Taxonomic study of a chromomycin-producing strain and reclassification of Streptomyces cavourensis subsp. washingtonensis as a later synonym of Streptomyces griseus

A chromomycin-producing actinomycete, strain AP19, was isolated from a sample of faeces collected from Foping national nature reserve in China. Chemotaxonomic and morphological properties indicated that the novel isolate was a member of the genus Streptomyces. Phylogenetic analyses based on an almost complete 16S rRNA gene sequence of the strain and on the 120-nt nucleotide variable gamma-region of this molecule revealed that it was closely related to Streptomyces griseus ISP 5236(T) and Streptomyces cavourensis subsp. washingtonensis ATCC 27732(T). DNA-DNA relatedness values among these strains were above 70 %. Streptomyces cavourensis subsp. washingtonensis could be readily distinguished from Streptomyces cavourensis ATCC 14889(T) by differing BOX-PCR fingerprinting patterns, relatively low 16S rRNA gene sequence similarity and a low DNA-DNA relatedness value. It is proposed, therefore, that Streptomyces cavourensis subsp. washingtonensis is a later synonym of Streptomyces griseus.