Investigation of Differential Expression of Alpha-Gliadin Genes with Variable Immunogenic Epitopes in Hexa- and Tetraploid Wheat Cultivars Suggests Some Have Lower Immunogenicity

• Published in: Plant molecular biology reporter 2023-03, Vol.41 (1), p.134-144
• Main Authors: Arora, Jaskaran Kaur, Kaur, Satveer, Yadav, Inderjit, Kaur, Satinder, Garg, Monika, Chhuneja, Parveen
• Format: Article
• Language: English
• Subjects: Allergic reactions; Annotations; Autoimmune diseases; Bioinformatics; Biomedical and Life Sciences; Celiac disease; Chromosomes; Cultivars; Epitopes; Food allergies; Gene expression; Genes; Genotypes; Gliadin; Gluten; Immunogenicity; Inflammatory diseases; Intestine; Life Sciences; Lymphocytes T; Metabolomics; Original Article; Phylogeny; Plant Breeding/Biotechnology; Plant Sciences; Proteins; Proteomics; Small intestine; Triticum; Wheat
• ISSN: 0735-9640; 1572-9818
• DOI: 10.1007/s11105-022-01356-4

Celiac disease (CD) is an inflammatory disorder that damages the lining of the small intestine. The allergic reaction to the alpha (α)-gliadin class of gluten proteins present in wheat leads to this autoimmune response. α-Gliadin proteins of the wheat gluten form a multigene family with different number and type of CD-eliciting epitopes. The present experiment was planned to study the relative variations in the α-gliadin proteins and their CD-eliciting epitopes in the eight Triticum genotypes including three tetraploid (PDW 274, PBW34, Bansi162) and five hexaploid cultivars (C591, C273, K78, PBW 54, and 9D). Reference-based annotation followed by detailed analysis of unassigned gliadins for domain organization, epitope frequency, and phylogeny relatedness; out of total 43 gliadin genes, 8 were assigned to chromosome 6A, 26 to chromosome 6B, and 9 to 6D. Relative expression analysis revealed that durum wheat genotypes have lower expression of immunogenic epitopes than hexaploid. Chromosome 6A-specific T-cell stimulatory epitope combination was highyly expressed in all the cultivars followed by those from chromosome 6D and least from 6B. The lower proportion of T-cell stimulatory epitopes in PBW54 was due to the lower expression of the 6A encoded epitopic combination that was compensated by the relatively higher expression of non-immunogenic variants forms of 6B. This study is the initial step towards developing wheat that is less immunogenic for celiac disease patients.