Sequence analysis of loci Rpv10 and Rpv3 for resistance against grapevine downy mildew (Plasmopara viticola)

The oomycete Plasmopara viticola is one of the most important pathogens of grapevine (Vitis vinifera L.). All traditional European cultivars used for wine production are highly susceptible. Therefore a great quantity of fungicides is necessary to enable high quality production of grapes. Newly bred resistant cultivars generated via marker-assisted selection (MAS) are a major contribution toward reducing fungicide applications for more sustainable viticulture. Identification of specific markers linked to resistance loci is crucial to facilitate high throughput screening in a breeding program. Many North American Vitis species carry resistance genes due to co-evolution with Plasmopara viticola. Some Asian Vitis species also exhibit such resistances although their evolutionary origin is not yet understood. Among others, the two loci Rpv3 (American origin, e.g., ?Regent?) and Rpv10 (Asian origin, e.g., ?Solaris?) have been identified in earlier studies. Analysis of the genomic DNA sequence of ?Solaris? at the Rpv10 locus and ?Villard Blanc? at the Rpv3 locus revealed several candidate genes which might be responsible for the expression of resistance against Plasmopara viticola. These candidates include six genes with protein domains similar to resistance proteins known from other plant species. The aim of the study is the elucidation of the cellular defense mechanisms and the development of gene-linked markers for high throughput screening in grapevine breeding.