Characterization and Distribution of Agar-degrading Steroidobacter agaridevorans sp. nov., Isolated from Rhizosphere Soils

Steroidobacter gossypii sp. nov., isolated from cotton field soil

A Gram-negative bacterium, designated S1-65^T, was isolated from soil samples collected from a cotton field located in the Xinjiang region of PR China. Results of 16S rRNA gene sequence analysis revealed that strain S1-65^T was affiliated to the genus Steroidobacter with its closest phylogenetic relatives being 'Steroidobacter cummioxidans' 35Y (98.4 %), 'Steroidobacter agaridevorans' SA29-B (98.3 %) and Steroidobacter agariperforans KA5-B^T (98.3 %). 16S rRNA-directed phylogenetic analysis showed that strain S1-65^T formed a unique phylogenetic subclade next to 'S. agaridevorans' SA29-B and S. agariperforans KA5-B^T, suggesting that strain S1-65^T should be identified as a member of the genus Steroidobacter. Further, substantial differences between the genotypic properties of strain S1-65^T and the members of the genus Steroidobacter, including average nucleotide identity and digital DNA-DNA hybridization, resolved the taxonomic position of strain S1-65^T and suggested its positioning as representing a novel species of the genus Steroidobacter. The DNA G+C content of strain S1-65^T was 62.5 mol%, based on its draft genome sequence. The predominant respiratory quinone was ubiquinone-8. The main fatty acids were identified as summed feature 3 (C_16:1ω6c/C_16:1ω7c), C_16 : 0 and iso-C_15 : 0. In addition, its polar lipid profile was composed of aminophospholipid, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Here, we propose a novel species of the genus Steroidobacter: Steroidobacter gossypii sp. nov. with the type strain S1-65^T (=JCM 34287^T=CGMCC 1.18736^T).