Identification of the Causal Agent of Grapevine Downy Mildew Plasmopara viticola Based on Quantitative PCR

A new method is proposed for early identification of the causal agent of grapevine downy mildew Plasmopara viticola, based on a real-time quantitative PCR (real-time PCR) method using the fluorescent dye SYBR Green I. Six pairs of primers were developed for real-time PCR for identification of P. viticola; among them, the primer pair PvITS1_2-real-s/a demonstrated the highest efficiency for early detection of grapevine downy mildew. Moreover, a positive correlation (R = 0.86) was demonstrated when comparing the results of real-time PCR with the primers PvITS1_2-real-s/a with data on metataxonomic analysis of the distribution of P. viticola among plants of Far Eastern grape species and varieties. Thus, real-time PCR with the primer pair PvITS1_2-real-s/a is a cheap and efficient method for early detection and monitoring of asymptomatic P. viticola infections. The developed method can be a basis for predicting epidemics of grapevine downy mildew and its control in vineyards.