Location: National Germplasm Resources Laboratory
Project Number: 8042-22000-302-019-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2019
End Date: Sep 30, 2021
Research Objectives: 1) Collect pathogenic and non-pathogenic Streptomyces spp. from PCS suppressive and conducive soil; 2) Phenotypically characterize recovered pathogenic and non-pathogenic (antagonistic) Streptomyces spp.; 3) Compare the viriome associated with recovered pathogenic and non-pathogenic Streptomyces spp. isolates; and 4) Determine the diversity of Streptomyces spp. communities associated with PCS suppressive and non-suppressive soil using high-throughput sequencing.
Objective 1. Streptomyces spp. isolation. Isolates of Streptomyces spp. will be recovered from PCS infected tubers and soil sampled randomly from suppressive soil plots. Individual bacterial suspensions will be spread onto media and Streptomyces spp. colonies will be picked with a sterile inoculation loop and transferred to obtain pure culture. (to be conducted by: The University of Minnesota). Objective 2. Phenotypic characterization of Streptomyces spp. Colony morphology, ability to produce pigment, and pigmentation color will be determined for each Streptomyces spp. isolate in different growth media. Phenotypic fingerprinting of Streptomyces spp. isolates will be assessed using the BIOLOG OmniLog GEN III microplate system. Total thaxtomin A production will be determined for individual Streptomyces isolates. (to be conducted by: The University of Minnesota). Objective 3. Comparative viriome analysis of pathogenic and non-pathogenic Streptomyces spp. The 60 pathogenic and non-pathogenic Streptomyces spp. isolates, 20 per location characterized above, will be screened using high throughput sequencing (HTS) technology on Illumina NextSeq platform. This approach will compare the viriome between antagonists from suppressive soils vs. pathogens from conducive soils of each Streptomyces spp. isolate. (to be conducted by: ARS). Objective 4. Diversity of Streptomyces spp. from PCS suppressive and non-suppressive soil. Ribosomal 16S fragments will be amplified from soil DNA samples using the coded-primer (tag) approach to multiplex pyrosequencing. DNA isolated as described above will be used as template for PCR amplification of the V1-V3 region of the 16S rRNA gene. (to be conducted by: The University of Minnesota).