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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Research Project #419851

Research Project: Molecular diagnostics of Phytophthora Spp. from natural ecosystems

Location: Crop Improvement and Protection Research

2011 Annual Report

1a. Objectives (from AD-416)
To validate molecular diagnostic tools for identification of Phytophthora ramorum, the pathogen responsible for sudden oak death.

1b. Approach (from AD-416)
Two different molecular diagnostic techniques will be evaluated for their effectiveness in identifying Phytophthora species in infected plant tissue using samples collected from different regions of the USA. One procedure is a TaqMan real time PCR diagnostic marker that exhibits specificity at a genus level (it can identify Phytophthora spp. present) in addition to a species level (different probes can differentiate P. ramorum or P. kernoviae from other species). The second procedure is for determination of mitochondrial haplotype of P. ramorum, which so far has been correlated with the nuclear genotype. The technique uses melt curve analysis to make the determination, which takes much less time than conventional techniques for genotype determinations.

3. Progress Report
The objective of the project is to optimize and fully validate a new molecular diagnostic technique for Phytophthora spp. that was developed as part of CRIS 5305-22000-12-06R, "Development of a systematic approach for marker selection in Phytophthora using mitochondrial genomic sequences." DNA from field samples collected as part of the state's ongoing survey for P. ramorum have been obtained from a collaborator at the California Department of Agriculture, Sacramento, from a diagnostician at Oregon State University who is managing the national survey of P. ramorum for the west coast, and a diagnostician at Penn State University who is managing the samples from the national survey of P. ramorum for the eastern part of the country. These samples were used to validate the diagnostic technique and are currently undergoing sequence analysis to confirm the identification of the species that are present. Communication on the project status is done with the granting agency by e-mail and submission of written yearly progress reports.

4. Accomplishments