Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: wheat breeding may have contributed to increased prevalence of celiac disease

Abstract

Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides can be presented by antigen presenting cells to gluten-sensitive T-cell lymphocytes leading to CD. During the last decades, a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness and to improved diagnostic techniques, but increased wheat and gluten consumption is also considered a major cause. To analyze whether wheat breeding contributed to the increase of the prevalence of CD, we have compared the genetic diversity of gluten proteins for the presence of two CD epitopes (Glia-α9 and Glia-α20) in 36 modern European wheat varieties and in 50 landraces representing the wheat varieties grown up to around a century ago. Glia-α9 is a major (immunodominant) epitope that is recognized by the majority of CD patients. The minor Glia-α20 was included as a technical reference. Overall, the presence of the Glia-α9 epitope was higher in the modern varieties, whereas the presence of the Glia-α20 epitope was lower, as compared to the landraces. This suggests that modern wheat breeding practices may have led to an increased exposure to CD epitopes. On the other hand, some modern varieties and landraces have been identified that have relatively low contents of both epitopes. Such selected lines may serve as a start to breed wheat for the introduction of ‘low CD toxic’ as a new breeding trait. Large-scale culture and consumption of such varieties would considerably aid in decreasing the prevalence of CD.

Gluten-free Diet - Tough Alley in Torrid Time

“…The process was accompanied by enrichment of gluten content in the wheat. In fact, multiple recent studies documented the increased CD epitopes along the process of gluten gene enrichment in the passage of ancient diploid to modern tetraploid and hexaploid wheat species [46,47,48,49]. Today, gluten proteins comprise gliadins and glutenins, which are present in approximately equal amounts and form 80% of the total storage protein content in the wheat kernel.…”

“…Multiple recent studies documented the increased CD epitopes along the process of gluten gene enrichment in the passage of ancient diploid to modern tetraploid and hexaploid wheat species [46,47,49]. Once again, this is an additional gluten toxicity, adding to the actual torrid time for the GFD consumers.…”

The rise and fall of gluten!

“…This has contributed to a dramatic change in the genetic variety and possibly immunogenic qualities of wheat over time (7) . Currently, about 95 % of the wheat grown worldwide is bread wheat (Triticum aestivum), a hexaploid species which resulted from the spontaneous hybridisations between more ancient tetraploid (Emmer) and diploid species (Wild grass) and was then selected by farmers for its superior qualities and yields, such as higher number and bigger seeds (8) .…”

The Genetic Variability of Wheat Can Ensure Safe Products for Celiac Disease Patients?

“…Several current studies have shown that compared to current varieties, the percentage of old varieties and some landraces that have a lower CD-immunogenic potential is much greater [30,31,32], which in itself reveals the genetic potential of wheat for the discovery of new traits that enable the development of hypoallergenic varieties for celiac patients. The replacement of the unique technological properties of wheat gluten represents the major task of industry for providing high quality glutenfree foods, such as pasta, bread and baked products, in terms of structure, loss of starch during cooking, and optimal cooking time [33].…”