Characterization and high-resolution mapping of a late blight resistance locus similar to R2 in potato.
Identification of resistance (R) genes to Phytophthora infestans is an essential step in molecular breeding of potato. We identified three specific R genes segregating in a diploid mapping population. One of the R genes is located on chromosome 4 and proved phenotypically indistinguishable from the Solanum demissum-derived R2, although S. demissum is not directly involved in the pedigree of the population. By bulked segregant analysis combined with a resistance assay, a genetic linkage map of the R2-like locus was constructed with 30 coupling and 23 repulsion phase AFLP markers. Two markers flanking the R2-like locus were applied to screen an extended population of 1,586 offspring. About 103 recombinants were selected, and an accurate high-resolution map was constructed. The R2-like resistance was localized in a 0.4 cM interval and was found co-segregating with four AFLP markers, which can be used to isolate the R2-like gene by map-based gene cloning. By analyzing race-specificity and R gene-specific molecular markers, we also found that an R1-like gene and an additional unknown R gene are segregating in the population.
Park
T H
TH
Department of Plant Sciences, Laboratory of Plant Breeding, Graduate School Experimental Plant Sciences, Wageningen University, Binnenhaven 5, 6709 PD, Wageningen, The Netherlands.
Vleeshouwers
V G A A
VG
Huigen
D J
DJ
van der Vossen
E A G
EA
van Eck
H J
HJ
Visser
R G F
RG
D002874:Chromosome Mapping; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D010838:Phytophthora / Q000472:pathogenicity*; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D032322:Solanum / Q000235:genetics* / Q000382:microbiology*; D011198:Solanum tuberosum / Q000235:genetics* / Q000382:microbiology*; D013045:Species Specificity
D018744:DNA, Plant