The aim of the study “In search of tetraploid wheat accessions reduced in celiac disease-related gluten epitopes” is the identification of accessions of durum wheat with the least amount of fractions (epitopes) that activate the adverse response of the human immune system in celiac disease and not only.
Durum wheat with a smaller amount of these fractions (epitopes) might help undiagnosed CD-patients (approximately 95% of all CD-patients) who are daily consuming CD-stimulating gluten proteins without realizing its effect on their health and well being.
Durnm wheat identified although not suitable for celiac subjects “may contribute to delay or even prevent the onset of CD and its symptom development in that part of the population that is genetically susceptible, especially in children 37 (van den Broeck et al. in press), because the quantity of consumed CD-epitopes is a major factor that may influence the clinical representation of CD, along with some other recognized factors such as the type of cow’s milk formulas, omission of breast feeding, and age at gluten introduction. “
The study analyzed the gluten of “103 tetraploid wheat accessions (obtained from the Dutch CGN genebank and from the French INRA collection) including landraces, old, modern, and domesticated accessions of various tetraploid species and subspecies from many geographic origins. Those accessions were typed for their level of T-cell stimulatory epitopes.” The study has highlighted the existence of “ 8 CGN and 6 INRA accessions with reduced epitope staining.”
…omissis “Tetraploid wheats contain less T-cell stimulatory a-gliadin epitopes than hexaploid bread wheat because of the absence of the D-genome. The highly immunodominant T-cell stimulating 33-mer is exclusively present in a-gliadins encoded by the D-genome (bread wheat). In addition, the levels of T-cell stimulatory epitopes have been shown to vary among varieties (van den Broeck et al. ). This opens possibilities to select for wheat varieties with significantly reduced a-gliadin epitope levels, aiming at direct use or to apply in breeding programs directed towards large-scale reduction or even total elimination of CD-stimulating gluten-elements from wheat.”
Note
From the study
“A landrace may be a mixture of genotypes, which evolved under the environmental conditions where they were grown because of natural selection and selection by the farmer. Tetraploid wheat can mix up with hexaploid bread wheat very easily under agricultural conditions and care should be taken if the tetraploid wheat should be maintained as a pure genotype. As a result, many commercial lots, currently sold as durum wheat, nearly always contain some hexaploid bread wheat.”
“Differences among wheat varieties in gluten proteins occur because of allelic variation (genotype) that determines the gluten protein composition. The approach we used in this study analyzes this genotypic variation by comparing the same amount of gluten protein per accession. Changes in gluten protein composition have been described, but are mainly expected if growth conditions are extreme (high or low temperature, dry or wet conditions). The varieties and accessions we have analyzed were grown under normal wheat growth conditions and therefore, their influence on the gluten protein composition is not expected.”
”The occurrence of different genotypes and even different ploidy levels in a single genebank accession is a complicating phenomenon for genebank managers to accurately characterize landraces. Many landraces often result from maintenance and selection practices by local farmers directed towards optimizations to local agronomic and food applications. As a consequence, genebank passport data turned out to be poor predictors of the real genetic composition of landrace accessions that may be mixtures of genotypes of tetraploid and even hexaploid wheat species.”
In search of tetraploid wheat accessions reduced in celiac disease-related gluten epitopes. Hetty van den Broeck et al.
www.rsc.org/molecularbiosystems. July 2010 DOI: 10.1039/c0mb00046a
Keywords:
durum wheat, less toxic wheat, immunogenicity of wheat, predisposition to celiac disease, more tolerable durum wheat varieties, gluten proteins