Molecular Markers for Identification of P. ramorum and Other Phytophthora species From Diseased Tissue

Molecular techniques have been developed for detection and identification of P. ramorum and other Phytophthora species that are based on the mitochondrially encoded sequences. One technique uses a Phytophthora genus specific primer to determine if a Phytophthora species is present, followed by a nested amplification with species-specific primers to determine if the pathogen is P. ramorum or one of several other species (such as P. nemorosa or P. pseudosyringe). This procedure also uses a plant primer pair to serve as a positive control ensuring the ability of the template DNA to amplify. These species-specific and plant markers have been modified for use with real-time PCR. A second technique relies on RFLP analysis of the Cox I and II gene cluster to identify isolates of Phytophthora to a species level.