Abstract:

High molecular weight glutenin subunits (HMW-GS) are wheat endosperm storage proteins, which play an important role in the viscoelastic properties of dough. They are encoded by genes (Glu-1) located on the long arms of the group 1 chromosomes of hexaploid wheat (Triticum aestivum L.). Each locus consists of two tightly linked genes, an x-type and a y-type, which encode the high Mr x-type and the low Mr y-type subunit, respectively. Although 1Ax1, 1Ax2*, 1Bx7+1By8, 1Bx7^OE+1By8, 1Bx14+1By15, 1Bx17+1By18, 1Bx13+1By16, and 1Dx5+1Dy10 are recognized correlating with good bread-making quality, the x-type and y-type subunit genes at the same locus are very difficult to be separated in breeding. Therefore, it is very difficult to confer a score value for a single subunit. In breeding near-isogenic-lines (NILs) for HMW-GS of Xiaoyan 54 (1Ax1, 1Bx14+1By15, 1Dx2+1Dy12), an introduced variety, Prinqual was used as the donor of 1Bx17+1By18. A novel recombinant line 012912 with 1Bx14+1By18 was obtained. The recombinant (1Bx14+1By18) can stably inherit from generation to generation. Except the substitution of 1By15 by 1By18, all of the glutenin subunits and gliadin components of 012912 are consistent with those of Xiaoyan 54. The expression level of 1By18 was more than that of 1By15 by 29%, but the total protein content of the line 012912 was more than that of Xiaoyan 54 only by 0.29%. The SDS sedimentation of line 012912 was more than that of Xiaoyan 54 by 2.5 mL, and the mixing time and mixing tolerance were better than Xiaoyan 54. The results indicate that 1By18 has stronger positive effect than 1By15 on processing quality.

Key words: Wheat, HMW-GS, Near isogenic line, SDS sedimentation, Mixograph