A simple method for extracting DNA from rhododendron plants infected with Phytophthora spp. for use in PCR

Among the numerous protocols that describe the extraction of DNA, those relating to the isolation of DNA from infected plants, are rare. This study describes a rapid and reliable method of extracting a high quality and quantity of DNA from rhododendron leaves artificially infected with Phytophthora cactorum, P. cambivora, P. cinnamomi, P. citrophthora, and P. plurivora. The use of the modified Doyle and Doyle protocol (1987) allowed us to obtain high quantity and quality DNA (18.26 μg from 100 mg of the fresh weight of infected leaves at the ratios of A260/280 and A260/230 – 1.83 and 1.72, respectively), suitable for conventional polymerase chain reaction (PCR) and real-time PCR amplifications.