Allelic variation at high-molecular-weight glutenin subunit Loci, Glu-A1, Glu-B1 and Glu-D1, in Japanese and Chinese hexaploid wheats

Variation in the electrophoretic banding patterns of high-molecular-weight (HMW) glutenin subunits of 274hexaploid wheat (Triticum aestivum) varieties from China was examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and 27 different major HMW glutenin subunits were identified. Each variety contained three to five subunits and 29different glutenin subunit patterns were observed in274 Chinese hexaploid wheats. Seventeen alleles were identified based on the comparison of subunits mobility with that previously identified in a set of standard hexaploid wheats. The Chinese hexaploid wheats exhibited allelic variation in HMW glutenin subunit composition and the variation differed from that of Japanese and hexaploid wheats of other countries. This revised version was published online in July 2006 with corrections to the Cover Date.     

Introduction to bread wheat (Triticum aestivum L.) and assessment for bread-making quality of alleles from T. boeoticum Boiss. ssp. thaoudar at Glu-A1 encoding two high-molecular-weight subunits of glutenin

Two alleles, Glu-A1r encoding high-molecular-weight (HMW) glutenin subunits 39+40 and Glu-A1s encoding HMW glutenin subunits 41+42, were introgressed to bread wheat (Triticum aestivum L.) cv. Sicco from two accessions of T. boeoticum Boiss. ssp. thaoudar (A genome species, 2n=2x=14). Alleles at Glu-A1 in current commercial bread wheats encode zero or one subunit, and alleles at the homoeoloci Glu-B1 and Glu-D1 encode a maximum of two subunits; hence the maximum number of subunits found in commercial wheats is five, whereas the lines incorporating Glu-A1r and Glu-A1s carry six. Using near-isogenic lines, the current results demonstrated that the introduction of Glu-A1r resulted in diminished dough stickiness and improved stability during mixing compared with Glu-A1a encoding subunit 1, and a small improvement in gluten strength as shown by the SDS- sedimentation test. The introduction of Glu-A1a also resulted in a small improvement in gluten strength predicted by the SDS-sedimentation test. Thus the alleles are of potential value in breeding programmes designed to improve bread-making quality.     

The HMW glutenin suhunit composition of bread-wheat varieties bred in Pakistan

A total of 50 bread-wheat varieties bred in Pakistan were characterized for the composition of the high-molecular-weight glutenin subunit (HMW-GS). The glutenin subunits, as revealed by sodium dodecyl-sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) were numbered according to Payne's numbering system and, varieties were accordingly assigned theoretical quality scores. All varieties were found to possess either subunit 1 or 2* coded by the A genome. Subunits 17+18 and 7 + 9 of the B genome and 5+10 of the D genome were predominantly found in this set of varieties. The frequency of the appearance of Glu-l alleles in the varieties was different from that seen in other countries, especially in terms of the absence of the ‘null’ form of the A genome and the presence of novel subunits at the Glu-Bl and Glu-Dl loci. The compositions of HMW-GS were generally of good quality, with more than 50% of the varieties achieving quality scores of 9–10 with a high (8.6) average score. The results in this study indicate that wheat varieties bred in Pakistan have a narrow genetic base in terms of HMW glutenin subunits. It appears that the breeders have been selecting wheat genotypes of glutenin subunits associated with good quality without knowing the actual composition of these subunits. The database established on the basis of these results is useful for wheat-improvement programmes aimed at varietal identification and breeding for good quality parameters.     

Rapid screening of selected European winter wheat varieties and segregating populations for the Glu-D1d allele using PCR

Forty-two winter wheat varieties and 193 F₂ and BC₁F₂ seeds were screened for Glu-D1d allele encoding the HMW glutenin subunits 5 + 10 using polymerase chain reaction (PCR). The segregating populations originated from crosses involving wheat parents with good and poor bread-making quality. A clear PCR product of 450 bp, representing 1Dx5 of the Glu-D1d allele was identified in 24 varieties and 111 hybrid seeds. Four different Glu-D1 alleles: a (2 + 12), b (3 + 12), c (4 + 12) and d (5 + 10) were detected using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Only genotypes possessing Glu-D1d gave a positive PCR signal, hexaploid triticale and 4 × wheat lacking Glu-D1 locus gave a negative signal. The efficiency of PCR selection for bread-making quality in early generations using half seed is discussed.     

