Monitoring of diseases caused by pathogenic oomycetes using DNA analysis

Phytophthora species are best known as pathogens of agricultural crops (e.g. P. infestans), but there are also invasive pathogens destroying forest atands (e.g. P. ramorum in the USA) or even whole forest ecosystems (e.g. P. cinnamomi in Australia). Still, little is known about indiginous species, especially in wild ecosystems. Rhododendrons are well known as a reservuar for oomycetes’ development. The main objectives of the present study were to develop the new tool for the identification of pathogenic Phytophthora and Phytium based on DNA sequence analysis of the ITS1, 5.8S gene and ITS2 region. Rhododendrons leaves served as specific plant baits. In order to reach the goal the real time PCR, the nested PCR and the DNA sequencing of the rDNA ITS region were carried out. The genomic DNA was extracted form the symptomatic rhododendron leaves. Three distinct Oomycetes species: Phytophthora cactorum, Pythium mercuriale and em>Pythium recalcitrans were detected in rhododendron leaves and registered in GenBank