Abstract
Black spot disease of rose, incited by the fungus Diplocarpon rosae, is found worldwide and is the most important disease of garden roses. A gene-for-gene interaction in this pathosystem is evidenced by the presence of pathogenic races of D. rosae and the previous discovery of a dominant resistance allele at the Rdr1 locus in the diploid Rosa multiflora. The objective of the present study was to genetically analyze resistances to North American black spot races 3, 8, and 9 previously reported in tetraploid roses. Resistance to North American races 3 and 8 segregated 1:1 in multiple F1 populations, indicating that both are conferred by dominant alleles at single loci and are present in simplex (Rrrr) configuration. Gene pyramiding was demonstrated by combining both resistances into single genotypes. Resistance to race 9 was partial and segregated in a quantitative fashion. Analysis of these populations with microsatellite markers previously developed for Rdr1 revealed that the gene conferring race 3 resistance resides within the same R gene cluster as Rdr1. Race 8 resistance segregated independently and is, therefore, a novel locus for black spot resistance in rose which we have named Rdr3. NBS and LRR profiling were used in a bulked segregant analysis to identify a marker 9.1 cM from Rdr3, which was converted to a SCAR marker form for marker-assisted breeding.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 573-585 |
| Number of pages | 13 |
| Journal | Theoretical and Applied Genetics |
| Volume | 120 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jan 2010 |
Bibliographical note
Funding Information:The authors thank Dr. David Zlesak for contributing expertise in rose germplasm resources and assistance with disease ratings and Dr. Ron Phillips for lending expertise with tetraploid segregation models. Thanks also to Ann-Katrin Lühmann for preparation and shipment of D. rosae isolates, Kathy Zuzek for assistance with controlled crosses and, Brandi Miatke for assistance with inoculations. This manuscript is Scientific Journal Series No. 091210185 of the Department of Horticultural Science, University of Minnesota and has been supported by the Minnesota Agricultural Experiment Station, the University of Minnesota Graduate School, and a National Science Foundation Central European Summer Research Institute fellowship.