A rod-shaped, non-endospore-forming and non-motile bacterium, strain DL-329T, was isolated from the above-ground part of a plant, Androsace koso-poljanskii Ovcz. (Primulaceae), at the the State Natural Reserve 'Belogorie', Russia. On the basis of 16S rRNA gene sequence comparisons, the strain clustered with members of the genus Rathayibacter, showing the highest sequence similarity to Rathayibacter tritici (98.89 %), Rathayibacter rathayi (98.82 %) and Rathayibacter festucae (98.82 %). The DNA hybridization experiments demonstrated that strain DL-329T represents a separate genomic species. The results of comparative studies of physiological and chemotaxonomic characteristics, including cell-wall sugar patterns, polar lipid profiles, and the matrix-assisted laser desorption/ionization time-of-flight mass spectra of bacterial cells, allowed clear differentiation of VKM Ac-2121T from the recognized Rathayibacter species at the phenotypic level. Based on the data obtained, a new species, Rathayibacter oskolensis sp. nov., is proposed, with DL-329T (=VKM Ac-2121T=LMG 22542T) as the type strain.
Keywords: Rathayibacter oskolensis; calciphyte plant; new species; taxonomy.