Abstract:A species-specific PCR assay was established for rapid and accurate detection of the oomycete pathogen Phytophthora tentaculata in diseased plant tissues and infected soil. A pair of species-specific primers Pt1/Pt2 were designed on the basis of Ras-related protein (Ypt1) gene sequences of the Phytophthora species. PCR amplification with the Pt primers resulted in a 386 bp product only from isolates of P. tentaculata. The detection threshold with Pt primers was 100 pg of genomic DNA. A nested PCR procedure was developed using Ypt1F/Ypt1R as the first-round amplification primers and Pt1/Pt2 as the second-round primers, which increased the detection sensitivity 100-fold to 1 pg. PCR using these Pt primers can also be used to detect P. tentaculata in naturally infected plant tissues and soil. The PCR-based method developed in this study provides a rapid and sensitive tool for detection of P. tentaculata.