Pseudoneobacillus rhizosphaerae gen. nov., sp. nov., isolated from maize root rhizosphere

Abstract

A facultative anaerobic, Gram-stain-positive, endospore-forming bacterium, isolated from the rhizosphere of maize roots (Zea mays), was taxonomically studied. Based on 16S rRNA gene sequence similarity comparisons, strain JJ-79T clustered only loosely with Neobacillus species and showed the highest similarity to Neobacillus soli (97.9%). The 16S rRNA gene sequence similarities to the sequences of the type strains of other Neobacillus species were 97.5 % and below. Chemotaxonomic features supported the grouping of the strain to the Neobacillus group, e.g. the major fatty acids were C15 : 0 anteiso, C15 : 0 iso and C16 : 0, the polar lipid profile contained the major components diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid, the major quinone was menaquinone MK-7, and major compound in the polyamine pattern was spermidine. However, the JJ-79T genome assembly did not share most of the 11 conserved signature indels that are indicative of the genus Neobacillus . The average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values between the JJ-79T genome assembly and those of the closest relative Bacillaceae type strains were <71, <71 and <25 %, respectively. Physiological and biochemical test results were also different from those of the most closely related Bacillaceae species. As a consequence, JJ-79T represents a novel genus for which we propose the name Pseudoneobacillus rhizosphaerae gen. nov., sp. nov., with JJ-79T (=CIP 111885T=CCM 9045T) as the type strain.