一种利用染色体显微切割和微克隆获得小麦基因探针的方法

利用染色体显微切割和微克隆技术对普通小麦钢８２－１２２（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ ２ｎ＝４２）染色体长臂１Ｄ染色体进行切割和ＰＣＲ扩增，提出了高分子量麦谷蛋白（ＨＭＷ－ＧＳ１）１Ｄｘ５亚基基因片段，可为获得新基因特异性探针打下一定的基础。     

氮肥形态对不同HMW-GS类型春小麦高分子量谷蛋白聚合体积累的效应

以12个具有不同HMW-GS组成类型的春小麦为材料,在同一氮水平条件下研究不同形态氮肥对春小麦籽粒HMW谷蛋白聚合体的效应。结果表明,春小麦开花后10～15 d左右形成可溶性谷蛋白,先出现的是低分子量谷蛋白,接着是HMW谷蛋白聚合体。随籽粒生长谷蛋白积累水平呈上升趋势,花后25 d达最大值,但品种（品系）间的积累强度、最大     

一些小麦1B/1R易位系品质基因多样性分析

利用SDS-PAGE和A-A-PAGE分析了38份小麦1B/1R易位系Glu-1、Glu-3、Gli-1位点基因组成。结果表明,小麦1B/1R易位系中品质基因多样性降低,Glu-1、Glu-3编码的高、低分子量谷蛋白亚基种类减少,Glu-B1位点含有的优质亚基比例明显下降,Gli-1位点编码的醇溶蛋白比例增加,导致劣质。因此对于抗病品种品质改良要着重于改变其遗传组成尤其是Glu-1、Glu-3、Gli-1位点基因组成,尽可能打破Glu-3、Gli-1位点基因连锁关系,淘汰Glu-3位点基因的j,导入一些优良的品质基因。     

Correlation of glutenin macropolymer with viscoelastic properties during dough mixing

Although significant correlations exist for glutenin macropolymer (GMP) quantity and rheological properties/bread making quality of dough, little information about these links is available. The relationship between GMP contents measured by UV absorption method/RP-HPLC and dough viscoelastic properties determined by TA-XT2i texturometer from three wheat varieties (Xiaoyan6, Yumai56 and Zhengnong8805) during mixing was investigated. GMP contents of doughs decrease significantly (P<0.05) during mixing. During the initial mixing stage, amounts of the HMW-GS and LMW-GS and GMP decrease significantly (P<0.05). Their contents begin to increase beyond peak dough development time (DDT). This indicates that during further mixing after peak DDT some glutenin subunits are incorporated into GMP by repolymerization. The HMW/LMW-GS ratio has a significant effect on load-deformation properties (area, resistance and extensibility) of dough. The varieties behaved differently in relation to the contribution of their HMW-LMW-GS ratio to the rheological properties.     

Multiplex-PCR typing of high molecular weight glutenin alleles in wheat

In Australian commercial cultivars, each high molecular weight glutenin (Glu-1) homoeologous locus consists of one of two predominant alleles: Glu-A1a (subunit Ax1) or Glu-A1b (subunit Ax2*) at the GluA1 locus, Glu-B1b (Bx7 and By8 subunits) or Glu-B1i (Bx17 and By18 subunits) at the Glu-B1 locus, and Glu-D1d (Dx5 and Dy10 subunits) or Glu-D1a (Dx2 and Dy12 subunits) at the Glu-D1 locus. PCR-based assays have been developed in this study to discriminate between these common alleles at each locus. Primers specific for the Glu-A1 Ax2* gene give a single fragment of 1319 bp only in the presence of this gene. Primers targeting the Glu-B1 locus resulted in a co-dominant marker for which the Bx7 genotype produced two fragments (630 bp and 766 bp) and the Bx17 genotype a single fragment (669 bp). The third pair of primers was specific for the Dx5 gene and resulted in a single band of 478 bp. A multiplexed PCR assay was established which permitted the discrimination of the major HMW glutenins in a single PCR reaction and agarose gel assay. As the HMW glutenin composition of a wheat line is extremely important in determining the functional properties of wheat gluten, these markers are useful for the purposes of marker-assisted breeding. These markers may also be useful for the purpose of DNA-based identification of wheat varieties. This revised version was published online in July 2006 with corrections to the Cover Date.     

