Effect of Allelic Variation and Expression Quantity at Glu-1 Loci on Size Distribution of Glutenin Polymer in Common Wheat

Abstract

Two sets of common wheat ( Triticum aestivum L.) lines were used in this study, including 23 spring wheat genotypes in Trial I and 21 winter wheat genotypes in Trial II. The size distribution of glutenin polymers was significantly affected by allelic variation and expression quantity of Glu-1 loci based on flour protein content, especially on total expression quantity of high-molecular-weight glutenin subunits (HMW-GS). In Trail I, when the expression of HMW-GS was in a low level, significantly ( P < 0.01) additive effects were observed at Glu-B1 and Glu-D1 loci on content of SDS-unextractable polymeric protein (UPP) and percent SDS-unextractable polymeric protein in total polymeric protein (%UPP). The contribution of individual glutenin subunit ranked as 7 OE+8* > 7+9 > 17+18 > 7+8 at Glu-B1 and 5+10 > 2+12 at Glu-D1. The %UPP in genotype with subunit combination of 5+10 was higher than that with subunit combination of 2+12. The quantity of HMW-GS was positively correlated with UPP ( r = 0.79–0.93, P < 0.01). In Trial II, when expression of HMW-GS was in a high level, significantly additive effect on %UPP was only observed at Glu-D1 ( P < 0.05). The contribution to %UPP of individual glutenin subunit was ranked as 5+10 > 2+12 or 4+12 at Glu-D1. The size distribution of polymers was not significantly different among subunit combinations. The quantity of HMW-GS was positively correlated with UPP ( r = 0.42–0.86, P < 0.05 or 0.01). In conclusion, gluten strength and end-use quality can be improved by selection of high quality subunits in combination with high expression in breeding programs.