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.     

甘肃春小麦资源HMW-GS组成研究

应用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)方法,分析了176份甘肃省春小麦资源的高分子量麦谷蛋白亚基(HMW-GS)组成.结果表明,甘肃省春小麦资源的亚基组成较丰富,共检测到18种亚基变异类型和28种亚基组合类型.地方品种的亚基组合类型较少而且以Null、7+8、2+12为主,育成品种的亚基变异类型比地方品种丰富,以1、7+8、2+12 3种变异类型的出现频率为最高.供试材料HMW.GS的品质评分在4～10分之间,平均得分7.2,所筛选出的一批含优质亚基组合的材料可供育种工作者利用.     

Variation of high-molecular-weight glutenin subunits amongst cultivars of Triticum turgidum L. from Portugal

Summary Variation in high-molecular-weight (HMW) glutenin subunit composition amongst 63 varieties of Triticum turgidum L. from Portugal was investigated using SDS-PAGE. A total of thirteen Glu-A1 and Glu-B1 alleles were identified, and three of them were found to be different from those previously described in the literature. A number of the tetraploid wheats examined contained subunits known to have a beneficial effect of the bread-making properties of T.aestivum. Camara, a tetraploid wheat cultivar carrying a 1D/1B chromosomal substitution, is proposed as a bridge for the transfer of Glu-D1 alleles and of other protein fractions controlled by the 1D chromosomes (Gli-D1 locus) from hexaploid to tetraploid wheat.     

Introduction of high molecular weight glutenin subunits 5 + 10 for the improvement of the bread-making quality of hexaploid triticale

In an earlier study, chromosome 1D of the hexaploid breadwheat cultivar ‘Chinese Spring’ was introduced into hexaploid triticale to improve its bread‐making quality. That specific chromosome, 1D, carried the a allele at the Glu‐D1 locus coding for high molecular weight (HMW) glutenin subunits 2 + 12, and since subunits 2 + 12 are associated with poor bread‐making quality in wheat, in the present study hexaploid 1D substitution triticale was crossed with octoploid triticale with the d allele at the Glu‐D1 locus encoding HMW glutenin subunits 5 + 10. Following backcrosses to different triticale varieties, 1D substitution lines were established that had Glu‐D1 allele a or d in an otherwise genetically similar background, and the influence of these two different alleles on bread‐making quality of hexaploid triticale was compared. The agronomic performance of 76 selected lines was evaluated in a field trial. The Zeleny sedimentation value was determined as a parameter for bread‐making quality, and related to the presence of chromosome 1D, the different glutenin alleles and the nature of the substitution. The presence of chromosome 1D had a significant and positive effect on the Zeleny sedimentation value, but the difference between the two glutenin alleles 2 + 12 and 5 + 10 was not as obvious as in wheat. Owing to its high cytological stability and minimal effect on agronomic performance, substitution 1D(1A) appears to be the most desirable one to use in triticale breeding.     

Transfer of the Glu-D1 Gene from Chromosome 1D to Chromosome 1A in Hexaploid Triticale

To complement previously developed recombinant chromosomes 1R.1D, two series of translocations involving the Glu-D1 gene from chromosome ID to chromosome 1A were produced in hexaploid triticale. These series involve seven independent transfers of allele d encoding for high molecular weight glutenin subunits 5+10 and ten independent transfers involving allele a encoding for HMW glutenin subunits 2 + 12. The frequency of homoeologous recombination between chromosomes 1A and 1D was within the range observed for pairs of homologues in wheat, supporting earlier observations that homoeologous recombination in triticale is frequent. Recombined chromosomes 1A.1D can be used to introduce the Glu-D1 gene to durum wheats, and to manipulate the dosage of Glu-D1 in hexaploid triticale and bread wheat.     

