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.     

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.     

Relationship Between High Molecular Weight Glutenin Subunit Composition and Gluten Quality in Ethiopian-grown Bread and Durum Wheat Cultivars and Lines

The high molecular weight glutenin subunit (HMW-GS) composition of 42 Ethiopian-grown bread wheat and 31 durum wheat cultivars and lines were examined using SDS-PAGE. Low variability in HMW-GS composition was present in both classes of wheat. A total of 10 variants with 14 different HMW patterns and seven variants with six different patterns were identified in bread and durum wheat, respectively, reflecting the limited ability of HMW-GS for cultivar identification. The most predominant alleles were 2*, 7 + 9 and 5 + 10 in bread wheat and nul and 7 + 8 in durum wheat. The Glu-1 quality scores for bread wheat ranged from 6 to 10, with an average value of 8.7. The variation in HMW-GS significantly correlated with and accounted for 44 % of the total variation in gluten quality, measured by the sodium dodecyl sulphate sedimentation test. In durum wheat, HMW-GS variation at Glu-B1 explained about 25 % of the variation in gluten quality. The high frequency of the 7 + 8 alleles among the landraces and the significant contribution of Glu-B1 alleles to the total variation in gluten quality indicate the potential benefit of Ethiopian tetraploid landraces in the development of lines suitable for both bread and pasta production.     

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.     

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.     

Genetic diversity of European spelt wheat (Triticum aestivum ssp. spelta L. em. Thell.) revealed by glutenin subunit variations at the Glu-1 and Glu-3 loci

Summary High and low molecular weight glutenin subunit (HMW-GS and LMW-GS) compositions of 270 European spelts, 15 Iranian spelts and 25 bread wheat cultivars were analyzed by one- and two-dimensional gel electrophoresis. The results revealed a total of 22 HMW-GS alleles (4 at Glu-A1, 11 at Glu-B1 and 7 at Glu-D1) and 32 allele combinations among the three Glu-1 loci. Two major genotypes of HMW-GS: 1, 13+16, 2+12 and 1, 6.1+22.1, 2+12 were found to occur in Central European spelt wheat cultivars and landraces at higher frequencies of 35 and 28%, respectively. The Glu-B1 locus displayed the greatest variation and genetic diversity index (H) was 0.69 whereas Glu-A1 and Glu-D1 showed H index values of 0.26 and 0.19, respectively. The dendrogram constructed by HMW and LMW glutenin subunit bands revealed that European spelts form a separated cluster from common wheat suggesting that spelt and common wheat form distinct groups. In addition, all 15 Iranian spelt land variety accessions differed from European spelts and possessed similar HMW-GS alleles to common wheat. Because of a wider polymorphism Central European spelt wheats are an important genetic reserviour for improving common wheat quality. Both authors contributed equally to this work     

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.     

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.     

Relationships between different prolamin proteins and some quality properties in durum wheat

The objective of this paper was to study the differences between some prolamin variants coded at the loci Glu-3/Gli-1, Glu-1 and Gli-A2 and their relative roles in durum-wheat quality. F₃ lines from four durum wheat crosses (‘Abadia’בMexicali’. ‘Oscar’בArdente’, ‘Oscar × Mexicali’ and ‘Alaga’בC. of Balazote’) were analysed for gliadin and glutenin composition by electrophoresis. Whole-grain-derived samples were analysed for SDS sedimentation (SDSS) value, mixing properties, and contents of protein and vitreousness. The glutenin patterns LMW-2. LMW-2^? and LMW-2 (CB) at Glu-B3/Gli-B1 were associated with better gluten quality than were LMW-1 and LMW-2*. The glutenin subunits LMW4 and LMW3 + 15 at Glu-A3/Gli-A1 and HMW-1 showed better mixing properties than LMW7 + 12, LMW5 and the null phenotype. respectively. The HMW glutenin subunits 20 + 8 at Glu-B1 showed a negative association with gluten quality, but the rest of the HMW glutenin subunits and α-gliadins did not show any influence on gluten quality. Correlations between the results of the SDSS test and the mixograph were highly significant, but no correlation was found between these results and protein and vitreousness contents. The results are discussed in relation to the development of durum wheat varieties with improved qualities.     

