Molecular characterization of gliadins of Chinese Spring wheat in relation to celiac disease elicitors

Abstract

The wheat seed storage proteins gliadin and glutenin are encoded by multigenes.Gliadins are further classified into α-, γ-, δ-and ω-gliadins. Genes encoding α-gliadins belong to a large multigene family, whose members are located on the homoeologous group 6 chromosomes at the Gli-2 loci. Genes encoding other gliadins are located on the homoeologous group 1 chromosomes at the Gli-1 loci. Two-dimensional polyacrylamide gel electrophoresis (2-DE) was used to characterize and profile the gliadins. The gliadins in aneuploid Chinese Spring wheat lines were then compared in this study. Gliadin proteins separated into 70 spots after 2-DE and a total of 10, 10 and 16 spots were encoded on chromosomes 6A, 6B and 6D, respectively, which suggested that they were α-gliadins. Similarly, six, three and seven spots were encoded on chromosomes 1A, 1B and 1D, respectively, which indicated that they were γ-gliadins.Spots that could not be assigned to chromosomes were N-terminally sequenced and were all determined to be α-gliadins or γ-gliadins. The 2-DE profiles showed that specific α-gliadin spots assigned to chromosome 6D were lost in tetrasomic chromosome 2A lines. Furthermore, western blotting against the Glia-α9 peptide, an epitope for celiac disease (CD), suggested that α-gliadins harboring the CD epitope on chromosome 6D were absent in the tetrasomic chromosome 2A lines. Systematic 3 analysis of α-gliadins using 2-DE, quantitative RT-PCR and genomic PCR revealed that tetrasomic 2A lines carry deletion of a chromosome segment at the Gli-D2 locus. This structural alteration at the Gli-D2 locus may provide a genetic resource in breeding programs for the reduction of CD immunotoxicity.

Exploiting the reference genome sequence of hexaploid wheat: a proteomic study of flour proteins from the cultivar Chinese Spring

“…The complexity of gluten protein fractions in 2-DE has been the subject of a number of other studies. Kawaura et al (2018) resolved 70 spots by 2-DE from a gliadin fraction from Chinese Spring. Using aneuploid lines, they mapped 10 spots to chromosome 6A, 10 to 6B, and 16 to 6D, suggesting that these spots correspond to alpha gliadins.…”

“…The previous studies (Kawaura et al 2018;Wang et al 2017;Cho et al 2018) focused specifically on gliadin fractions from the flour. This reduced the numbers of proteins and made it possible to use a tighter pH range of 6-11 for the first-dimension separation.…”

Advances in the Biology of Seed and Vegetative Storage Proteins Based on Two-Dimensional Electrophoresis Coupled to Mass Spectrometry

“…However, the glutelin fraction and other allergen-related wheat proteins increased in low-gliadin lines by a compensation effect. Kawaura et al [ 209 ] obtained aneuploid wheat lines to reduce CD immunotoxicity in breeding programs. An analysis of 2-DE profiles disclosed that α-gliadins containing major CD epitopes were lost in tetrasomic lines.…”

Wheat research and breeding in the new era of a high-quality reference genome

“…of genes amplified in wheat and complemented the extensive analyses of the respective proteins in wheat [22] , including the recent studies by Altenbach et al [23] and Kawaura et al [24] . The prolamin family of genes encode the gliadin and glutenin proteins that accumulate in endosperm-protein bodies and provide a major source of nitrogen for the germinating embryo as well as nutrition for consumers of the grain.…”

“…Human health aspects of consuming wheat relating to celiac disease and allergic reactions [3,[22][23][24] could be addressed in detail at the genomics level with IWGSC RefSeq v1.0 [3] . The study of Juhász et al [3] established a new reference map for immunostimulatory wheat proteins as a basis for selecting wheat lines and developing diagnostics for products with more favorable consumer attributes.…”