Relationships between dough strength,polymeric protein quantity and composition for diverse durum wheat genotypes

Five different Glu-B1 HMW-GS patterns were identified among a collection of diverse durum wheat genotypes grown in 2001 in two locations in western Canada. The durum wheat lines exhibited a wide range of dough and gluten strength characteristics as measured by alveograph and 2 g mixograph parameters, gluten index (GI), and protein composition as measured by unextractable polymeric protein (UPP) content and the ratio of high-molecular weight (HMW) glutenin subunits (GS) to low-molecular weight (LMW) GS. HMW-GS subunits patterns represented within the genotypes were 6+8, 7+8, 7+16, 14+15 and 20. Two of the genotypes expressed Glu-A1 HMW-GS 2* in combination with other HMW-GS. Approximately 95% of the durum genotypes were γ-gliadin 45 types. Analysis of variance indicated that genotype was a greater source of variation in all measurements than was growing location, with the exception of protein content which showed less variation contributed by genotype and more contributed by location than for other quality parameters. UPP was strongly associated with all strength measurements. All of the γ-gliadin 42 types were low in UPP and weak. Among the γ-gliadin 45 types, those possessing HMW-GS 20 were typically in the lower half of the UPP and strength range. There was no clear evidence of an association between any of the other HMW-GS patterns and gluten strength. The majority exhibited HMW to LMW-GS ratios that were within the relatively narrow range of 0.15–0.25, yet there were wide variations in dough strength among genotypes within that range. Increasing proportions of HMW-GS resulting in ratios of greater than 0.30 were generally associated with weak dough and gluten and low UPP content.     

The low-molecular-weight glutenin subunits of wheat gluten

Low-molecular-weight glutenin subunits (LMW-GS) are polymeric protein components of wheat endosperm and like all seed storage proteins, are digested to provide nutrients for the embryo during seed germination and seedling growth. Due to their structural characteristics, they exhibit features important for the technological properties of wheat flour. Their ability to form inter-molecular disulphide bonds with each other and/or with high-molecular-weight glutenin subunits (HMW-GS), is important for the formation of the glutenin polymers, which are among the biggest macromolecules present in nature, and determine the processing properties of wheat dough. Explanation of the structural basis for these correlations continues to intrigue researchers and, while earlier emphasis had been on HMW-GS, considerable attention is now being focused on the LMW-GS.LMW-GS are a highly polymorphic protein complex, including proteins with gliadin-type sequences. Difficulty in separating single components, arising from the complexity of the group, has limited the characterisation of the individual proteins and the establishment of clear-cut relationships with quality parameters.Here we review results concerning different aspects of LMW-GS, including their structural characteristics, genetic control, and relationships with quality parameters. In addition, we emphasise the distinction between the components with sequences unique to the LMW-GS fraction and those behaving like glutenin subunits (incorporated into polymers), but with sequences corresponding to gliadins.     

Contribution of common wheat protein fractions to dough properties and quality of northern-style Chinese steamed bread

Thirty-three cultivars and advanced lines originated from China, Mexico, and Australia were sown in four environments in Chinese spring wheat regions to investigate the association between gluten protein fractions determined by reversed-phase high-performance liquid chromatography (RP-HPLC), and dough properties and northern-style Chinese steamed bread (CSB) quality. The genotypes were divided into two groups of 10 and 23 entries with and without the 1B/1R translocation, respectively. 1B/1R translocation lines had significantly high amounts of ω  -gliadins, and low levels of glutenin and low molecular weight glutenin subunits (LMW-GS), but no significant difference in dough properties and CSB quality from non-translocation lines. The association between protein fractions and dough properties, and CSB quality largely depended upon the presence of 1B/1R translocation. Gliadin contributed more in quantity to flour protein content (FPC) than glutenin, while glutenin and its fractions contributed more to dough strength and CSB quality. Among non-translocation lines, moderate to high correlation coefficients between quantified glutenin and its fractions, and farinograph development time (DT, r=0.85$r=0.85$–0.92) and stability (ST, r=0.81$r=0.81$–0.93), extensograph maximum resistance (R_max, r=0.90$r=0.90$–0.93), CSB stress relaxation (SR, r=0.55$r=0.55$–0.61) and CSB score (r=0.56$r=0.56$–0.62), were observed. Gliadin:glutenin ratios showed significant and negative associations with dough properties and CSB quality. Correlation coefficients between gliadin:glutenin, gliadin:HMW-GS, gliadin:LMW-GS ratios, and CSB score were −0.79, −0.73, and −0.79 among non-translocation lines, respectively. HMW-GS and LMW-GS, x-type HMW-GS and y-type HMW-GS contributed similarly to dough properties and CSB quality for non-translocation lines. Weak correlations between protein fractions and dough properties, and CSB quality were observed among translocation lines. This information should be useful for improvement of dough properties and CSB quality.     

