Downy mildew is one of the more damageable diseases on grapevine. To avoid the use of phytochemicals, an alternative is the breeding of resistant varieties carrying resistance factors. The American species Vitis rotundifolia is totally resistant to downy mildew. Genetic mapping of resistance loci in V. rotundifolia cv. Trayshed identified a locus for total resistance to downy mildew, named Rpv2, which is localized on chromosome 18 in a region containing a cluster of TIR-NBS-LRR genes. Gene annotation associated with their putative function and their expression analysis during infectious cycle, allowed identification of two candidate genes for Rpv2 resistance. Functional validation to determine which gene confers the resistance associated to Rpv2 is in progress. Knowledge of Rpv2 resistance mechanism and of its potential breakdown will permit us to evaluate whether this gene would be suitable for integrating future breeding programs for new resistant grapevine varieties.