Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/8/1998
Publication Date: N/A
Citation: Interpretive Summary: The genetic relatedness among several species of the filamentous soil microorganism Streptomyces was determined as a continuation of an ongoing study of members of this group having red-colored spores. These microorganisms are the most numerous bacteria in all soils and produce the majority of commercially important antibiotics. The strains studied had been previously grouped into two groups, Streptomyces fulvissimus and Streptomyces griseoviridis, based on a statistical evaluation of their properties, but it was suspected that this method gave erroneous results. Measurement of the amount of DNA relatedness (i.e., genetic similarity) among these strains showed that numerical classification using statistical methods grouped most of the strains improperly and that they actually represent 13 distinct species. The data imply that the older classification of these microorganisms based on microscopic appearance, color, and limited physiological properties reflected the genetic relationship among the species better than does the more recent numerical taxonomic classification scheme.
Technical Abstract: As a continuation of an ongoing study of DNA relatedness among red- spored streptomycetes, the homology between the four species comprising the Streptomyces fulvissimus phenotypic cluster (S. fulvissimus, S. aureoverticillatus, S. longispororuber, and S. spectabilis) and the four species comprising the Streptomyces griseoviridis phenotypic cluster (S. griseoviridis, S. chryseus, S. daghestonicus, and S. murinus) was measured spectrophotometrically from C0t0.5 determinations. All strains were also compared to 12 strains representing previously determined DNA relatedness clusters in the Streptomyces lavendulae phenotypic cluster, including the type strain NRRL B-1230**T. The strains segregated into 15 cluster groups at DNA relatedness > 80%, including 10 single member clusters. S. griseoviridis and S. daghestonicus were synonymous, as were S. chryseus and S. longispororuber. S. spectablis exhibited species-level homology with strain NRRL B-2402, which had been received as S. lavendulae. S. aureoverticillatus exhibited significant DNA relatedness to S. flavotricini. None of the strains from the S. fulvissimus or S. griseoviridis clusters exhibited significant homology to the type strain of S. lavendulae.