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1.
The x- and y-type high molecular weight (HMW) glutenin subunits are conserved seed storage proteins in wheat and related species. Here we describe investigations on the HMW glutenin subunits from several Pseudoroegneria accessions. The electrophoretic mobilities of the HMW glutenin subunits from Pd. stipifolia, Pd. tauri and Pd. strigosa were much faster than those of orthologous wheat subunits, indicating that their protein size may be smaller than that of wheat subunits. The coding sequence of the Glu-1St1 subunit (encoded by the Pseudoroegneria stipifolia accession PI325181) was isolated, and found to represent the native open reading frame (ORF) by in vitro expression. The deduced amino acid sequence of Glu-1St1 matched with that determined from the native subunit by mass spectrometric analysis. The domain organization in Glu-1St1 showed high similarity with that of typical HMW glutenin subunits. However, Glu-1St1 exhibited several distinct characteristics. First, the length of its repetitive domain was substantially smaller than that of conventional subunits, which explains its much faster electrophoretic mobility in SDS-PAGE. Second, although the N-terminal domain of Glu-1St1 resembled that of y-type subunit, its C-terminal domain was more similar to that of x-type subunit. Third, the N- and C-terminal domains of Glu-1St1 shared conserved features with those of barley D-hordein, but the repeat motifs and the organization of its repetitive domain were more similar to those of HMW glutenin subunits than to D-hordein. We conclude that Glu-1St1 is a novel variant of HMW glutenin subunits. The analysis of Glu-1St1 may provide new insight into the evolution of HMW glutenin subunits in Triticeae species.  相似文献   

2.
Seven transgenic lines of a commercial wheat (Triticum aestivum L.) cultivar expressing transgenic subunits 1Ax1, 1Dx5 and 1Dy10, alone or in combination have been developed. Pasting properties were determined in these transgenic lines using a Rapid Visco Analyser (RVA) in order to determine the possible impact of HMW-GS transgene expression on the starch properties. Expression of the HMW-GS transgenes increased the proportions of the corresponding 1Ax, 1Dx and 1Dy subunits affecting significantly the ratios of HMW-GS:LMW-GS and x-type:y-type HMW-GS. Starch granule size distribution varied significantly among all transgenic lines, with the Anza control and transgenic line T616 (expressing subunits 1Ax1 and 1Dy10) showing the highest and the lowest percentage of B granules, respectively. All transgenic lines increased the water-binding capacities (WBC) at 25 °C and 90 °C. Line T606 (expressing subunits 1Ax1 and 1Dx5) and line T590 (expressing subunit 1Dy10) showed the lowest and the highest values for peak viscosity, respectively. Notably, lines expressing only transgenic x-type subunits (T580, T581 and T606), with high ratios of x-type:y-type HMW-GS, had low peak viscosities, final viscosities and breakdown viscosities. Line T590 had the highest breakdown viscosity while lines T606 and T581 had the lowest.  相似文献   

3.
The structural features of highMrglutenin subunits of wheat were compared with those of analogous proteins from rye. Subunits of two rye cultivars (Danko and Halo) and of the wheat cultivar Rektor were isolated from defatted flours by extraction with 50% (v/v) aqueous propan-1-ol under reducing conditions at 60°C followed by precipitation using a 60% concentration of propan-1-ol. The yields of dialysed and freeze-dried subunits were 0·33% and 0·32% (w/w of flour), respectively (rye cultivars), and 0·91% (Rektor). SDS–PAGE revealed that the rye cultivars contained at least five subunits with mobilities corresponding to the x-type subunits of wheat. Separation by RP–HPLC indicated that the rye cultivars did not differ in the qualitative composition of subunits, but in their quantitative proportions. The surface hydrophobicities of the rye subunits were significantly lower than those of wheat subunits. The amino acid compositions of single rye subunits were characterised by high contents of Glx, Gly and Pro, and they were closely related to those of wheat subunits, except that the Glx content was generally lower and the Cys content higher. Notable differences between rye and wheat subunits were found in their contributions to gluten strength. Whereas wheat subunits, reoxidised with potassium bromate and mixed with a standard wheat flour, caused a significant increase in gluten strength, reoxidised rye subunits had the opposite effect.  相似文献   