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.     

Ultra-fast separation of wheat glutenin subunits by reversed-phase HPLC using a superficially porous silica-based column

A relatively new, unique column packing material for reversed-phase high-performance liquid chromatography (RP-HPLC) was evaluated for rapid separation of wheat glutenin protein subunits. The product named “Poroshell” by the manufacturer consists of a solid core and a porous coat instead of solid silica spheres used in conventional RP-HPLC column packing. This architecture favours rapid mass transfer, facilitating faster reversed-phase separations of biomolecules compared to conventional silica columns. The main objective of this study was to evaluate the quality of separations of glutenin subunits (GS), as well as to optimize conditions to produce the fastest possible run times without sacrificing resolution using a Poroshell 300SB-C₈ 2.1×75 mm column. The stability of GS separations over time was also assessed. Two different bread wheat genotypes were used for optimization of separation conditions and six more common and durum wheat genotypes possessing different subunit combinations were used for further evaluation. Glutenin protein was extracted with 0.08 M Tris–HCl buffer (pH 7.5) containing 50% 1-propanol under reducing conditions after pre-extraction of soluble proteins with 50% 1-propanol. Optimization of GS resolution and sample throughput by RP-HPLC was assessed in response to variation in eluent flow rate, acetonitrile (ACN) gradient, and column temperature. The best resolution of both HMW- and LMW-GS was obtained in 13 min using a 23–44% ACN gradient with a flow rate of 0.7 mL/min at 65 °C. Subunit elution times and integrated areas were highly repeatable even after several hundred injections. Highly satisfactory separation of HMW-GS and quantification of ratio of HMW- to LMW-GS were achieved in less than 4 min per sample using a modified HPLC gradient. Ratio of HMW- to LMW-GS was unaffected by the speed of the separations. As well, the elution order of HMW- and LMW-GS was unaffected by the rapid analysis, compared to conventional RP-HPLC separations, so no new learning was required for interpreting chromatograms and classification of subunits. The rapid RP-HPLC method using the Poroshell column appears to be very well suited for routine quantification of HMW-GS and LMW-GS especially for purposes of wheat quality screening and wheat cultivar development activities where large numbers of samples are typically encountered.     

小麦-近缘物种染色体系的高分子量麦谷蛋白亚基组成及白粉病抗性

为了挖掘小麦近缘物种的高分子量麦谷蛋白新亚基和抗白粉病基因新类型,以小麦品种中国春和Alcedo(来自德国)为对照,对133份小麦-近缘物种染色体系进行了高分子量麦谷蛋白亚基(HMW-GS)分析和白粉病抗性调查。HMW-GS分析发现,25份材料与对照小麦的HMW-GS类型不同,其中,含外源染色体HMW-GS的有16份;亲本部分HMW-GS发生沉默的有2份;含外源染色体HMW-GS且亲本的部分HMW-GS发生沉默的有7份。在含外源HMW-GS的材料中,73.9%的HMW-GS来自于小麦近缘物种第1同源染色体,17.4%的HMW-GS来自第2、3和5同源染色体。白粉病抗性调查显示,尾状山羊草E#1、两芒山羊草2Mbi#1、沙融山羊草4Ssh#8、高大山羊草6Sl#3和簇毛麦5V#3S染色体上可能含有抗小麦白粉病新基因,值得进一步向小麦转育。本研究发现的新HMW-GS和潜在抗小麦白粉病新基因为利用这些资源进行小麦抗病育种与品质改良打下了坚实的基础。     

麦谷蛋白亚基对小麦品质特性的影响及其遗传转化

麦谷蛋白是小麦籽粒贮藏蛋白的重要组成部分,其亚基类型及组成与小麦品质密切相关,为了更进一步了解其与小麦蛋白质品质特性的关系,综合论述了小麦谷蛋白亚基的分类、结构及其不同亚基与小麦品质的关系,并对利用基因工程遗传转化方法改变小麦谷蛋白亚基组成从而提高小麦加工品质的现状及应用前景进行了讨论。     

