Brevibacillus soli sp. nov., a Siderophore and IAA-Producing Strain Isolated from Soil

A Gram-stain-positive bacterium capable of producing siderophore and indole-3-acetic acid (IAA), designated strain H7^T, was isolated from soil of grassland in Nanchang, Jiangxi Province. Cells were rod-shaped, facultatively anaerobic, endospore-forming and motile by peritrichous flagella. Cells grow at 15-42 °C (optimum, 30 °C), pH 5-9 (optimum, pH 7) and with 0-10% NaCl (w/v; optimum, 2%). 16S rRNA gene sequence analysis showed that strain H7^T belonged to the genus Brevibacillus and was most related to B. brevis NBRC 15304^T (96.7%), B. fortis NRRL NRS-1210^T (96.7%), B. formosus DSM 9885^T (96.6%), and B. porteri NRRL B-41110^T (96.6%). Phylogenetic tree based on genome and 16S rRNA gene sequences indicated that strain H7^T was clustered in the genus Brevibacillus but formed a separate clade. The genome size of H7^T was 4.05 Mb. The nucleotide identity (ANI) value and digital DNA-DNA hybridization (dDDH) between the genomes of strain H7^T and the closely related type strains ranged from 71.2 to 73.1% and 14.9-20.5%, respectively. The major cellular fatty acids (≥ 5%) are anteiso-C_15:0, iso-C_16:0, C_16:1ω7calcohol, iso-C_14:0 and iso-C_15:0. The major polar lipids were phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylmonomethylethanolamine (PME) and one unidentified lipid (UL). The predominant respiratory quinone was MK-7. The DNA G + C content was 52.1%. Based on phylogenetic, genomic, chemotaxonomic and phenotypic data, strain H7^T (= MCCC 1K09426^T= KCTC 43803^T) was considered to represent a novel species of genus Brevibacillus which the name Brevibacillus soli sp. nov. is proposed.