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New advances in molecular diagnostics for Phytophthora tentaculata
T. D. MILES (1), F. N. Martin (2). (1) California State University Monterey Bay, Seaside, CA, U.S.A.; (2) USDA-ARS, Salinas, CA, U.S.A.

<i>Phytophthora tentaculata</i> has become an important invasive pathogen in restoration nurseries along coastal California. Recently, two mitochondrial loci (i.e. <i>atp9-nad9</i> and <i>trnM-trnP-trnM</i>) have been identified in <i>Phytophthora</i> spp. that are useful for genus and species specific detection. A significant sequence database for both loci was developed from isolates that were obtained from the World <i>Phytophthora</i> Genetic Resource Collection. Using these mitochondrial loci a TaqMan species and genus specific assay was developed for 50 <i>Phytophthora</i> spp., one of which was <i>P. tentaculata.</i>  This <i>P. tentaculata </i>specific TaqMan assay is sensitive down to 50-100 fg of purified DNA, has been tested for specificity on over 130 <i>Phytophthora </i>taxa and been validated on <i>P. tentaculata</i>-infected plant tissue. Furthermore, a new isothermal diagnostic technique known as recombinase polymerase amplification has been developed using these same mitochondrial loci that allows for genus and species specific detection of <i>P. tentaculata</i> directly in the field without the need for DNA extraction. Hopefully with the development of these tools researchers and regulators can actively track <i>P. tentaculata </i>on infected plant material and in environmental samples to develop best management practices for its control in the nursery system.

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