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

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-79(T) 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 C 15:0 anteiso, C 15:0 iso and C 16:0, 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-79(T) 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-79(T) genome assembly and those of the closest relative Bacillaceae type strains were <71, <71and <25%, respectively. Physiological and biochemical test results were also different from those of the most closely related Bacillaceae species. As a consequence, JJ-79(T) represents a novel genus for which we propose the name Pseudoneobacillus rhizosphaerae gen. nov., sp. nov., with JJ-79(T) (=CIP 111885(T)=CCM 9045(T)) as the type strain.

Automated summary

A novel bacterium belonging to the genus Pseudoneobacillus was isolated from the rhizosphere of maize roots, showing similarities to Neobacillus species but with distinct differences. Therefore, we propose the name Pseudoneobacillus rhizosphaerae gen. nov., sp. nov.