Proposal of Streptomyces sporoverrucosus Gause et al. 1983 as a later heterotypic synonym of Streptomyces goshikiensis Niida et al. 1966 and an emended description of Streptomyces goshikiensis

The taxonomic relationship of Streptomyces goshikiensis and Streptomyces sporoverrucosus was re-evaluated using comparative genome analysis. The 16S rRNA gene sequence analysis indicated that S. goshikiensis JCM 4640(T) and S. sporoverrucosus CGMCC 4.1796(T) shared 100% sequence similarity. Phylogenetic analysis based on 16S rRNA gene and genomic sequences exhibited that they were closely related to each other. However, the values of average nucleotide identity (ANIb/ANIm) and digital DNA-DNA hybridization (dDDH) between the genomes of two type strains were 98.33%/98.69% and 87.2%, respectively, greater than the two recognized thresholds values of 96.7% ANI and 70% dDDH for species delineation. These results suggested that S. goshikiensis and S. sporoverrucosus should share the same taxonomic position. In addition, this conclusion was further supported by highly similar morphological, cultural, physiological, biochemical and chemotaxonomic characteristics between them. Consequently, it is proposed that S. sporoverrucosus is a later heterotypic synonym of S. goshikiensis.