Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/16/2007
Publication Date: 6/15/2007
Citation: Goodfellow, M., Kumar, Y., Labeda, D.P., Sembiring, L. 2007. The Streptomyces violaceusniger clade: a home for streptomycetes with rugose ornamented spores. Antonie Van Leeuwenhoek. 92:173-199. Interpretive Summary: Strains of the soil bacterial species Streptomyces hygroscopicus and Streptomyces violaceusniger are of great interest for biotechnology because of their production of a variety of interesting natural products, including antibiotics. The visual appearance of these strains has long been used to classify them and it was suspected that this method was inadequate. A polyphasic taxonomic study was undertaken of a number of strains deposited in culture collections as Streptomyces hygroscopicus and Streptomyces violaceusniger and the morphology, physiology, and sequences of both the 16S ribosomal RNA gene and part of the RNA polymerase beta subchain were determined and compared. It was discovered that morphological appearance was indeed inadequate for identification of these strains and five new species of Streptomyces were described, including S. auratus sp. nov., S. demainii, sp. nov., S. phaeoluteichromatogenes sp. nov., S. phaeogriseichromatogenes sp. nov., and S. phaeoluteigriseus sp. nov.. The study also provided additional support for three phylogenetically related species proposed in an earlier study, including Streptomyces albiflaviniger sp. nov., Streptomyces geldanamycininus sp. nov., and Streptomyces griseiniger sp. nov., and detailed morphological and physiological characteristics that permit differentiation between all of the species.
Technical Abstract: The taxonomic status of 16 strains received as Streptomyces hygroscopicus, Streptomyces melanosporofaciens, Streptomyces sparsogenes, Streptomyces sporoclivatus and Streptomyces violaceusniger was evaluated in a polyphasic study. Eleven of the organisms formed a distinct clade in the Streptomyces 16S rRNA gene tree with the type strains of Streptomyces asiaticus, Streptomyces cangkringensis, Streptomyces indonesiensis, Streptomyces javensis, Streptomyces malaysiensis, Streptomyces rhizosphaericus, Streptomyces yatensis and Streptomyces yogyakartensis, and this entire group formed rugose ornamented spores in spiral spore chains. These strains were assigned to three established and three novel species, namely Streptomyces albiflaviniger sp. nov., Streptomyces geldanamycininus sp. nov., Streptomyces griseiniger sp. nov., and Streptomyces hygroscopicus, Streptomyces melanosporofaciens and Streptomyces violaceusniger. It is also proposed that Streptomyces sporoclivatus becomes a subjective synonym of Streptomyces melanosporofaciens. Streptomyces sparsogenes NRRL 2940T, which produced ridged ornamented spores in spiral spore chains, formed a distinct phyletic line in the 16S rRNA gene tree and was readily distinguished from the others using a range of phenotypic properties. Streptomyces violaceusniger strains NRRL 8097, NRRL B-5799, NRRL 2834 and NRRL ISP 5182 fell outside the Streptomyces violaceusniger 16S rRNA clade and formed either smooth or ridged ornamented spores in either flexuous or spiral spore chains. These organisms were distinguished from one another and from their closest phylogenetic neighbors and were considered to merit species status as Streptomyces auratus sp. nov., Streptomyces phaeoluteichromatogenes sp. nov., Streptomyces phaeogriseichromatogenes sp. nov., and Streptomyces phaeoluteigriseus sp. nov., respectively.