Neobacillus rhizosphaerae sp. nov., isolated from the rhizosphere, and reclassification of Bacillus dielmonensis as Neobacillus dielmonensis comb. nov.

Lien vers Pubmed [PMID] – 36327328

Lien DOI – 10.1099/ijsem.0.005636

Int J Syst Evol Microbiol 2022 Nov; 72(11):

A Gram-stain-positive, facultative anaerobic endospore-forming bacterium, which originated from roots/rhizosphere of maize (Zea mays), was investigated for its taxonomic position. On the basis of 16S rRNA gene sequence similarities, strain JJ-3^T was grouped together with Neobacillus species showing the highest similarities to Neobacillus bataviensis (98.8%) and the three species Neobacillus dendrensis, Neobacillus soli and Neobacillus cucumis (all 98.6%). The 16S rRNA gene sequence similarities to the sequences of the type strains of other Neobacillus species were lower than 98.5 %. The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between the JJ-3^T genome assembly and those of the other Neobacillus type strains were <83, <85  and <27%, respectively. Chemotaxonomic features supported the grouping of the strain to the genus Neobacillus, e.g. the major fatty acids were C15:0 anteiso and C15:0 iso, the polar lipid profile contained the major components diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine, and the major quinone was menaquinone MK-7. Physiological and biochemical test results were slightly different from those of the most closely related species. For this reason, JJ-3^T represents a novel species of the genus Neobacillus, for which we propose the name Neobacillus rhizosphaerae sp. nov., with JJ-3^T (= CIP 111895^T = LMG 32087^T = DSM 111784^T = CCM 9084^T) as the type strain. We also propose to reclassify Bacillus dielmonensis as Neobacillus dielmonensis comb. nov. based mainly on the results of phylogenomic and conserved signature indel analyses.