Reclassification of Streptomyces costaricanus and Streptomyces phaeogriseichromatogenes as later heterotypic synonyms of Streptomyces murinus

This study aimed to clarify the taxonomic relationships among Streptomyces costaricanus, Streptomyces graminearus, Streptomyces murinus and Streptomyces phaeogriseichromatogenes. These strains share the same 16S rRNA gene sequence. Multilocus sequence analysis revealed that S. costaricanus, S. murinus and S. phaeogriseichromatogenes belong to the same species, but S. graminearus does not. Digital DNA?DNA relatedness and average nucleotide identity among S. costaricanus, S. murinus and S. phaeogriseichromatogenes were 70.9?74.6% and 96.5?97.0 %, respectively. In addition to the previously reported phenotypic data, the presence of a similar set of secondary metabolite- biosynthetic gene clusters for polyketides and nonribosomal peptides supported the similarity among the three species. Therefore, S. costaricanus and S. phaeogriseichromatogenes should be reclassified as later heterotypic synonyms of S. murinus.

Automated summary

This study aimed to clarify the taxonomic relationships among Streptomyces costaricanus, Streptomyces murinus and Streptomyces phaeogriseichromatogenes using multilocus sequence analysis and bioinformatics methods, revealing that these three strains should be classified as the same species. The presence of a similar set of secondary metabolite-biosynthetic gene clusters for polyketides and nonribosomal peptides further supported their similarity. Therefore, S. costaricanus and S. phaeogriseichromatogenes should be reclassified as later heterotypic synonyms of S. murinus.