Allelic variation and genetic diversity of low-molecular-weight glutenin subunit- and α/β-gliadin encoding genes in tetraploid wheat

Allelic variations in storage-protein genes play a significant role in determining the properties of wheat flour. This study aimed to investigate allelic diversity in gene blocks encoding seed storage proteins in tetraploid wheat, specifically α/β-gliadin and low-molecular-weight glutenin subunits (LMW-GS). DNA was extracted from 90 rain-fed durum wheat genotypes, followed by a polymerase chain reaction (PCR) with 12 specific primers targeting Gli-A2, Gli-B2, Glu-A3, and Glu-B3 gene loci. The PCR products were then analyzed on a 2% agarose gel. For the Gli-A2 gene block, three pairs of specific primer identified a total of 13 alleles, while the Gli-B2 gene block revealed two alleles using the gli-AS_2 primer. In the Glu-A3 gene block, six primer pairs detected 42 alleles, and the Glu-B3 gene block showed eight alleles using 2 primer pairs. In total, we identified 7 major alleles and 8 minor alleles at Gli-2 loci, and 12 major alleles and 38 minor alleles at Glu-3 loci. Different primers yielded varying banding patterns, with the highest alleles and banding pattern counts observed with Glu3A.1 primer. Genetic dissimilarities ranged from 0.030 (between G21 and G83) to 0.583 (between G4 and G51). Structure analysis categorized the durum wheat collection into five subpopulations. Results confirmed a substantial variation at the Gli-2 and Glu-3 loci in tetraploid wheat.