Reclassification of Streptomyces griseostramineus as a synonym of Streptomyces griseomycini based on a polyphasic taxonomic approach.

Abstract

In the present work, the taxonomic relationship between Streptomyces griseomycini and Streptomyces griseostramineus was reevaluated by a comprehensive comparison of phenotypic, chemotaxonomic and genomic characteristics, as well as phylogeny. Phylogenetic analysis based on 16S rRNA gene sequences and whole-genome sequences indicated that Streptomyces griseostramineus JCM 4385T was clustered together with Streptomyces griseomycini JCM 4382T, suggesting they were closely related to each other. However, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between their genomes were 99.7 and 97.5 %, respectively, much larger than the recommended threshold values of 96.7 % ANI and 70 % dDDH for Streptomyces species delineation. In addition, the morphological, cultural, physio-biochemical and chemotaxonomic features of these two species further demonstrated that they belonged to the same genome species. Based on the above data and the principle of priority in nomenclature, it is proposed that S. griseostramineus (Preobrazhenskaya et al. 1957) Pridham et al. 1958 (Approved Lists 1980) is a later heterotypic synonym of S. griseomycini (Preobrazhenskaya et al. 1957) Pridham et al. 1958 (Approved Lists 1980).