High molecular weight glutenin subunit composition of Chinese bread wheats

Summary The endosperm storage proteins of 205 Chinese bread wheat cultivars and advanced lines were fractionated by SDS-PAGE to determine their high molecular weight (HMW) glutenin subunit composition. Seventeen alleles were identified: three at Glu-A1, eight at Glu-B1, and six at Glu-D1. The most common alleles were Null, 1, 7+8, 7+9, and 2+12. The results indicate that wheats from different regions differ in their frequencies of HMW glutenin subunits, however, none of the subunits could be related to specific environments. The glutenin quality scores of Chinese wheats ranged from 3 to 10, with an average of 6.7. Increasing quality scores have implications in improving steam-bread making quality for Chinese consumers. On the basis of HMW glutenin subunit composition, Chinese wheats are close to European wheats, especially Italian wheats because several Italian introductions are widely distributed in the pedigrees of Chinese wheat.     

Genetic diversity of high-molecular-weight glutenin subunit compositions in landraces of hexaploid wheat from Japan

The high-molecular-weight (HMW) glutenin subunit composition of seed storage protein of 174 Japanese hexaploid wheat (Triticum aestivum) landraces have been examined by using sodium dodecyl sulfate polyacrylamide gel electrophoresis system. Twenty four different, major glutenin HMW subunits were identified, and each of the landraces contained three to five subunits and 17 different glutenin subunit patterns were observed for 13 alleles in the landraces. On the basis of HMW glutenin subunits composition, Japanese landraces showed a specific allelic variation, close to Japanese commercial wheats in HMW glutenin subunits, different from those in alien hexaploid wheats. Further, it could be concluded that all common glutenin alleles can be found in the 174 landraces originated from Japan. The variation detected in the glutenin subunits is useful for variety identification, has a bearing on our understanding of hexaploid wheat genetic resource evolution in Japan, and raises questions concerning the nature of this genetic variation. This revised version was published online in July 2006 with corrections to the Cover Date.     

高分子量麦谷蛋白亚基的SDS-PAGE图谱在小麦品质研究中的应用

本实验应用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE),分析了河南72个小麦品种(品系)的高分子量(HMW)麦谷蛋白亚基组成,并测定其蛋白质含量、面筋含量、沉淀值、流变学特性和面包烘烤品质。发现含有 Glu—1 D 5+10亚基的品种一般有好的面粉品质和面包烘烤品质,含有 Glu—1 B 7+8或 Glu—1 A 2~*或 Glu—1 B 7亚基的品种有     

Allelic variation in high-molecular-weight glutenin subunit Loci of Glu-1 in Japanese common wheats

Seed storage proteins of 131 Japanese Norin wheat (Triticum aestivum) varieties were fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis to determine allelic make-up in varieties at each of three loci that control high-molecular-weight (HMW) glutenin subunits. Three alleles were identified at the Glu-A1 locus, six at the Glu-B1 locus and five at the Glu-D1 locus. Twenty-four different, major glutenin HMW subunits were identified and each contained three to five subunits and seventeen different glutenin subunit patterns were observed for 19 subunits in the 131 Japanese Norin varieties. Fourteen alleles were identified by comparison of subunit mobility with that previously found in hexaploid wheat. Japanese Norin varieties showed a specific pattern of allelic variation in glutenin HMW subunits, different from that of Chinese and other country common wheats in allelic frequency at Glu-1 loci. This revised version was published online in July 2006 with corrections to the Cover Date.     

Deficiency of individual high molecular weight glutenin subunits affords flexibility in breeding strategies for bread-making quality in wheat Triticum aestivum L.

