1a.Objectives (from AD-416)
Confirmation of Clavibacter michiganensis subsp. sepedonicus infections using a multiplex real-time PCR assay for ring rot diagnosis and potato seed lot screening.
1b.Approach (from AD-416)
Real-time PCR primers and fluorescently labeled Taqman probes were previously developed for detection of three unique areas of the bacterial genome of C. michiganensis subsp. sepedonicus (Cms), the causal agent of bacterial ring rot (BRR) of potato. These genomic regions code for cellulose genes (CelA and CelB) that are primary virulence determinants for Cms. These reagents will be used for additional screening of bacterial potato endophytes by a multiplex real-time PCR to verify specificity and reliability of the procedure for Cms detection and identification.
A molecular test was used in conjunction with an antibody-based test for detection of strains of Potato virus Y (PVY) and other viruses. Numerous samples from the central United States were analyzed in order to determine the incidence of the different strains of PVY prevalent in different parts of the country. Results showed the recombinant “N:O” strain has become the predominant virus. This indicates a change from the previously prevalent “O” strain of the virus. This is significant because the “N:O” strain, and not the “O” strain, is capable of producing severe symptoms in potato tubers and therefore significant reduction in the crop quality. Other necrotic strains of PVY were also detected. Potato mop top virus (PMTV) and Tobacco rattle virus (TRV) are both important soil-borne viruses and were also detected in the survey. Detection of these viruses alerts growers, field-men, and diagnostic laboratories to the presence of these important viruses in potato-producing regions of the central United States.
This project investigates the role of various viruses, especially tobacco rattle virus, potato mop top virus, and potato virus Y, in production of necrosis in potato tubers, which contributes directly to objective 2 of the in-house project.
Progress on the project was monitored by email and phone conversations.