小麦地方品种高分子量谷蛋白亚基多样性分析

采用SDS-PAGE方法,对我国9个麦区的76份代表性地方品种的高分子量谷蛋白亚基(HMW-GS)组成比较分析,并探讨其与环境因素(平均海拔、年平均降雨量和年平均温度)的相关性。结果表明,25.0%的品种具有异质性,分别包含2~4种不同HMW-GS组合;在Glu-1位点共检测到14个等位变异,其中Glu-A1、Glu-B1和Glu-D1等位变异数分别为2、7和5;发现了3个新等位变异,包括Glu-B1位点2个和Glu-D1位点1个。所有等位变异构成16种不同的亚基组合类型,以(N, 7+8, 2+12)为主,频率为69.7%。在Glu-1位点上,不同麦区遗传多样性分布存在一定的不均衡性,年平均降雨量和年平均温度与麦区多样性指数呈负相关。推测环境压力可能是地方品种多样性地区分化的重要因素。     

The high-molecular-weight glutenin subunit composition of Soviet wheat varieties

Summary One hundred and twenty-eight wheat varieties bred in the Soviet Union were screened for the composition of high-molecular-weight (HMW) subunits of glutenin. In general, variability was low compared to that seen in varieties from other countries. However, varieties from different regions showed distinctive patterns, in some cases clearly due to the use of particular parents in certain breeding programmes, but in others possibly due to the adaptive value of particular alleles to the environmental conditions under which the varieties were bred. For example, among spring varieties, the Glu-D1 allele encoding subunits 2+12 was more common in varieties from areas with limited rainfall than was the allele encoding subunits 5+10.The pattern of HMW glutenin subunits amongst varieties with superior bread-making quality showed few differences from that amongst bread-making varieties of lower quality.Abbreviations BMQ bread-making quality - HMW high-molecular-weight - LMW low-molecular-weight - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis     

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.     

Changes in expression of HMW glutenins of wheat (Triticum aestivum L.) induced by nitrosoethylurea

The application of a chemical mutagen, N-nitroso-N-ethylurea, to the grains of wheat (Triticum aestivum L.) cv. ‘Viginta’, provided a mutant line,‘NT-10′, with an altered composition of high molecular weight (HMW) glutenin subunits. The qualitative mutation was detected in the Glu-B1 locus by electrophoretic analyses of glutenins. Instead of the HMW glutenin subunits 7 + 9 present in the original genotype, a separate HMW subunit 6 was expressed in the mutant line. The other glutenin and gliadin proteins of the mutant line remained unchanged. The mutant line is also characterized by several changes in morphological and physiological characters—stronger stem, wider leaf, bigger spike and higher grain hardness. This is the first communication of the possibility of changing the composition of high molecular weight subunits of wheat glutenin by means of mutagenesis.     

Sources of resistance to tomato spotted wilt virus (TSWV) in cultivated and wild species of Capsicum

Summary The high molecular weight (HMW) subunits of glutenin extracted from flour of 36 Yogoslav wheat cultivars were separated by SDS-PAGE to identify their alleles, and the frequency of each allele was calculated. Eleven alleles from the three Glu-loci were recognized, three at the Glu-A1 locus, six at the Glu-B1 locus and two at the Glu-D1 locus. The most frequent allele was a (55.5%) from Glu-D1, which controls synthesis of subunits 2+12. The Glu-1 quality score varied from 4 (KG-III/27, KG-75, Morava and KG-101/7) to 10 (Lepenica). The mean Glu-1 quality score of cultivars and lines from Kragujevac was 6.8, for cultivars from Zagreb 7.2, and for cultivars from Novi Sad was 7.9. Most of the genotypes with a quality score of 8 or above, had high sedimentation values (Zeleny test). There were no significant differences in allelic composition at the Glu-1 loci among wheat genotypes from Kragujevac, Novi Sad and Zagreb.     

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.     