4.
Glutelin, a major protein in rice grains, is encoded by a multigene family. However, its protein composition is not well characterised. Here, we identified and characterised two novel glutelin subunits, GluBX and GluC. The individual glutelin subunits of japonica cv. Nipponbare and indica cv. 93-11 rice were analysed using 2-dimensional gel electrophoresis, LC–MS/MS, and Western blotting. Comparison of the glutelin profiles between three japonica and three indica cultivars indicated two distinct subunits (GluA-1 and GluA-3 isomers) and a distinction in the subunit composition (notably GluA-3 and Lys-rich GluB-1 components) of these two subspecies. Sequence alignment revealed different nutritional (Lys residues) and functional (Cys residues) characteristics between the type-A and type-B glutelin subfamilies. We also analysed amino acid and total protein contents of the grains in thirty-five cultivars, and we demonstrated that the Lys-rich glutelin composition of indica cultivars is superior to that of japonica cultivars. The Lys-rich and Cys-poor GluBX subunit is a native protein and is a high nutritional protein in grains. Our combined approaches for the identification of glutelin subunits have revealed the nutritional characteristics of individual subunits in rice, and this knowledge will provide new insights for improving grain quality during rice breeding.  相似文献   

5.
甘肃小麦品种(系)HMW-GS遗传变异分析   总被引：4，自引：1，他引：4  
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。  相似文献   

6.
An aspartic proteinase (EC 3.4.23) was purified 31 300-fold with 6% recovery from wheat gluten by ammonium sulphate precipitation, affinity-chromatography on pepstatin A-agarose and gel permeation chromatography. The enzyme has no amino- or carboxypeptidase activity and is a heterodimer with subunits of apparent molecular mass c. 11 and 29 kDa. It has an iso-electric point of c. 4·55. The enzyme is maximally active against haemoglobin at pH 2·5 and between 45–50°C and is completely inhibited by pepstatin A. The sequence of the first 20 N-terminal amino acids of the 11 and 29 kDa subunits have 90% and 95% identity, respectively, with the N-terminal amino acid sequences of the 11 and 29 kDa subunits of barley aspartic proteinase.  相似文献   

7.
部分抗条锈冬小麦高分子量谷蛋白亚基组成分析   总被引：1，自引：0，他引：1  
为了加强小麦抗条锈遗传资源在品质育种上的进一步利用,以甘肃省育成的对当前优势条锈菌小种高抗或免疫的冬小麦新品种(系)59份及引进品种35份为试验材料,应用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)方法分析了这些品种的高分子量谷蛋白亚基(HMW-Gs)组成。结果表明．参试的抗条锈冬小麦资源的亚基组成较丰富．共检测到14种亚基及19种亚基组合类型。供试材料所含的优质亚基中．1、7 8、5 10亚基出现频率占主导地位,其它优质亚基很少;品质评分在3～10之间,平均为6．5分,表明品质普遍较差。本实验还筛选出一批含2～3个优质亚基组合的材料。  相似文献   

8.
In this work we report the effects of the HMW-GS 1Ax1, 1Dx5 and 1Dy10 on the breadmaking quality of the bread wheat cultivar Anza that contains the HMW-GS pairs 1Dx2 + 1Dy12 and 1Bx7* + 1By8, and is null for the Glu-A1 locus. This allows the characterization of individual subunits 1Dx5 and 1Dy10 in the absence of subunit 1Dx5, and the interactions between these subunits and subunits 1Dx2 and 1Dy12 to be determined. Three transgenic lines termed T580, T581 and T590, containing, respectively, the HMW-GS 1Ax1, 1Dx5 and 1Dy10 were characterized over 3 years using a range of widely-used grain and dough testing methods. The transgenic subunits 1Ax1, 1Dx5 and 1Dy10 accounted for 25.2%, 20.3% and 17.9%, respectively, of the total HMW-GS in the three transgenic lines. Although lines T581 and T590 expressed similar levels of subunits 1Dx5 and 1Dy10 they had different effects on other aspects of protein composition, including changes in the ratios of glutenin/gliadin, of HMW/LMW-GS, the 1Dx2/1Dy12, the x-type/y-type HMW-GS and the proportions of high molecular mass glutenin polymers. In contrast, lines transformed to express subunits 1Ax1 and 1Dx5 showed similar changes in protein composition, with higher protein contents and decreased ratios of glutenin/gliadin and 1Dx2/1Dy12. In addition, both transgenic lines showed similar increases in the ratio of x-type/y-type subunits compared to the control line. The transgenic lines were analysed using Farinograph, Mixograph and Alveograph. This confirmed that the expression of all three subunits resulted in increased dough strength (and hence breadmaking quality) of the cultivar Anza. A beneficial effect of subunit 1Dx5 has not been reported previously, transgenic wheat lines expressing this subunit giving overstrong dough unsuitable for breadmaking. However, the expression of subunit 1Dy10 had a greater effect on breadmaking quality than subunits 1Ax1 and 1Dx5. The Farinograph parameters such as dough stability and peak time were increased by 9.2-fold and 2.4-fold, respectively, in line T590 (expressing 1Dy10) with respect to the control line. Similarly, the Mixograph mixing time was increased by four-fold and the resistance breakdown decreased by two-fold in line T590 compared with the control line. The Alveograph W value was also increased by 2.7-fold in line T590 compared to the control line. These transgenic lines are of value for studying the contribution of specific HMW-GS to wheat flour functional properties.  相似文献   

