Reclassification of 15 Streptomyces species as synonyms of Streptomyces albogriseolus, Streptomyces althioticus, Streptomyces anthocyanicus, Streptomyces calvus, Streptomyces griseoincarnatus, Streptomyces mutabilis, Streptomyces pilosus or Streptomyces rochei

Int J Syst Evol Microbiol. 2019 Jun;71(3). doi: 10.1099/ijsem.0.004718. Epub 2021 Mar 1.


Taxonomic relationships in eight sets of Streptomyces species, (1a) Streptomyces enissocaesilis, Streptomyces plicatus, Streptomyces rochei and Streptomyces vinaceusdrappus, (1b) Streptomyces geysiriensis, (2) Streptomyces luteus and Streptomyces mutabilis, (3) Streptomyces flavoviridis and Streptomyces pilosus, (4) Streptomyces asterosporus and Streptomyces calvus, (5) Streptomyces erythrogriseus, Streptomyces griseoincarnatus, Streptomyces labedae and Streptomyces variabilis, (6a) Streptomyces griseorubens, (6b) Streptomyces matensis, (6c) Streptomyces althioticus, (7) Streptomyces albogriseolus and Streptomyces viridodiastaticus, (8a) Streptomyces humiferus and Streptomyces violaceolatus, (8b) Streptomyces anthocyanicus, Streptomyces coelescens and Streptomyces violaceoruber, were investigated. Type strains within each subset of 1a to 8b shared completely identical 16S rRNA gene sequences. In MLSA, subsets 1a and 1b, 6a to 6c, and 8a and 8b formed an independent clade, respectively, but the evolutionary distances between S. violaceoruber and the other members in set 8 and between S. griseorubens and those in set 6 were 0.022-0.023 and 0.0064-0.0076, respectively. Members in each of the other sets, except for S. labedae, formed an independent clade. In each clade, evolutionary distances between/among the members were <0.007 except for that between S. griseorubens and S. matensis in set 6, suggesting the same species. Digital DNA-DNA relatedness using whole genome sequences and phenotypic similarities supported the synonymies of sets 1 to 3, set 4 except for S. labedae, sets 5 to 7, and set 8 except for S. violaceoruber, respectively. Therefore, S. enissocaesilis, S. geysiriensis, S. plicatus and S. vinaceusdrappus were considered as later heterotypic synonyms of S. rochei; S. luteus as that of S. mutabilis; S. flavoviridis as that of S. pilosus; S. asterosporus as that of S. calvus; S. erythrogriseus and S. variabilis as those of S. griseoincarnatus; S. griseorubens and S. matensis as that of S. althioticus; S. viridodiastaticus as that of S. albogriseolus; S. coelescens, S. humiferus and S. violaceolatus as those of S. anthocyanicus.

Keywords: MLSA, synonym; Streptomyces; reclassification.