A framework for gene mapping in wheat demonstrated using the Yr7 yellow rust resistance gene

Area of Science:

• Plant Genetics
• Crop Improvement
• Wheat Breeding

Background:

• Yellow rust, caused by Puccinia striiformis, is a major disease affecting wheat production globally.
• Identifying resistance genes like Yr7 is crucial for developing resistant wheat varieties and ensuring food security.

Purpose of the Study:

• To map the yellow rust resistance gene Yr7 in wheat.
• To identify single nucleotide polymorphisms (SNPs) associated with Yr7.
• To validate the utility of mapping-by-sequencing for gene discovery in wheat.

Main Methods:

• Quantitative trait locus (QTL) mapping using a double haploid (DH) population.
• Association mapping using an association panel.
• SNP array genotyping and mapping-by-sequencing of resistant and susceptible DH bulks.

Main Results:

• Yr7 was mapped to a low-recombination region on chromosome 2B.
• Fine mapping narrowed the Yr7 interval to a single haplotype block.
• Mapping-by-sequencing identified a candidate gene homologous to a previously suggested Yr7 candidate.

Conclusions:

• Combining QTL mapping, association mapping, and mapping-by-sequencing offers a powerful strategy for precise gene mapping.
• The developed methodology is broadly applicable to various traits in crop improvement.
• This study successfully defined a small interval containing the causative gene for Yr7 resistance in wheat.