Tilling for Disease Resistance Genes

Mutagenized populations of wheat provide an invaluable resource for both forward and reverse genetics screens. To enhance genomic toolkit of wheat researchers, we designed wheat exome capture and applied it for targeted re-sequencing of mutagenized population of tetraploid wheat Triticum turgidum cv ‘Kronos’. We now sequenced over 1,000 mutant wheat lines, identified the mutations in the protein-coding sequences and computationally predicted mutation effect on protein function. We are cataloguing discovered mutations in a reverse genetics database that will be publicly available to scientists and wheat breeders (See computer demo presentation by Hans Vasquez Gross, also in this meeting). To leverage this resource for fighting wheat pathogens, we have predicted components of wheat innate immunity through comparative genomics and prioritized mutations in candidate genes for phenotypic assays. In parallel, we conducted a forward genetics screen by exposing our mutagenized wheat population to natural disease pressure in the field and identified mutants with either gain-of-resistance or compromised resistance to stripe rust. We are following up candidate mutations and employing mapping-by-sequencing to identify genetic basis for these phenotypes.