Effects of HMW-GS at Glu-B1 locus on the polymerization of glutenin during grain development and on the secondary and micro-structures of gluten in wheat (Triticum aestivum L.)

• Glu-1Bi started to polymerize glutenin earlier than other alleles at Glu-B1 loci.
• HMW-GS affected the β-sheet content, α-helix/β-sheet ratio of gluten.
• HMW-GS alleles at Glu-B1 locus affected the gluten pore size distribution differently.
• UPP% was correlated with the secondary structure of gluten.

The viscoelastic properties of wheat dough are due mainly to the structure of gluten and interactions within the protein complex. We determined the effects of high-molecular-weight glutenin subunit (HMW-GS) on the polymerization of glutenin during grain development and on the secondary and micro-structures of gluten, using Xinong1718 and its four near-isogenic lines (NILs). The polymerization of glutenin was monitored based on the percentage of unextractable polymeric protein (%UPP). Xi1718-3 with the superior allele Bx17 + By18 exhibited a rapid increase in %UPP five days earlier than the other lines with variations at Glu-B1, thereby obtained the highest %UPP at maturity. The secondary structures, such as the proportion of β-sheets and the α-helix/β-sheet ratio differed significantly among the NILs. The micro-structure of gluten in NILs varied in terms of the pore size distribution and cross-linkage patterns. Significant correlations were found between %UPP with the β-sheet content and α-helix/β-sheet ratio, so these secondary structures could also be used as indicators of wheat flour quality.