The taxonomic position of ten acidophilic actinomycetes isolated from an acidic rice-field soil was established using a polyphasic approach. 16S rRNA gene sequences determined for the isolates were aligned with corresponding sequences of representatives of the genera Kitasatospora, Streptacidiphilus and Streptomyces and phylogenetic trees were inferred using four tree-making algorithms. The isolates had identical sequences and formed a distinct branch at the periphery of the Streptacidiphilus 16S rRNA gene tree. The chemotaxonomic and morphological properties of representative isolates were consistent with their assignment to the genus Streptacidiphilus. The isolates shared nearly identical phenotypic profiles that readily distinguished them from representatives of the established species of Streptacidiphilus. It is evident from the genotypic and phenotypic data that the isolates form a homogeneous group that corresponds to a novel species in the genus Streptacidiphilus. The name proposed for this new taxon is Streptacidiphilus oryzae sp. nov.; the type strain is strain TH49(T) (=CGMCC 4.2012(T) = JCM 13271(T)).
