Fine mapping of the clubroot resistance gene, Crr3, in Brassica rapa.
A linkage map of Chinese cabbage (Brassica rapa) was constructed to localize the clubroot resistance (CR) gene, Crr3. Quantitative trait loci analysis using an F(3) population revealed a sharp peak in the logarithm of odds score around the sequence-tagged site (STS) marker, OPC11-2S. Therefore, this region contained Crr3. Nucleotide sequences of OPC11-2S and its proximal markers showed homology to sequences in the top arm of Arabidopsis chromosome 3, suggesting a synteny between the two species. For fine mapping of Crr3, a number of STS markers were developed based on genomic information from Arabidopsis. We obtained polymorphisms in 23 Arabidopsis-derived STS markers, 11 of which were closely linked to Crr3. The precise position of Crr3 was determined using a population of 888 F(2) plants. Eighty plants showing recombination around Crr3 locus were selected and used for the mapping. A fine map of 4.74 cM was obtained, in which two markers (BrSTS-41 and BrSTS-44) and three markers (OPC11-2S, BrSTS-54 and BrSTS-61) were cosegregated. Marker genotypes of the 21 selected F(2) families and CR tests of their progenies strongly suggested that the Crr3 gene is located in a 0.35 cM segment between the two markers, BrSTS-33 and BrSTS-78.
Saito
M
M
Graduate School of Agriculture, Kyoto Prefectural University, Kyoto Prefectural Institute of Agricultural Biotechnology, 74 Oji, Kitainayazuma, Seika, Soraku, Kyoto, 619-0244, Japan.
Kubo
N
N
Matsumoto
S
S
Suwabe
K
K
Tsukada
M
M
Hirai
M
M
D017360:Arabidopsis / Q000235:genetics; D029741:Brassica rapa / Q000235:genetics*; D002874:Chromosome Mapping; D017343:Genes, Plant; D005819:Genetic Markers; D018745:Genome, Plant; D010935:Plant Diseases / Q000235:genetics*; D040641:Quantitative Trait Loci
D005819:Genetic Markers