title: Molecular diversity of α-gliadin expressed genes in genetically contrasted spelt (Triticum aestivumssp.spelta) accessions and comparison with bread wheat (T. aestivumssp.aestivum) and related diploidTriticumandAegilopsspecies.
abstract: The gluten proteins of cereals such as bread wheat (Triticum aestivumssp.aestivum) and spelt (T. aestivumssp.spelta) are responsible for celiac disease (CD). The α-gliadins constitute the most immunogenic class of gluten proteins as they include four main T-cell stimulatory epitopes that affect CD patients. Spelt has been less studied than bread wheat and could constitute a source of valuable diversity. The objective of this work was to study the genetic diversity of spelt α-gliadin transcripts and to compare it with those of bread wheat. Genotyping data from 85 spelt accessions obtained with 19 simple sequence repeat (SSR) markers were used to select 11 contrasted accessions, from which 446 full open reading frame α-gliadin genes were cloned and sequenced, which revealed a high allelic diversity. High variations among the accessions were highlighted, in terms of the proportion of α-gliadin sequences from each of the three genomes (A, B and D), and their composition in the four T-cell stimulatory epitopes. An accession from Tajikistan stood out, having a particularly high proportion of α-gliadins from the B genome and a low immunogenic content. Even if no clear separation between spelt and bread wheat sequences was shown, spelt α-gliadins displayed specific features concerning e.g. the frequencies of some amino acid substitutions. Given this observation and the variations in toxicity revealed in the spelt accessions in this study, the high genetic diversity held in spelt germplasm collections could be a valuable resource in the development of safer varieties for CD patients.
authors.affiliation: Centre wallon de Recherches agronomiques (CRA-W), Département Sciences du vivant, Chaussée de Charleroi, 234, 5030 Gembloux, Belgium ; Earth and Life Institute - Agronomy, Université catholique de Louvain (UCL), Croix du Sud, 2 bte L7.05.11, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Benjamin
authors.identifier: 0000-0002-4545-5688
authors.initials: B
authors.lastname: Dubois
authors.affiliation: Earth and Life Institute - Agronomy, Université catholique de Louvain (UCL), Croix du Sud, 2 bte L7.05.11, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Bertin
authors.affiliation: Centre wallon de Recherches agronomiques (CRA-W), Département Sciences du vivant, Chaussée de Charleroi, 234, 5030 Gembloux, Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: Mingeot
keywords: Celiac disease; Genetic diversity; Gluten; Spelt; α-gliadin