9.
为了了解贵州小麦品质育种状况,利用SDS-PAGE技术分析了50份省内外小麦品种(系)高分子量麦谷蛋白亚基(HMW-GS)的遗传组成情况．并进行亚基品质评分。结果表明,贵州省内品种Glu-1位点具有丰富的遗传变异．共检测到12种亚基和14种亚基组合类型;贵州省内材料HMW-GS品质评分较低．平均只有4．07分,而省外品种平均为5．33分．主要原因是省内外材料Glu-D1位点的优劣亚基分布频率差异较大,省内材料中优质亚基5 10的出现频率只有14．3％．而评分最低的2 12亚基的出现频率却高达85.7％,省外材料中5 10亚基和2 12亚基均以40％的频率出现;贵州小麦育种还需在品质方面加强优质亚基的利用。  相似文献   

10.
In an attempt to detect highMrglutenin subunits specifically by immunochemical means, antisera were produced against synthetic peptides corresponding to three N-terminal sequences and to two repetitive motifs of highMrglutenin subunits. The three N-terminal peptides, NT1, NT2 and NT3, differed by a single substitution at the sixth position and correspond, respectively, to the N-termini off Dx subunits, Ax and Bx subunits and By and Dy subunits. The anti-peptide sera did not cross react with gliadins or with lowMrglutenin subunits, and differed in their ability to recognise highMrglutenin subunits. The antisera to the repetitive motifs recognised all highMrglutenin subunits, whereas the antisera to the N-terminal peptides detected only some of the subunits. The antiserum directed against the N-terminal peptide from Dx subunits detected these subunits specifically, whereas the antiserum directed against the N-terminal peptide corresponding to y type subunits did not react with the homologous subunits although it did react with Dx or Bx subunits. Antisera were also produced against internal sequences present in the N-terminal domain specific for x and for y-type subunits, but these antisera did not react with the cognate proteins. The failure of some anti-peptide sera to recognise the homologous highMrglutenin subunits may be due to differences in conformation between peptides and the corresponding regions in proteins.  相似文献   

11.
Putative continuous epitopes, recognised by five panels of monoclonal antibodies (MAb) with differing specificities for gliadins and glutenin subunits, were identified using overlapping nonapeptides. These peptides corresponded to the entire sequence of an α/β-gliadin, a γ-gliadin, an ω-prolamin (homologous to ω-gliadin), a low molecular weight glutenin subunit (L MrGS) and several high molecular weight glutenin subunits (HMr GS). Antibodies that bound to γ- or ω-gliadins, L MrGS or HMr GS bound to the peptides at similar concentrations used normally in direct ELISA, but little binding to the peptides was seen for several antibodies that bound specifically to small groups of α/β-gliadins. Epitopes for these antibodies in α/β-gliadin may be discontinuous (i.e. derived from amino acid residues that are brought together by folding of the polypeptide chain or by juxtaposition of two polypeptide chains), since binding of these antibodies to gliadins was greatly decreased following the reduction of intra-molecular disulphide bonds. While some regions in particular subunits were immunodominant, such as the cysteine–cysteine containing peptide found in the central domain of many prolamins, a diversity of reaction patterns was found. Cross-reaction of antibody with peptides from other prolamin families was often due to binding to a peptide having significant sequence homology, but in some cases no homology was obvious. Some major trends were as follows. Antibodies which bound to most or all H MrGS recognised the central repeat region, while those that were selective for one or two subunits bound to epitopes in the unique N- and/or C-terminal domains. A high proportion of the epitopes recognised by MAb to α-, β-, ω-gliadins and L MrGS contained cysteine; these MAb may be useful in detecting covalent binding sites within or between subunits. Although a number of MAb bound a wide range of gliadins and GS, several of these recognised single (and differing) epitopes in the target proteins. However, comparatively few MAb recognised epitopes from either the N- or C-terminal regions of the target proteins. Several explanations are possible; either these regions are buried in the immunogen and not accessible for antibody production or alternatively the repeat sequences are immunodominant.  相似文献   

