小麦高分子量麦谷蛋白亚基组成及其对小麦烘烤品质的影响

采用SDS-PAGE方法分析了386份CIMMYT小麦材料的高分子量麦谷蛋白亚基(HMW-GS)组成,并测定了其微量SDS沉降值,同时评估了各亚基对小麦烘烤品质的贡献.电泳结果发现,供试材料所包含的亚基种类和组合非常丰富,共有14条不同亚基和25种不同的亚基组合.A组染色体编码的HMW-GS有Null、Ax1和Ax2,其频率分别为79.50%、16.32%和4.15%;B组染色体编码的亚基按频率由高到低排序为Bx7、Bx7 By9、Bx7 By8、By22、Bx20、Bx14 By15、Bx6 By8,它们的频率分别为42.75%、21.24%、17.36%、13.47%、3.89%、1.04%、0.26%;D组染色体编码的亚基为Dx5 Dy10、Dx2 Dy12、Dx5 Dy12、Dx2 Dy10,其中Dx5 Dy10和Dx2 Dy12亚基为主要类型,频率分别为76.42%和22.00%,含有Dx5 Dy12或Dx2 Dy10亚基的材料非常少,含有Dx5 Dy12亚基的仅有4份,含有Dx2 Dy10亚基的仅有2份,但它们用于研究D染色体编码的等位亚基的遗传和对小麦烘烤品质的贡献将具有重要作用.亚基组合1(Null 5 10 7)出现的频率最高,为34.20%;其次是组合3(Null 5 10 7 9),其频率为11.40%;组合16～25仅分布在1～2份材料中.各亚基对沉降值的影响结果显示,各位点编码的等位基因变异对小麦烘烤品质影响显著.Glu-A1位点上的1亚基的作用显著大于2和Null亚基,2与Null亚基间的差异不显著.Glu-B1位点上的7 8和22亚基显著优于7 9,而7、20和7 9亚基间有差异,但差异不显著,同样,7 8和22亚基间有差异,但差异不显著.5 10和2 12亚基对品质贡献与前人研究一致,5 10亚基显著优于2 12亚基.自然界十分稀少的材料———拥有2 10和5 12亚基的材料的收集对评价Glu-D1位点单个亚基或亚基联合对小麦品质的影响具有十分重要的意义.图1表8参10

Composition of High Molecular Weight Glutenin Subunits and Effect on Wheat Baking Quality

The composition of high molecular weight glutenin subunits (HMW-GSs) of 386 wheat lines from CIMMYT by the SDS-PAGE was identified, the micro SDS sedimentation value was determined, and the effect of the HMW-GS on wheat baking quality was evaluated. The result of the electrophoresis showed that the allelic variations were very rich in these investigated wheat lines and the frequencies of the allelic subunits at each encoding locus were widely different. Totally, there were 14 different subunit bands and 25 types of subunit combinations. At Glu-A1, subunits Null, Ax1 and Ax2* were observed with the frequencies of 71.50%, 16.32% and 4.15%, respectively. Subunits Bx7, Bx7 By9, Bx7 By8, By22, Bx20, Bx14 By15 and Bx6 By8 were found at loci Glu-B1 with frequencies of 42.75%, 21.24%, 17.36%, 13.47%, 3.89%, 1.04% and 0.26%, respectively. At loci Glu-D1, subunit Dx5 Dy10, Dx2 Dy12, Dx5 Dy12 and Dx2 Dy10 were shown with frequencies 76.42%, 22.00%, 1.04% and 0.52%, respectively. The entries containing subunit pairs Dx5 Dy12 and Dx2 Dy10 were found, and they rarely occurred in wild genotypes and were very important for determining the effect of individual HMW subunit at loci Glu-D1 on baking quality of wheat. Also, allelic variation strongly affected the baking quality of wheat. For the HMW subunits encoded at loci Glu-A1, the contribution of subunit Ax1 was much better than that of Ax2* and Null, and the difference between the latter two was not significant. For that of loci Glu-B1, the contributions of Bx7 By8 and By22 were significantly better than those of the others. At loci Glu-D1, the differences between subunits Dx 5 Dy10 and Dx2 Dy12 were consistent with those reported previously, that is, the contribution of Dx5 Dy10 was greatly larger than that of Dx2 Dy12. Fig 1, Tab 8, Ref 10