Molecular structure of a novel y-type HMW glutenin subunit gene present in Triticum tauschii

An unusually small y-type high molecular weight (HMW) glutenin subunit gene from Triticum tauschii was sequenced. This gene, encoded at the Glu-D^t1 locus was designated 12.4^t and is the smallest HMW glutenin subunit gene described so far in Triticum species. Oligonucleotide primers based on published sequences of HMW glutenin genes were designed to amplify the encoding region and the central repetitive domain of the gene, which produced fragments of 1.4 and 0.85 kb, respectively. PCR products were cloned and sequenced. The derived amino acid sequence was compared with the amino acid sequences of the HMW glutenin subunits Dy12^t, from T. tauschii, and subunits Dy10 and Dy12 of T. aestivum. The amino acid sequence deduced from the nucleotide sequence demonstrated that deletions of hexapeptides and nonapeptides were responsible for the reduction in the size of this HMW glutenin subunit. The estimated molecular weight of the Dy12.4^t subunit, calculated on the basis of the deduced amino acid sequence, was 45,228 Daltons. There were also single amino acid differences in the N-, C-terminal and central repetitive domains of this gene in comparison to the three other y-type subunits encoded at the Glu-D1 locus. The Dy12.4^t subunit showed the highest similarity to the Dy12 subunit present in the hexaploid wheat Chinese Spring.     

Additive and epistatic effects of allelic variation at the high molecular weight glutenin subunit loci in determining the bread-making quality of breeding lines of wheat

Summary The relation has been studied between the high molecular weight glutenin (HMWg) subunit alleles and the bread-making quality of 226 lines of winter wheat (T. aestivum L.), grown in The Netherlands. The lines represented a wide range of genetic backgrounds, and had not been selected for quality, in contrast to the established varieties used by other authors.The variation in HMWg subunit genotypes accounted for about 20% of the total variation in loaf volume among the lines. Most important was the allelic variation at the Glu-D1 locus. The Glu-D1 allele encoding the subunits 5+10 was superior to its allelic counterpart, encoding 2+12. The difference in average of loaf volume between groups of lines containing 5+10 or 2+12 was negatively related with protein content of the flours. When protein content was below 9.2%, no effect of allelic variation at the Glu-D1 locus was present. Epistatic effects between the Glu-I loci also contributed to the variation in loaf volume of the lines: i.e. the effect of allelic variation at Glu-A1 and Glu-B1 depended on the allele present at the Glu-D1. The contribution of the epistatic effects was about half the contribution of the additive effects, and should therefore be included in predictive models for bread-making quality.     

Genetic diversity of HMW glutenin subunit in Chinese common wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) landraces from Hubei province

The high molecular weight (HMW) glutenin subunit composition of 111 common landraces of bread wheat collected from Hubei province, China has been determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Ninety six of the accessions were homogeneous for HMW glutenin subunit composition and 15 were heterogeneous. For the Glu-1 loci, 16 alleles were detected, 3 at the Glu-A1locus, 9 at the Glu-B1and 4 at the Glu-D1. Three novel alleles were identified, two at the Glu-B1 and one at the Glu-D1locus. Combination of these 16 alleles resulted in 14 different HMW subunit patterns. The distribution of HMW glutenin subunit alleles in a subset of 105 of the 111 accessions representing six populations was assessed both at the individual population and whole population levels. The results demonstrated that the distribution of allelic patterns varied among populations. Taken together, 62.5% of the alleles detected were considered to be rare alleles while the Glu-A1c (null), Glu-B1b (1Bx7 + 1By8) and Glu-D1a (1Dx2 + 1Dy12) alleles were found most frequently in the six populations. The subset exhibited relatively high genetic diversity (A = 5.33, P = 1.00, Ae = 1.352 and He = 0.238) with 81.5% of the diversity being within populations and 18.5% between populations.     

小麦蛋白质含量和优质亚基遗传

研究了小麦子粒蛋白质含量和优质高分子量麦谷蛋白亚基对小麦品质的影响及其互作关系。结果表明，控制蛋白质含量的基因作用主要是以加性效应为主，也存在非加性效应，F1的蛋白质含量与双亲的蛋白质含量的平均值高度相关，蛋白质含量的一般配合力方差大于特殊配合力方差，F2子粒蛋白质含量的分离呈正态分布。在优质育种亲本选配上，一般配合力比特殊配合力更重要一些。普通小麦品种高分子量麦谷蛋白亚基受遗传控制，不受环境影响，具有品种特性；其在F1中呈共显性和倾母遗传现象，在F2中遗传行为遵从孟德尔的基因独立分配和自由组合规律。在小麦品质改良中既要重视蛋白质的含量，更应重视蛋白质的质量，即数量和质量改良途径并重。