Chromosomal control of wheat gliadin: analysis by reversed-phase high-performance liquid chromatography

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Abstract
Gliadin proteins of the hexaploid wheat variety ‘Chinese Spring’, and of its nullisomic-tetrasomic and ditelocentric aneuploid lines, were analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC). Reversed-phase separations were carried out at 70°C on C8 and C18 columns using a gradient of increasing acetonitrile concentration in the presence of 0.1% trifluoroacetic acid. Thirty-five components were separated and all were found to be controlled by genes on the short arms of group 1 and group 6 chromosomes (the complex Gli-1 and Gli-2 loci). Results indicated that gluten polypeptides elute as groups in order of increasing hydrophobicity in the following approximate order: (1) albumins plus globulins, (2) ω-gliadins, (3) high molecular weight (MW) glutenin subunits, (4) α-type gliadins, (5) low MW glutenin subunits, and (6) γ-gliadins. The three distinct protein types coded by genes at the complex Gli-I loci (ω-gliadins, γ-gliadins, and low MW glutenin subunits) thus have uniquely different surface hydrophobicities. Similarly, gene locations for hexaploid ‘Cheyenne’ gliadins and durum gliadin proteins in the varieties ‘Langdon’, ‘Edmore’, and ‘Kharkovskaya-5’ were determined through RP-HPLC analysis of aneuploid lines. All results confirm known locations of genes for gliadin proteins, and demonstrate that RP-HPLC is a powerful new tool for analysis of gliadins in breeding and genetic studies.