Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2015
Publication Date: 1/6/2016
Publication URL: http://handle.nal.usda.gov/10113/62353
Citation: Labeda, D.P. 2016. Taxonomic evaluation of putative Streptomyces scabiei strains held in the ARS Culture Collection (NRRL) using multi-locus sequence analysis. Antonie Van Leeuwenhoek. 109(3):349-356. Interpretive Summary: Among the 7500 strains of soil microorganisms of the genus Streptomyces held in the ARS Culture Collection were 43 strains deposited as representatives of the potato-pathogenic species Streptomyces scabiei whose distribution is subject to plant quarantine regulations. These strains had been tentatively identified when added to the collection on the basis of their appearance and the fact that they had been isolated from potatoes, but they could now be definitively identified based on the partial gene sequences of 5 proteins important for cell function. It was discovered that 26 of these strains were members of the plant pathogenic species Streptomyces scabiei or Streptomyces europaeiscabiei, 4 likely represent new undescribed plant pathogens, and the remaining 13 strains were closely related to non-pathogenic species and thus could now be distributed without requiring a plant pest permit. The study demonstrates the value of this molecular diagnostic technique in characterizing microbial germplasm held in the collection in a relative quick and very sensitive manner so that this material can be properly cataloged and made available to the scientific public.
Technical Abstract: Multi-locus sequence analysis has been demonstrated to be a useful tool for identification of Streptomyces species and was previously applied to phylogenetically differentiate the type strains of species pathogenic on potatoes (Solanum tuberosum L.). The ARS Culture Collection (NRRL) contains 43 strains identified as Streptomyces scabiei deposited at various times since the 1950s and these were subjected to multi-locus sequence analysis utilising partial sequences of the house-keeping genes atpD, gyrB, recA, rpoB and trpB. Phylogenetic analyses confirmed the identity of 17 of these strains as Streptomyces scabiei, 9 of the strains as the potato-pathogenic species Streptomyces europaeiscabiei and 6 strains as potentially new phytopathogenic species. Of the 16 other strains, 12 were identified as members of previously described non-pathogenic Streptomyces species while the remaining 4 strains may represent heretofore unrecognised non-pathogenic species. This study demonstrated the value of this technique for the relatively rapid, simple and sensitive molecular identification of Streptomyces strains held in culture collections.