Cereal Chem. 71:238-242 | VIEW
Acid-Polyacrylamide Gel Electrophoresis of Wheat Glutenins: A New Tool for the Separation of High and Low Molecular Weight Subunits.
M. H. Morel. Copyright 1994 by the American Association of Cereal Chemists, Inc.
After sequential extraction of gliadins with 50% isopropanol, glutenins were extracted with the same solvent containing dithioerythritol and then alkylated with 4-vinylpyridine. Glutenin subunits were then resolved in a native polyacrylamide gel electrophoresis system buffered by acetic acid (acid-PAGE), which contained 2M urea to maintain protein solubility during migration. By two-dimensional electrophoresis (acid-PAGE times sodium dodecyl sulfate [SDS] PAGE) high molecular weight glutenin subunits (HMW- GS) were identified at the top of the acid-PAGE pattern in contrast to low molecular weight glutenin subunits (LMW-GS) that moved further. Twenty cultivars of known HMW-GS compositions in SDS-PAGE were analyzed by acid-PAGE. Most HMW-GS were well resolved; however, bands 2* and 7 tended to comigrate, whereas subunits 7 and 8 presented slight mobility variations according to cultivars. LMW-GS were also accurately resolved with acid-PAGE. In a set of intervarietal substitution lines of the cultivar Courtot, involving five donor cultivars, we identified three LMW-GS patterns controlled by Glu-3A, five by Glu-3B, and three by Glu-3D. Acid-PAGE bands characteristic of each Glu-3 loci allowed description of allelic variations of the donor cultivars, in contrast with SDS-PAGE patterns, where subunits controlled by Glu-B3 and Glu-D3 loci were frequently superimposed, making determination of the corresponding alleles difficult. The use of acid-PAGE to describe allelic variation among bread wheat cultivars at the three Glu-3 loci as an alternative to SDS-PAGE was discussed.