High-molecular-weight (HMW) glutenin subunits in wheat Triticumaestivum L., allelic variation for which affects bread-making quality, areencoded by Glu-1 homoeoloci located on the homoeologous group1 chromosomes. Many alleles at Glu-B1 and Glu-D1 producetwo subunits, an x-type of low electrophoretic mobility in polyacrylamidegels, and a y-type of high mobility. In the current study, a combination ofnear isogenic lines of cultivar `Sicco' has been used to characterise theeffect upon quality of the absence of individual subunits 7 (Glu-B1x-type), 12 (Glu-D1 y-type) and, assuming an additive model ofsubunit action, 2 (Glu-D1 x-type). Absence of subunit 7 gave amoderate reduction in SDS-sedimentation volume, indicating its associationwith lower gluten strength (confirmed by Farinogram and Extensogramstudies), yet, from a full mixing input bake, a moderate increase in loafvolume and a considerable improvement in loaf score (an overall evaluationof loaf quality). Absence of subunit 12 gave a slightly larger reduction inSDS-volume, yet no change in loaf volume or score. Absence of bothsubunits 2+12 gave a larger reduction again in SDS-volume, a moderatereduction in loaf volume and a large reduction in loaf score. Absence ofsubunit 2 alone is therefore predicted to reduce SDS-volume, loaf volumeand score such that loss of this x-type subunit would lead to larger changesin quality parameters than loss of y-type subunit 12. A general conclusionof the study is that, while deficiency for HMW glutenin subunits generallyleads to reduced gluten strength and viscoelasticity, the resultantintermediate gluten strength may on occasions lead to improvements in loafperformance in situations where the base gluten strength is high. Theremay, then, be contexts in breeding programmes where selection fordeficiency would be a possible strategy for improving bread-making quality,adding to the flexibility available to the breeder. Somewhat unexpectedly,additional analysis found that, in the genetic background of cultivar `Sicco'used in this study, subunits 7+8 at Glu-B1 were indistinguishablefrom their allelic counterparts subunits 7+9 for virtually all characters, andthat subunits 2+12 at Glu-D1, while inferior in performance formixing properties compared to subunits 5+10, were associated with goodloaf characteristics.     

Quality evaluation of D-zone omega gliadins in wheat

One-hundred and eighty-one wheat cultivars and breeding lines of diverse origin, together with 409 and 540 Swedish spring and winter wheat breeding lines, respectively, were analysed by electrophoretical methods for D-zone omega gliadins. Correlations were calculated between the D-zone omega gliadin and high-molecular-weight (HMW) glutenin subunit patterns, with Zeleny volume or specific Zeleny volume. The results showed that simultaneous screening of D-zone omega gliadins and HMW subunits of glutenin was possible, and that the variation in Zeleny volume was attributed approximately equally between these protein groups. Both protein patterns can be used as parameters when breeding for bread-making quality. Positive relationships were found between gliadins d7 and d2 d4, and the specific Zeleny volume. Gliadins d11 d12 and the null allele of chromosome IB showed indications of negative relationships. Common D-zone omega gliadin patterns in the Swedish winter-wheat breeding lines were d2d4 and d11 d12 (67% of the lines), and the null allele of chromosome IB and d11 d12 (in 25%). Greater variation was documented in the spring breeding lines than in the winter lines.     

在一对面包小麦杂交后代中Glu—B1控制的麦谷蛋白亚基17 18对烘烤品质的影响

将两个优质面包小麦品种安农8455(含Glu-Bl控制的7 8亚基)和Yecora Rojo(含Glu-Bl控制的17 18亚基)进行杂交,测定了其F_3代重组株系的高分子量麦谷蛋白亚基组成、SDS沉降值、伯尔辛克值、蛋白质含量和籽粒产量以及收获指数。利用方差分析、协方差分析和回归分析说明了,17 18亚基对面包品质的作用明显优于7 8亚基,两者的品质差异随着蛋白质含量的增加而增大。文中讨论了17 18亚基在培育较高面包品质潜力的小麦品种中的利用价值。     

应用灰色关联分析法综合评估小麦高分子量麦谷蛋白亚基的研究

本文利用在河南种植的72个小麦品种面包烘烤品质指标的试验资料,借助于灰色关联分析法,对11种高分子量麦谷蛋白亚基进行了综合评估.结果表明:等权关联度与加权关联度分析结果基本吻合;Glu-1D5+10亚基对小麦烘烤品质的贡献最大;各亚基的关联度排序与其实际烘焙功能相一致.同时认为,采用多个品质指标的综合评估结果制定HMW麦谷蛋白亚基的评分系统,可能比用单一指标制定的评分方法更可靠.     

