Exome Capture and TILLING in Tetraploid and Hexaploid Wheats

Targeting Induced Local Lesions in Genomes (TILLING) is a powerful technology for identification of mutations in any targeted gene. TILLING has been successfully used in wheat to identify mutations in individual genes. In this study, we employ exome capture and next generation sequencing technologies to extend TILLING approaches to the genomic scale and offer functional genomic tools in wheat, specifically, for protein-coding sequences. As a first part of the project, we assembled a reference dataset of 82,511 annotated wheat genes from a high quality tetraploid wheat transcriptome and hexaploid wheat studies. Using Nimblegen’s exome capture platform together with modern robotics, we are re-sequencing TILLING populations of tetraploid pasta wheat and hexaploid bread wheat. In each sequenced line, we are identifying mutations in our reference genes and performing computational prediction of their effect on protein function. We are incorporating wheat chromosome arms survey sequences to predict gene models, identify homoeologs and anchor mutations. Using this information, we are building a publicly available database of wheat mutants linked to a seed repository that will be used by researchers and wheat breeders to identify and request lines with induced alleles of interest. The long-term goal of this project is to provide novel sources of genetic variation in wheat that will assist basic research and production of improved wheat products.