12.
高分子量麦谷蛋白亚基变异与加工品质关系的研究   总被引：20，自引：7，他引：13  
用扬麦１５８分别与强面筋品种安农９１９２和Ｋａｒｌ组配成２个杂交组合,分析了其Ｆ４代９３个株系的高分子量谷蛋白亚基组成及有关品质性状,研究了不同的高分子量麦谷蛋白亚基及亚基组合对品质性状的影响。结果表明,Ｇｌｕ－Ａｌ的等位变异（亚基１和Ｎ）Ｇｌｕ－ｄｌ的等位变异（亚基５＋１０和２＋１２）对ＳＤＳ沉淀值、和面时间、耐揉性和ＧＭＰ含量有显著影响,对蛋白质含量、和面图峰高的影响较小。亚基１和５＋１０与强  相似文献   

13.
Low molecular weight (LMW-GS) and high molecular weight glutenin subunits (HMW-GS) were added to a base flour using both «addition» and «incorporation» protocols. «Incorporation» of glutenin subunits into the glutenin network of the base flour was performed by partial (reversible) reduction and subsequent reoxidation of the glutenin network in the presence of the added glutenin subunits whereas, in the «addition» protocol, glutenin subunits were added without reduction/oxidation. The effects of both «addition» and «incorporation» of alkylated and unalkylated LMW-GS and HMW-GS on dough extension parameters maximum resistance (MR) and extensibility (EX) were compared and thoroughly discussed. HMW-GS and LMW-GS had totally different effects on dough extensibility. «Addition» of LMW-GS significantly decreased both MR and EX whereas HMW-GS caused a significant increase in MR. «Incorporation» of LMW-GS caused a decrease in MR whereas HMW-GS clearly increased MR. The similarity in effects obtained with «addition» and «incorporation» of glutenin subunits indicated that, even with «addition», glutenin subunits can be partially incorporated into the glutenin network in the presence of oxygen. Alkylated and unalkylated glutenin subunits had different effects. This was probably caused by the effect of free sulphydryl groups in unalkylated subunits (possibility of SS/SH exchanges and/or incorporation) and/or the effect induced by introduction of alkylated derived substituents. A protocol for «incorporation with excess KIO3» was developed to exclude the possible effect of a lowering of the available oxidant concentration by oxidation of free sulphydryl groups in glutenin subunits. However, the use of high levels of oxidant in the «incorporation with excess KIO3» protocol seems to overrule the effects of added glutenin subunits or may force glutenin subunits to incorporate differently from what can be observed under gentle oxidation conditions. Therefore, «incorporation with excess KIO3» is not suitable for studying the effects of incorporation of glutenin subunits on dough extensibility.  相似文献   

14.
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.  相似文献   

15.
A large collection of accessions of the wild wheat progenitor Triticum tauschii, the donor of the D genome of Triticum aestivum, was evaluated for the variability of high molecular weight (Mr) glutenin subunits by electrophoretic and chromatographic methods. A large range of allelic variation at theGlu-Dt1 locus was found in this collection and some novel subunits were observed in both x- and y-type glutenin subunits, including x- or y-type null forms. A few accessions showed three bands in the high Mrglutenin subunit region. However, only two subunits were observed when monomeric proteins were removed before SDS-PAGE analysis of polymeric proteins. The presence of monomeric proteins in this region is discussed. Characterisation of these subunits was also carried out by reversed phase-high performance liquid chromatography (RP-HPLC). Very different surface hydrophobicities were observed between x- and y-type subunits and in some cases it was possible to identify glutenin subunits with the same apparent molecular weight but different surface hydrophobicity. Differences in elution times that were detected when the same subunit was either reduced or reduced and alkylated were related to the number of cysteine residues present in each glutenin subunit. The newGlu-Dt1 glutenin subunits have the potential to enhance the genetic variability available for improving the quality of bread wheat (T. aestivum).  相似文献   

16.
为了给新疆优质小麦品种的选育和改良提供科学依据，应用SDS-PAGE方法对来源于南疆的169个小麦品种(系)的HMW-GS组成与分布进行了系统分析。结果表明，Glu-A1住点有两种等位变异类型Null和1；Glu-B1住点有7、7 8、7 9、6 8、17 18、14 15、21共7种等住变异类型，且主要以7 8和7 9为主；Glu-D1位点有2 12、4 12、5 i0、2 10、2．2 12共5种等位变异类型，且以2 12和5 10为主。本文还研究了这些HMW-GS(或组成)出现的频率和特点。  相似文献   

