Abstract
The taxonomic position of two soil isolates, 3-46-b(3)(T) and 3-45-a(11)(T), was clarified based on data from a polyphasic study. The organisms showed a combination of chemotaxonomic and morphological properties typical of the genus Actinomadura. They formed distinct phyletic lines in the Actinomadura 16S rRNA gene tree and were closely associated with the type strains of Actinomadura meyerae (sequence similarity of 98.3-98.5 %), Actinomadura napierensis (98.1-98.3 %) and Actinomadura latina (96.4-96.8 %). The level of 16S rRNA gene sequence similarity between the new isolates was 99.1 %. The level of DNA-DNA hybridization between strains 3-46-b(3)(T) and 3-45-a(11)(T) was 43.6 % and levels of relatedness between the two new isolates and the type strains of A. meyerae and A. napierensis were 21.0-27.3 %. On the basis of phenotypic and genotypic properties, the new isolates could be differentiated from each other and from their closest phylogenetic relatives. It is proposed that the organisms be classified as representing two novel species of the genus Actinomadura. The names proposed for these taxa are Actinomadura bangladeshensis sp. nov. [type strain 3-46-b(3)(T) =JCM 13933(T) =MTCC8057(T)] and Actinomadura chokoriensis sp. nov. [type strain 3-45-a(11)(T) =JCM 13932(T) =MTCC8056(T)].