Celiac disease is the most common food-induced enteropathy in humans, with a prevalence of approximately 1% worldwide. It is induced by digestion-resistant, proline- and glutamine-rich seed storage proteins, collectively referred to as “gluten,” found in wheat (Triticum aestivum). Related prolamins are present in barley (Hordeum vulgare) and rye (Secale cereale). The incidence of both celiac disease and a related condition called non-celiac gluten sensitivity (NCGS) is increasing. This has prompted efforts to identify methods of lowering gluten in wheat, one of the most important cereal crops. Here, we used bulked segregant RNA-seq (BSR-seq) and map-based cloning to identify the genetic lesion underlying a recessive, low prolamin mutation (lys3a) in diploid barley. We confirmed the mutant identity by complementing the lys3a mutant with a transgenic copy of the wild-type barley gene and then used targeting induced local lesions in genomes (TILLING) to identify induced single-nucleotide polymorphisms (SNPs) in the three homoeologs of the corresponding wheat gene. Combining inactivating mutations in the three subgenomes of hexaploid bread wheat in a single wheat line lowered gliadin and low molecular weight glutenin accumulation by 50-60% and increased free and protein-bound lysine by 33%.
