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

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 7OE+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.

摘 要选用我国春播麦区23份(试验I)和北部冬麦区21份(试验II)品种(系), 研究了Glu-1位点等位变异及其亚基表达量对谷蛋白聚合体粒度分布的影响。结果表明, Glu-1位点等位变异及其亚基表达量显著影响谷蛋白聚合体的粒度分布, 且影响程度受蛋白质含量, 尤其是高分子量谷蛋白总量水平的影响。在高分子量谷蛋白总量较低时(试验I), Glu-B1和Glu-D1位点对不溶性谷蛋白大聚体含量(UPP)及其占聚合体蛋白总量的百分比(%UPP)的加性效应都达1%显著水平; Glu-B1和Glu-D1位点单个亚基对两者的贡献分别为7OE+8* >7+9 >17+18 >7+8和5+10 >2+12, 具有5+10亚基组合的%UPP显著高于具有2+12的亚基组合。高分子量谷蛋白的亚基表达量与UPP含量呈高度正相关, 相关系数为0.79∼0.93 (P < 0.01)。而在高分子量谷蛋白总量较高时(试验II), 仅Glu-D1位点对%UPP的加性效应达5%显著水平, 5+10亚基对%UPP的贡献显著高于2+12和4+12; 亚基组合间的聚合体粒度分布无显著差异。高分子量谷蛋白的亚基表达量与UPP含量的相关系数为0.42∼0.86 (P < 0.05或0.01)。结合高分子量谷蛋白表达量和优质亚基进行选择, 能有效提高不溶性谷蛋白大聚体的含量和相对比例, 有利于面筋强度和加工品质的进一步提高。