Rdrl is the first monogenic dominant resistance gene described in the genus Rosa that is active against black spot of roses caused by Diplocarpon rosae, a facultative biotrophic parasitic ascomycete. It was introgressed from the wild rose species Rosa multiflora. According to the previous studies, the Rdr1 resistance locus carries nine copies of resistance gene analouges (RGA) of the Toll-interleukin 1 receptor (TIR), nucleotide binding site (NBS), leucine rich repeat (LRR) type within an interval of 220Kb of DNA. In the present study, the functional characterization of Rdr1 candidates led to...