Evidence for the Non-Glycoprotein Nature of High Molecular Weight Glutenin Subunits of Wheat

An isolation and purification procedure for wheat high molecular weight glutenin subunits (HMW-GS) involving no steps expected to cause deglycosylation of glycoproteins was developed to allow removal of the maximum amount of carbohydrates not covalently linked to HMW-GS. Flour was defatted and then extracted with 50%n-propanol (50%n-PrOH) to remove arabinogalactans and glucose-containing material. HMW-GS were extracted with 50%n-PrOH containing 5% β-mercaptoethanol, precipitated in 60%n-PrOH, alkylated and recovered by precipitation. The partially purified HMW-GS were separated by cation exchange chromatography and resulting fractions purified by RP–HPLC. The purified HMW-GS contained only 0·1% of glucose (corresponding to 51–59 monosaccharide residues per 100 HMW-GS molecules) and no other amino or neutral sugars. The HMW-GS gave a positive reaction in a periodate–digoxigenin glycan detection assay when labelled in solution (with or without periodate oxidation) but not when labelled directly on-the-blot. HMW-GS expressed inEscherichia coli, a micro-organism without glycosylation capabilities, reacted in an identical way. Possible reasons are given for the difference in results obtained after labelling in solution or on-the-blot. No positive reaction between the purified HMW-GS and mannose-specificGalanthus nivalisagglutinin was observed. The presence of N-acetylglucosamine in HMW-GS has been previously reported²⁰. Since neither mannose nor N-acetylgalactosamine were found in the HMW-GS, and these proteins lack the sequon necessary for N-glycosylation, only O-linked GlcNAc moieties are possible. This modification could not be detected using a galactosyltransferase labelling assay. Taken together these results suggest that HMW-GS are not glycosylated.     

Incorporation of high-molecular-weight glutenin subunits into doughs using 2 gram mixograph and extensigraphs

To study the contributions of high-molecular-weight glutenin subunits (HMW-GS) to the gluten macropolymer and dough properties, wheat HMW-GS (x- and y-types) are synthesized in a bacterial expression system. These subunits are then purified and used to supplement dough mixing and extensigraph experiments through dough partial reduction and reoxidation to allow these exogenously added HMW-GS to incorporate into gluten polymers. Detailed results are given for seven mixing and two extension parameters. HMW-GS synthesized in bacteria behaved similarly under these conditions to the same HMW-GS extracted from wheat flour. These experiments initially focused on the HMW-GS of the D-genome of hexaploid wheat encoded at the Glu-D1 locus; e.g. the Dx2, Dx5, Dy10, and Dy12 subunits. Experiments used five different flours and results are shown to be consistent when normalized to results from Dx5. The incorporation of Dx-type subunits into the gluten disulfide bonded network has greater effects on dough parameters than incorporation of Dy-type subunits. When Glu-D1 x- and y-type subunits are incorporated together, there are synergistic effects greater than those with either subunit type alone. This synergistic effect was greatest with approximately equal amounts of Dx- and Dy-type subunits - implying a 1:1 stoichiometric relationship.     

Correspondence between two minor Glu-A3 genes of durum wheat and their encoded polypeptides by using a proteomic approach

The low molecular weight glutenin subunits (LMW-GS) are wheat storage proteins participating to the formation of glutenin polymers that, along with the other gluten proteins, allow the accumulation of a large quantity of protein in the endosperm tissue. The size and composition of the glutenin polymers are directly related to gluten visco-elastic properties. In particular, LMW-GS composition is the factor most influencing durum wheat quality.     

