Rhodobacter johrii sp. nov., an endospore-producing cryptic species isolated from semi-arid tropical soils

Abstract

An oval to rod-shaped, phototrophic, purple non-sulfur bacterium, strain JA192T, was isolated from an enrichment culture of a pasteurized rhizosphere soil sample from a field cultivated with jowar (sorghum) collected from Godumakunta village near Hyderabad, India. Strain JA192T is Gram-negative, motile and produces endospores. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that the strain JA192T is closely related to Rhodobacter sphaeroides 2.4.1T (99.9% sequence similarity), Rba. megalophilus JA194T (99.8 %) and Rba. azotoformans KA25T (98.1 %) and clusters with other species of the genus Rhodobacter of the family Rhodobacteraceae. However, DNA-DNA hybridization with Rba. sphaeroides DSM 158T, Rba. megalophilus JA194T and Rba. azotoformans JCM 9340T showed relatedness of only 38-57% with respect to strain JA192T. On the basis of 16S rRNA gene sequence analysis, DNA-DNA hybridization data and morphological, physiological and chemotaxonomic characters, strain JA192T represents a novel species of the genus Rhodobacter, for which the name Rhodobacter johrii sp. nov. is proposed. The type strain is JA192T (=DSM 18678T =JCM 14543T =MTCC 8172T). © 2010 IUMS.