ARS | Publication request: Systematics of the genus Streptomyces: will a phylogeny based on 16S ribosomal RNA genes yield taxonomic resolution or confusion?

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 2008
Publication Date: October 21, 2008
Citation: Labeda, D.P. 2008. Systematics of the genus Streptomyces: will a phylogeny based on 16S ribosomal RNA genes yield taxonomic resolution or confusion?. Meeting Abstract.

Technical Abstract: Species of the bacterial genus Streptomyces are a predominant component of the microbial population of soil throughout the world, where they are thought to contribute to the degradation of complex organic materials and facilitate nutrient recycling. Streptomyces species produce a wide array of medically and commercially important secondary metabolites, such as streptomycin and chlortetracycline, and members of this genus were of particular interest during the pharmaceutical industry's "golden age" of antibiotics. The systematics of the genus Streptomyces, which has the greatest number of validly described species of any bacterial genus, has long been a challenge. The classification of Streptomyces species was originally based almost exclusively on morphological characteristics, a factor that contributed to the large number of valid and invalid species described in the literature and patents. Over the years, researchers have applied different methods, such as numerical taxonomic analysis of phenotypic traits or various molecular biology techniques, to clarify the species concept in Streptomyces and simplify the identification of newly isolated strains. The 16S rRNA gene sequences for virtually all validly described species within the family Streptomycetaceae, which contains the genus Streptomyces and others, are now available from the public sequence databanks and it is possible to calculate phylogenetic relationships among the species. However, because of the relatively high similarity in 16S rRNA gene sequence among almost all species, it may not be feasible to propose phylogenetic relationships between individual species or species groups based on this gene alone, although nearly identical similarity of this sequence is a strong indication of identity. The study of sequences of multiple housekeeping protein-coding genes may provide some insight into the phylogenetic relationships among species. It is possible, however, to examine the distribution of phenotypic characteristics such as morphology or secondary metabolites as related to the overall phylogeny of the species within the Streptomycetaceae.