Effect of nitrogen application rate on content of glutenin macropolymer and high molecular weight glutenin subunits in grains of two winter wheat cultivars

Two winter wheat (Triticum aestivum L.) cultivars differing in grain protein content were selected to study the effect of N application rate on changes in contents of glutenin macropolymer (GMP) and high molecular weight glutenin subunits (HMW-GS) during grain filling. Contents of GMP and HMW-GS were much higher in the high GPC cultivar, Xuzhou 26, than those in low GPC cultivar, Ningmai 9. N increased contents of GMP and HMW-GS in Xuzhou 26 with N rate between 0 and 300 kg ha⁻¹, while at the very high N rate of 300 kg ha⁻¹ the contents of GMP and HMW-GS in Ningmai 9 decreased. The high contents of GMP and HMW-GS at maturity were closely related to the rapid increase in contents of GMP and HMW-GS during the initial period of their synthesis. HMW-GS and GMP content were closely correlated. The total HMW-GS content was important in determining GMP content than the content of any HMW-GS pair or any individual HMW-GS present in the selected cultivars. The pattern of response of GMP content to N application rate was closely related to the regulatory effect of N on HMW-GS synthesis.     

The gluten protein and interactions between components determine mixograph properties in an F6 recombinant inbred linepopulation in bread wheat

One hundred and sixty-eight F₆ recombinant inbred lines (RILs) derived from Chinese wheat cultivars, PH82-2 and Neixiang188, were used to determine the cumulative effects of HMW-GS and LMW-GS composition and quantity of gluten protein fractions on dough mixograph properties. A wide range of variation for all parameters in the RILs was detected. Major gene loci of HMW-GS were associated with variation in mixograph characters, but accounted for no more than 25.3% of the phenotypic variations. Glu-D1, together with Glu-B3, played the most important role in determining the properties. Additive effects of HMW-GS and LMW-GS showed major contributions to most of the variation of mixograph parameters, and epistatic effects were also important and could be counter to additive effects of individual loci. The quantity of gluten protein fractions, especially the quantity of glutenin, LMW-GS, and Glu-B3, showed highly significant correlations with most of the quality parameters, but the correlation coefficients were influenced by grain hardness, protein content, or both. Protein quality could be greatly improved through increasing the quantity of glutenin, while holding desirable composition of HMW-GS and LMW-GS alleles, with an appropriate ratio of quantity of glutenin to gliadin.     

High throughput microchip-based separation and quantitation of high-molecular-weight glutenin subunits

Knowledge of glutenin subunit composition is important for the prediction of the genetic potential of breeding lines as these proteins are known to be responsible for the main differences in bread-making quality. In this study, a commercial high throughput microchip capillary electrophoresis-sodium dodecyl sulfate (microchip CE) platform, LabChip 90, was evaluated for qualitative and quantitative analyses of HMW-GS. 130 French common wheat varieties of known composition were analyzed for rapid identification and the allocation of individual HMW-GS. In addition, the HMW-GS were individually quantified and the ratio of HMW-GS to LMW-GS was determined for genotype comparison. The microchip CE analysis provides comparable resolution and sensitivity to conventional RP-HPLC for identification of the HMW-GS but at a time scale of approximately 100 times faster (45 s per sample analysis versus 80 min for RP-HPLC). The results show that the high throughput microchip CE method can be used for routine identification and quantitation of glutenin subunits, in particular for screening wheat quality and wheat cultivar development activities where large numbers of samples are to be evaluated.     

Biochemical Characterisation of a Novel Polymeric Protein Subunit from Bread Wheat (Triticum aestivum L.)

A new wheat endosperm protein subunit that was found in accessions belonging to different collections was identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Insoluble in 0·5 M NaCl, 70% ethanol, dimethyl sulphoxide (DMSO) and 50% propan-1-ol, it appeared in the pellet corresponding to the polymeric proteins along with high (HMW) and low molecular weight (LMW) glutenin subunits (GS). In the reduced form, it had an electrophoretic mobility between those two types of glutenin subunits. The apparent M_r of this novel protein was estimated by SDS-PAGE to be 71 000. N-terminal sequence and amino acid analyses indicated a composition similar to the ω-gliadins encoded by genes located on chromosome 1B. This protein can be ascribed to the D-subunits of LMW-GS with at least one cysteine residue that allows it to form part of the polymeric structure of glutenin, as shown by reaction with a fluorogenic reagent specific for sulphydryl groups. Fractions collected after size exclusion high-performance liquid chromatography (SE-HPLC) fractionation and further characterised by SDS-PAGE, confirm that the protein participates in the glutenin polymeric structure. An increase in its concentration was observed in fractions collected within the polymeric peak as elution time increased, implying that a larger amount of this protein is present in small size polymers. The role of this protein in the complex relationship between endosperm proteins and quality parameters is discussed in relation to its likely role as a chain terminator.     