Genetic variation of wheat glutenin subunits between landraces and varieties and their contributions to wheat quality improvement in China

Glutenin, one of major factors effecting bread-making quality, is comprised of a mixture of polymers, viz. high-molecular-weight glutenin subunits (HMW-GSs) and low-molecular-weight glutenin subunits (LMW-GSs). Understanding variation among these glutenin subunits can help breeders determine allelic effects on specific quality traits and to use them as genetic markers. The HMW-GS and LMW-GS compositions of 390 landraces and 225 released varieties were analyzed by SDS–PAGE, and some quality traits, including Zeleny sedimentation volume, dough development time, stability time and strengths, were evaluated. The results indicated that 17 and 13 HMW-GSs were present in landraces and released varieties, respectively. For LMW-GS (Glu-A3 and Glu-B3 loci), 12 alleles were found in both landraces and released varieties. Total allelic richness at glutenin loci in landraces was higher, but the genetic dispersion index was lower than in released varieties. Two new subunit combinations 6 + 16 and 7 + 22, and some rare subunits 6 + 9*, 23 + 22, 6* + 8, 7 and 8, were identified in landraces and released varieties. The Glu-D1 and Glu-B3 loci had significantly positive effects. Based on the comparison of the effect of each subunit on quality, it was concluded that subunits 1 at Glu-A1, 13 + 16, 17 + 18 and 6 + 16 at Glu-B1, 5 + 10 at Glu-D1, Glu-A3b at Glu-A3 and Glu-B3d at Glu-B3 contributed larger positive effects on bread-making quality than alternative alleles. From this study, genetic materials with strong gluten and good quality were identified in landraces that did not carry the 1BL.1RS translocation.     

Relationship between common wheat (Triticum aestivum L.) gluten proteins and dough rheological properties

This paper reports the correlation between the rheological properties of bread wheat dough and the types and quantities of endosperm proteins in 28 common wheat cultivars. Different methods were used to analyse the allelic composition of these cultivars and the relative quantities of the different proteins contributing to the gluten structure. Neither dough strength (W) nor tenacity/extensibility (P/L) correlated with allelic composition. Different wheats with the same allelic composition (i.e., with respect to glutenins) showed different rheological properties. The glutenins were the most influential components of W and P/L, especially the high molecular weight (HMW) glutenin subunits and in particular the type x form. These proteins seem to increase W and are the main constituents of the gluten network. The gliadins and low molecular weight (LMW) glutenin subunits appear to act as a “solvent”, and thus modify the rheological properties of the dough by either interfering with the polymerisation of the HMW glutenin subunits, or by altering the relative amounts of the different types of glutenin available. Thus, the protein subunits coded for by the alleles Glu-B1x7 and Glu-D1x5 stabilised the gluten network, whereas those coded for by Glu-B1x17 and Glu-D1x2 had the opposite effect. Dough properties therefore appear to depend on the glutenin/gliadins balance, and on the ratio of the type x and type y HMW proteins. The influence of external factors seems to depend on the allelic composition of each cultivar.     

小麦品质的麦谷蛋白亚基评定标准研究

测定了233份小麦面粉样品的高分子量谷蛋白亚基(HMW-GS)含量、Zeleny-沉降值和谷蛋白大聚体(GMP)含量,并根据SDS-PAGE结果计算了其Payne亚基品质评分.结果表明,不同HMW-GS含量差异显著,不同HMW-GS所对应品种的HMW谷蛋白总量、沉降值、GMP含量、Payne品质评分平均值也存在显著差异,说明不同亚基对品质的影响存在显著差异.HMW谷