Genome-Wide Mutation Scanning By Exon Capture in Wheat

Mutagenesis using ethyl methane sulphonate (EMS) is a common method for increasing available genetic variation in plants: the mutations created can be used for both forward and reverse genetics. The latter approach is particularly powerful in polyploid species such as wheat as genetic redundancy limits the use of forward genetics but also allows very high mutation rates. We and our collaborators have developed a high-throughput mutation screening approach in wheat using exome capture and next-generation sequencing. This has identified a very large number of point mutations in the majority of wheat genes within an EMS-mutagenized population of wheat cv. Cadenza that provides a publicly-available resource for functional genomic and crop improvement. In this work, we have analyzed the exome capture data for variation in read coverage at the scaffold and exon level and have identified widespread deletions, including the loss of whole chromosome and chromosome arms. Large homozygous deletions were observed to be far less abundant in the M₂ DNA than heterozygous deletions, indicating that large deletions may affect transmission of gametes or viability of offspring. Data will be presented on the presence of such deletions in subsequent generations of the population.