17.
为了解黄淮麦区小麦新品种(系)的品质状况,用SDS-PAGE方法对227份材料的HMW-GS组成进行了分析,共检测到10种等位基因变异和18种亚基组合,其中,各位点的主要亚基有:Glu-A1位点的1(61.67%),Glu-B1位点的7+9(62.11%)和7+8(21.59%),Glu-D1位点的2+12(53.30%)和5+10(40.97%);主要的亚基组合为"1,7+9,2+12"(21.59%)和"null,7+9,2+12"(19.38%)。研究表明,黄淮麦区小麦HMW-GS等位变异和亚基组合的多态性较为丰富,但分布严重不均,仍需引进含有2*、13+16和17+18等亚基的材料;优质亚基5+10和14+15的比例有所提高,但优质亚基组合的比例仍然很低,今后该地区小麦品质育种中应加强优质亚基组合的选择。  相似文献   

18.
圆锥小麦高分子量谷蛋白亚基组成分析   总被引：5，自引：3，他引：5       下载免费PDF全文
为了寻找新的基因资源，为小麦品质改良提供基础材料，应用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)方法，对中国西部和北部地区123份圆锥小麦材料高分子量谷蛋白亚基(HMW-GS)的组成进行了分析，共检测到15种HMW—GS组合类型。14个等位变异中有5种类型即Glu-Al-Ⅰ、Glu-B1-Ⅰ、Glu-B1-Ⅱ、Glu-B1-Ⅲ、Glu-B1-Ⅳ在普通小麦中不常见。类似于17 18亚基组合的Glu-B1-Ⅲ分布频率高达到63．40％，亚基2^*出现的频率远远高于普通小麦，另外发现一份含有编码与小麦抗病性关系密切的21亚基的材料可应用于小麦抗病育种中。分析结果表明，圆锥小麦的HMW—GS共有丰富的多态性和亚基组合类型，优质亚基分布频率高，是小麦育种的宝贵基因资源。  相似文献   

19.
水肥模式对小麦产量、品质和HMW GS表达量的影响   总被引：1，自引：0，他引：1  
为给小麦高产优质育种和栽培提供理论依据,以临Y7287为材料（亚基类型：1,7＋9,5＋10）,研究5种水肥模式对小麦产量、品质和HMW-GS表达量的影响。结果表明,水肥模式4[适期晚播,冬前限量灌水（450 m3.hm-2）、拔节期增量灌水（900 m3.hm-2）,施N 225 kg.hm-2,底追比7∶3]的小麦籽粒产量、湿面筋、沉降值、稳定时间和评价值最高,并且有利于1、5、10亚基的积累和形成,其中对1、5亚基的影响较大。不同水肥模式下,小麦HMW-GS形成时间和积累强度动态变化规律基本一致,均随着籽粒灌浆的进行,亚基相继形成,谱带逐渐稳定,积累量也逐渐增加,谱带颜色加深。花后20 d亚基完全形成,但不同水肥模式下HMW-GS形成时间有差异,水肥模式4亚基形成最快。因此,在小麦生产管理中,可选择水肥模式4实现小麦优质高产。  相似文献   

20.
None of the oxidation conditions in previous work on polymerisation of wheat glutenin subunits with inorganic oxidants allowed for complete polymerisation. We here investigated the polymerisation efficiencies of molecular oxygen (slow-acting oxidant), and potassium iodate (fast-acting oxidant). On a small scale, both polymerised the glutenin subunits very efficiently under the conditions used. Only low levels of residual monomer were left in polymerised glutenin subunit mixtures and the resulting polymers were almost exclusively of very high molecular weight. Oxygen was used in further preparative scale polymerisation. Up-scaling lowered the polymerisation efficiency and also resulted in the formation of lower molecular weight polymers. Similarly to observations in small scale polymerisation, low molecular weight glutenin subunits polymerised more efficiently than high molecular weight glutenin subunits. Preparative scale polymerisation of high and low molecular weight subunits and subsequent addition of the resulting mixture to a base flour decreased both maximum resistance and extensibility. Because the oxidised subunits contained a high level of insoluble polymer, the decrease in maximum resistance upon polymer addition was unexpected. A well-defined reason for the dough weakening effect of the polymer cannot be given.  相似文献   

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