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Recombination events generating a novel Rp1 race specificity
Shavannor M Smith1, Scot H Hulbert
1Department of Plant Pathology, Throckmorton Plant Science Center, Kansas State University, Manhattan, KS, USA.
Molecular Plant-Microbe Interactions : MPMI
|March 24, 2005
Summary
Maize Rp1 genes can recombine unequally during meiosis, generating new rust resistance specificities. Most novel resistance arises from the reassortment of existing Rp1 genes within the complex.
Area of Science:
- Genetics
- Plant Pathology
- Molecular Biology
Background:
- The maize Rp1 rust resistance complex is prone to meiotic mispairing.
- Unequal crossing over between Rp1 gene paralogs can generate novel resistance specificities.
Purpose of the Study:
- To investigate the mechanisms generating new rust resistance specificities at the maize Rp1 locus.
- To characterize recombinant haplotypes and their origins.
Main Methods:
- Analysis of progeny from an Rp1-D/Rp1-I heterozygote.
- Sequence comparisons of paralogs in recombinant and parental haplotypes.
- Identification and characterization of recombinant haplotypes.
Main Results:
- Four recombinant haplotypes with nonparental resistance specificity (Rp1-I*) were identified.
- All recombinants originated from intergenic recombination events between Rp1 genes.
- The HRp1-I parental haplotype contains at least 41 rp1 genes, with 31 transcribed.
Conclusions:
- Novel rust resistance specificities at the maize Rp1 locus primarily result from the reassortment of existing Rp1 genes.
- Intergenic recombination is a key mechanism driving the evolution of resistance specificities in the Rp1 complex.