DEOXYRIBONUCLEIC-ACID RELATEDNESS AMONG SPECIES OF THE STREPTOMYCES-CYANEUS CLUSTER

The genetic diversity among strains in the phenetically defined "Streptomyces cyaneus" cluster was evaluated by DNA hybridization. The DNA relatedness data support the reduction of the blue-spored species S. bellus and S. curacoi to synonomy with S. coeruleorubidus, and the red-spored species S. afghaniensis, S. janthinus, S. roseoviolaceus, and S. violatus to synonomy with S. purpurascens. Most of the strains in this phenetic cluster exhibit DNA relatedness < 60%, but > 40% with the other strains in the cluster, providing genetic evidence in support of the species group or sibling species concept. S. cyaneus is one of the most genetically distant strains in the cluster, exhibiting only low, genus-background relatedness to the other strains. Emended descriptions of Streptomyces coeruleorubidus and Streptomyces purpurascens are given.