Stacking HMW-GS transgenes in bread wheat: Combining subunit 1Dy10 gives improved mixing properties and dough functionality

We have determined the technological properties of four lines containing combinations of three HMW-GS transgenes, encoding HMW-GS 1Ax1, 1Dx5 and 1Dy10. These lines were produced by conventional crossing of three single transgenic lines of the bread wheat cultivar Anza that contains the endogenous HMW-GS pairs 1Dx2 + 1Dy12 and 1Bx7* + 1By8 and is null for the Glu-A1 locus. Consequently, the total number of HMW-GS ranged from 4 in the control line Anza to 7 in line T618 which contains all three HMW-GS transgenes. The lines were studied over two years using a range of widely used grain and dough testing methods. All lines with transgenic subunits showed higher levels of glutenin proteins than the Anza control, and these differences were highly significant for lines T616, T617 and T618, containing, respectively, the transgenes encoding HMW-GS 1Ax1 and 1Dy10, 1Dx5 and 1Dy10 and 1Ax1, 1Dx5 and 1Dy10. These increases in glutenin levels are compensated by lower levels of gliadins present in transgenic lines. These changes affected the ratio of polymeric to monomeric gluten proteins (poly:mono), the ratio of HMW-GS to LMW-GS (HMW:LMW) and the contents of individual 1Ax, 1Bx, 1By, 1Dx and 1Dy subunits. Transgenic lines expressing subunit 1Dy10 together with x-type subunits (T616, T617 and T618) were superior to line T606, which had only increases in x-type subunits. In particular, the combination of transgenic subunits 1Dx5 and 1Dy10 (line T617) gave better dough rheological properties than the other combinations of transgenic subunits. For example, dough development time and stability were increased by 3.5-fold and 8.5-fold, respectively, while the mixing tolerance index (MTI) was decreased by 3.3-fold in line T617 with respect to the control line. Alveograph analyses showed that all four transgenic combinations had increased P values compared to the Anza control but subunit 1Dx5 greatly reduced the extensibility (L). These results show that stacking HMW-GS transgenes by conventional crossing is a valid strategy for the improvement of wheat quality, with different effects being related to the different HMW-GS combinations.     

Factors Governing Levels and Composition of the Sodium Dodecyl Sulphate-Unextractable Glutenin Polymers During Straight Dough Breadmaking

The effect of several additives (1·215 μmol KIO₃, 0·892 μmol cysteine, endo-xylanase and 0·5% (w/w) rye-water-extractable arabinoxylans) on changes in the level and glutenin subunit composition of the sodium dodecyl sulphate (SDS)-unextractable protein during breadmaking was investigated. Protein extractability drastically increased during dough mixing and was enhanced both by cysteine and KIO₃. The mixing-induced increase in protein extractability was partly reversed during fermentation. Fermenting doughs containing endo-xylanase had a higher level of SDS-unextractable protein than control doughs, while with KIO₃the amount of SDS-unextractable protein remained very low. During baking most protein became SDS-unextractable. Bread baked from doughs with added KIO₃contained a significantly higher level of SDS-extractable protein. Changes in subunit composition of the SDS-unextractable glutenin polymers, determined with RP-HPLC, coincided with changes in protein extractability during dough processing. Mixing decreased the ratio of high to lowM_rglutenin subunits. Simultaneously, the relative proportions of the different highM_rglutenin subunits in the unextractable glutenin polymers changed. During fermentation changes in subunit composition of the SDS-unextractable glutenin were opposite to those during mixing.     

粗山羊草高分子量谷蛋白亚基组成分析

为了发现能够用于小麦品质改良的优异高分子量谷蛋白亚基(HMW-GS),应用SDS-PAGE技术分析了47份粗山羊草Glu-Dt1位点的HMW-GS组成,分别检测到5种x-型亚基(1.1t、1t、1.5t、2t、3t)和4种y-型亚基(10.1t、11t、12t、12.4t).其中,1Dx1.1t是1种新的x-型亚基,它的迁移率比普通小麦的1Ax1亚基稍慢,这是目前在粗山羊草中发现的分子量最大的HMW-GS.供试粗山羊草中有8种HMW-GS组合类型:1.1t 11t、1t 11t、1.5t 12t、2t 10.1t、2t 11t、2t 12t、2t 12.4t和3t 11t.其中,1.1t 11t和2t 12.4t未见报道.     

