Wheat Gluten, a Sticky Situation; A Historical Evaluation.

The incidence of celiac disease appears to have increased, leading to questions regarding potential changes across time in the composition of gluten (glutenin and gliadin). Have there been changes in the frequencies of gluten alleles in hard or soft-grained wheat (Triticum aestivum) that might make wheat a stronger trigger for celiac disease? Are potential changes a result of breeding for increased dough strength? One hundred twenty-four production cultivars from the Pacific Northwest (PNW) and elsewhere across the United States were collected. Cultivars date back to 1900 (one to 1800's). PNW soft-winter wheat cultivars were included as there has been no systematic selection pressure applied to increase dough strength in this wheat class. Plants were grown under greenhouse conditions as a randomized complete block with three replications. For gliadin genotyping, RNA was extracted from seeds 21 days post-anthesis then analyzed by high-throughput amplicon sequencing of a gliadin variable region. Grain was harvested at maturity. Microfluidic capillary electrophoresis was used to determine glutenin and gliadin composition in mature grain. Results from these analyses will show if the spectrum of gluten proteins has shifted over time in hard and soft winter wheat and if the frequency of gliadin epitopes associated with celiac disease have increased over time due to selection for dough strength.