Effects of glu-1 and glu-3 allelic variations on wheat glutenin macropolymer (GMP) content as revealed by size-exclusion high performance liquid chromatography (SE-HPLC)

Gluten macropolymers (GMPs), formed by seed storage proteins glutenins and gliadins through intermolecular disulfide bond, confer dough viscoelasticity and wheat processing quality . Glutenins consist of high and low molecular weight glutenin subunits (HMW-GS, LMW-GS) encoded by Glu-1 and Glu-3 loci, respectively. The allelic variations at both loci have important effects on GMP content and breadmaking quality. In this study, GMP extraction and size-exclusion high performance liquid chromatography (SE-HPLC) separation were optimized, and then applied to investigate the effects of Glu-1 and Glu-3 allelic variations on GMP content using different wheat genotypes, chromosome substitution lines and near-isogenic lines (NILs). The results showed that the optimized GMP extraction and SE-HPLC protocol could obtain a reproducible separation and reliable quantitation of GMP content with small samples. The allelic variations at Glu-1 and Glu-3 were closely related to GMP content. Particularly, Glu-D1d encoded 1Dx5+1Dy10 subunits, Glu-A3a and Glu-B3h encoded an abundant LMW-B subunit respectively had positive effects on GMP content and breadmaking quality. The introgress of HMW-GS and LMW-GS into bread wheat from related genomes could significantly increase GMP content, indicating that wheat related species has potential gene resources for breadmaking quality improvement. Our results demonstrated that SE -HPLC could serve as an effective tool for rapid separation and quantitation of GMPs and had potential application for gluten quality screening in the early generations during wheat quality improvement program.