小麦高分子量麦谷蛋白亚基遗传变异及其与品质和其它农艺性状关系的研究

本研究应用SDS-PAGE技术分析了国内外757份供试材料的高分子量（HMW）麦谷蛋白亚基组成。共发现65种HMW亚基组成，其中53种为常见型，12种为罕见型。国外品种的亚基组合数多于国内品种，国内育成品种又多于国内地方品种。作者还发现了部分罕见亚基，即由Glu-D1编码的亚基2.2+12，2+10，2，12以及前人未曾发现的3个亚基。研究     

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.     

高分子量麦谷蛋白亚基组成与小麦烘烤品质关系研究

用SDS-PAGE方法测定了全国9个小麦主产省、市163个小麦品种和11个引进品种的高分子量麦谷蛋白亚基（HMW-GS）组成及其含量、沉降值和面粉GMP含量。结果表明，不同HMW-GS及其组合形式对小麦品质的影响显著不同，某些HMW-GS对我国小麦烘烤品质的影响不同于其他国家，如4+12亚基影响较大，而7+8亚基影响偏小。但单个亚基品质评分     

Biochemical and molecular characterisation of Glu-1 loci in Argentinean wheat cultivars

The high molecular weight glutenin subunit (HMW-GS) composition of acollection of 107 Argentinean bread wheat cultivars was analysed bysodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE).Allelic variation at the Glu-1 loci was identified and its frequencycalculated. Eleven alleles were detected, three encoded at the Glu-A1locus, six at the Glu-B1 locus and two at the Glu-D1 locus. Alow frequency of the null allele at the Glu-A1 locus and a highfrequency of subunits 5+10 at the Glu-D1 locus were observed.Reversed phase-high performance liquid chromatography (RP-HPLC)analysis was used to further characterise HMW-GS. Two different types ofBx subunit 8 (named subunits 8 and 8) were detected, the latterhaving shorter elution time. Subunit 8 was not identifiable bySDS-PAGE. According to quantification by RP-HPLC analysis, two groupsof subunit 7 were observed. One group, with a relatively high proportionof subunit 7 (approximately 39% of the total amount of HMW-GS)appeared in cultivars with allele 7+8 at the Glu-B1 locus; asecond group of subunit 7 (around 24% of the total amount ofHMW-GS), was found in alleles 7+8, 7+8 and 7+9. Restrictionfragment length polymorphisms (RFLP) analyses of HMW-GS genes werealso carried out after digestion of genomic DNA with HindIII andTaqI restriction enzymes. The relationship between DNA fragment sizeand glutenin subunits, as estimated by electrophoretic mobility inSDS-PAGE, was also examined. The restriction enzyme TaqIdemonstrated to be a useful tool to detect homozygous plants in selectionprograms against the Glu-A1 null allele.     

The high and low molecular weight glutenin subunits and ω-gliadin composition of bread and durum wheats commonly grown in Portugal

A collection of 63 bread wheats (Triticum aestivum L.) and 21 durum wheats (Triticum durum Desf.) commonly grown in Portugal since 1982 were characterized for the composition of wheat storage proteins (WSP), high molecular weight glutenin subunits (HMW-GS), low molecular weight glutenin subunits (LMW-GS) and ω-gliadins. The composition of HMW-GS, LMW-GS and &-gliadins, encoded at loci Glu-1, Glu-3 and Gli-1, respectively, was revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis. WSP allelic compositions of bread and durum wheat patterns were given. In the bread wheats, a total of 24, 24 and 18 patterns were observed for HMW-GS, LMW-GS and ω-gliadins, respectively. Forty-two different alleles were identified for the nine loci studied, Glu-A1 (3), Glu-B1 (7), Glu-D1 (4), Glu-A3 (5), Glu-B1 (7), Glu-D3 (2), Gli-A1 (2), Gli-B1 (8) and Gli-D1 (4). In the case of durum wheats, 19 alleles were identified: one allele at Glu-A1, two at Glu-B3, Glu-B2 and Gli-A1, three at Glu-B1, four at Glu-A3 and five at Gli-B1. For HMW-GS, LMW-GS and ω-gliadins, three, six and six different patterns were revealed, respectively. This study represents the first attempt to discriminate the bread and durum wheat varieties commonly grown in Portugal by the allelic variation of storage proteins. The database is useful for varietal identification and for plant breeders who seek to devise effective programmes aimed at improving wheat quality.