Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/10/2005
Publication Date: 7/25/2005
Citation: Hughes, T.J., Vandemark, G.J. 2005. Interaction between aphanomyces euteiches and phytophthora medicaginis in resistant and susceptible alfalfa cultivars evaluated using real time pcr. Phytopathology. 94:S43.
Technical Abstract: Root rot diseases of alfalfa caused by Aphanomyces euteiches (Ae) and Phytophthora medicaginis (Pm) are controlled through a combination of cultural practices. Because Ae and Pm have been implicated in a damping-off disease complex, breeders often screen concurrently for resistance to both pathogens. Real-time PCR assays have been developed to quantify the amount of pathogen DNA present in roots of inoculated alfalfa. Results indicate that for both Ae and Pm, a negative and significant correlation exists between resistance and the amount of pathogen DNA present. Cultivars Saranac and WAPH-1 (susceptible and resistant, respectively, to Ae and Pm) were co-inoculated with spore suspensions of Ae, Pm, or both. The quantity of pathogen DNA detected was significantly lower for WAPH-1 than for Saranac when inoculated with either Ae or Pm. When inoculated with both Ae and Pm, the quantity of Pm DNA detected was significantly less than the amount of Pm DNA detected in plants inoculated with Pm alone. Results of these experiments suggest that co-inoculation with Ae and Pm reduces the colonization efficacy of Pm.