. The 16S rRNA gene sequence analysis showed that strain SCU50^T belonged to the genus Gracilibacillus and was most closely related to Gracilibacillus thailandensis TP2-8^T (98.1 % similarity) and Gracilibacillus orientalis XH-63^T (97.7 %). Genomic average nucleotide identity and digital DNA-DNA hybridization analyses confirmed the separate species status of the new isolate relative to other recognized Gracilibacillus species. The genome size was about 5.09 Mbp and the DNA G+C content was 36.7 mol%. The strain grew optimally at 10-15 % (w/v) NaCl, pH 6.5-7.5 and 25-30 °C. It contained anteiso-C_15 : 0, iso-C_15 : 0 and anteiso-C_17 : 0 as the dominant fatty acids and menaquinone-7 as the major respiratory quinone. The polar lipid profile was examined and found to comprise diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid and one unidentified lipid. The cell-wall peptidoglycan type was A1γ based on meso-diaminopimelic acid. Combining the data from phenotypic, chemotaxonomic, genomic and phylogenetic characterization, it was concluded that strain SCU50^T should be assigned as representing a novel species within the genus Gracilibacillus. Thus, a novel taxon named Gracilibacillus salitolerans sp. nov. was first established, with SCU50^T (=CGMCC 1.17336^T=KCTC 43107^T) as the type strain.