Identification of proteins that contribute to flour strength among elite breeding lines in a breeding program

Gluten, which is a protein aggregate specific to wheat, is crucial in determining the physical properties of wheat flour dough. The gluten is primarily composed of glutenin and gliadin, which are multigenic and comprise diverse proteoforms. Consequently, it is difficult to analyze the quality of gluten by genetic analysis alone. Here, comprehensive protein analysis of wheat cultivars/strains was performed using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) that allows proteoforms to be resolved by spot position. AlveoConsis-tograph deformation energy (Fb value) was used as a metric for the strength of the dough. Major proteins resolved by 2D-DIGE were identified by LC/MS/MS. We verified that the Glu-B1al allele significantly influences the physical properties of the dough. Next, excluding the influence of the Glu-B1al allele, we identified proteins that contribute to the physical properties of the dough. Two & gamma;-gliadins and five low molecular weight glutenins were identified. A positive correlation was observed between the spot volume ratio of & gamma;-gliadin and its corresponding Fb value. Thus, & gamma;-gliadin exists as multiple proteoforms, one of which may contribute to the physical properties of dough. Combining the proteins identified in this study will help breeders develop high quality flour.