GrainGenes Reference Report: GNM-45-737
Reference
GNM-45-737
Title
Genetic mapping of the Lr20-Pm1 resistance locus reveals suppressed recombination on chromosome arm 7AL in hexaploid wheat
Journal
Genome
Year
2002
Volume
45
Pages
737-744
Author
Neu C Stein N Keller B
Abstract
Summary: The Lr20-Sr15-Pm1 resistance locus in hexaploid wheat confers resistance to three different fungal wheat pathogens (leaf rust, stem rust, and powdery mildew). It was previously localized in the distal region of chromosome arm 7AL. As a first step towards the isolation of this complex locus, we performed molecular mapping of the Lr20 and Pm1 genes in three F2 populations. In two populations, a cluster of 8 and 12 markers, respectively, cosegregated with the resistance genes. In a third population based on a cross between a susceptible lr20 mutant and a resistant cultivar, all clustered markers were monomorphic. However, in this population the recombination frequency proximal to the Lr20 gene was up to 60 times higher, indicating that the complete genetic linkage of the clustered markers is not due to a close physical linkage of the probes but is caused by suppressed recombination. This was supported by the analysis of Triticum monococcum BAC clones where no physical linkage between cosegregating probes was observed. Suppressed recombination at the Lr20-Pm1 locus is likely the result of an alien introgression of chromatin from an unidentified wild relative species or is due to chromosomal rearrangements
External Databases
Pubmed: 12175077
Gene
Pm1 (Triticum) Lr20 (Triticum) Sr15 (Triticum)
Locus
Pm1 Lr20 Sr15
Probe
STS638
Keyword
alien introgression
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GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture.
GrainGenes Reference Report: GNM-45-737
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GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture. | |||