Document Type: Research Paper
Department of Microbiology, School of Veterinary Medicine, Lorestan University, Khorramabad, I.R. Iran.
2School of Biology, University of Newcastle, Newcastle Upon Tyne, NE1 7RU, United Kingdom.
In an extensive numerical phenetic survey, a number
of blue, red and gray spored streptomycete strains
were grouped together as Streptomyces cyaneus
species-group, a taxon which encompasses strains
known to produce antitumor antibiotics, notably anthracyclines.
In the present investigation these and related
streptomycetes were the subject of morphological and
16S rRNA sequencing studies designed to clarify their
taxonomic relationships. It is evident from these results
that the Streptomyces cyaneus species-group encompasses
misclassified strains and members of several
distinct species. However, some of the red-spored
strains (e.g. Streptomyces janthinus ISP 5206T,
Streptomyces roseoviolaceus ISP 5277T and
Streptomyces violatus ISP 5209T) formed a distinct
clade. In contrast, most of the blue and gray-spored
strains showed much less sequence homology
between and with one another and were scattered
throughout the 16S rRNA Streptomyces tree. The
improved classification of this group of streptomycetes
provides an essential basis for establishing their industrial
and economical significance.