Molecular characterization of storage proteins for selected durum wheat varieties grown in different environments

The variations of the amounts of individual high molecular weight glutenin subunits (HMW-GS), of the ratios HMW-GSy to HMW-GSx and HMW-GS to low molecular weight glutenin subunits (LMW-GS) and of protein content were evaluated for eight durum wheat cultivars in two regions using four fertilizer combinations during two successive years. All measured parameters showed significant variation with genotypes (G), environments (E) and fertilizers (F). The interaction E × G × F was highly significant for glutenin amount variation. Amongst cultivars possessing HMW-GS 20, landraces seem to better value the N-fertilizer use for the accumulation of HMW-GSy than high yielding cultivars. Both HMW-GSy to HMW-GSx and HMW-GS to LMW-GS ratios were found to be positively correlated (p < 0.05) with total protein content.     

Comparative Studies of High MrSubunits of Rye and Wheat. II. Partial Amino Acid Sequences

A panel of anti-peptide antibodies specific for each of the different N-terminal sequence types of B- and C-low molecular mass glutenin subunits (L M_rGS) were utilised in immunoblotting studies to identify the chromosomal location of genes encoding different sequences and to characterise the allelic variation of the encoding loci. The MET-type sequences were predominantly found among the B- subunits, while the α- and γ- sequences predominated in the C- subunits. The quantitatively major SHIPGLERPS sequence was found in both the B- and C- mobility regions. Using either biotypes in the cultivar, Aroona or genetic lines containing double rye chromosome 1 substitutions and thus expressing only single LM_r GS alleles, the sequences were determined for most of the major polypeptides expressed by each LM_r GS allele. The L M_rGS from different genomes encoded different numbers of each sequence type. Furthermore, different polypeptides within a particular «block» of subunits encoded by a given allele often had differing N-terminal sequences. However, subunits of similar electrophoretic mobilities encoded by different alleles at each locus usually had identical N-terminal sequences, suggesting that they may instead differ in the number of repeats. In Chinese Spring, genes encoding the SHIPGLERPS and METSHIPGL sequence types were predominantly present on chromosomes 1B and 1D, while the related METSRVPGL sequence was only encoded on 1D. In contrast, the METSCIPGL, α- and γ-sequences were encoded on each of chromosomes 1A, 1B and 1D. Several different electrophoretic and immunoblotting approaches using null lines suggested that some of the α-type L M_rGS may also be encoded by group 6 chromosomes, particularly 6D. The anti- SHIPGLERPS antibody also recognised chromosome 1B encoded β-, γ- and ω-gliadins, while the anti-METSRVPGL antibody recognised 1D encoded α- and β-gliadins. The absence of sequences within the major gliadin families that are highly homologous to the latter two N-terminal L M_rGS sequences may suggest that some monomeric L M_rGS could exist within the electrophoretically-resolved gliadins. These antibodies will provide valuable reagents for the study of the roles of particular L M_rGS families in the structure and function of the glutenin macropolymer, the role of different LM_r GS types in determining the influence of allelic variation of L M_rGS composition on dough properties, and potentially in the development of diagnostics for these flour components.     

甘肃小麦品种(系)HMW-GS遗传变异分析

为了了解甘肃省小麦品种HMW-GS的遗传变异和组成，为甘肃优质专用小麦品种筛选和品种改良提供依据,采用SDS-PAGE法，分析了254份甘肃省小麦材料(育成品种(系)和农家品种)Glu-1位点的HMW-GS变异，共检测到22种HMW-GS变异，Glu-A1位点3种，Glu-B1位点11种，Glu-D1位点8种。其中110个育成品种(系)的15种HMW-GS有27种亚基组合类型。Glu-A1位点有2种亚基，47．3％的品种该位点具有优质亚基；Glu-B1位点有7种亚基，76．4％的品种具优质亚基；Glu-D1位点有6种亚基，32．7％的品种具优质亚基。14．5％的品种(n：15)Glu-1位点具优质亚基。144份农家品种的18种HMW-GS共有29种亚基组合形式，Glu-A1位点有3种亚基,Glu-B1位点有9种亚基，Glu-D1位点有6种亚基，无优质亚基组合。