Separate effects on gluten strength of Gli-1 and Glu-3 prolamin genes on chromosomes 1A and 1B in durum wheat

Two recombinants between Gli-A1 and Glu-A3 prolamin genes and seven between Gli-B1 and Glu-B3 obtained from two crosses of durum wheat were classified on the basis of the prolamin alleles at the Glu-A1, Gli-A1, Glu-A3, Gli-A2, Glu-B1, Gli-B1 and Glu-B3 loci. The separate effects on gluten strength of gliadin genes at Gli-1 and low M_r glutenin subunit genes at Glu-3 were estimated by comparing the SDS-sedimentation test values of the recombinants with those of the same progeny having the same prolamin composition, except for the recombined alleles. The results showed clearly that low M_r glutenin subunit genes at Glu-A3 and Glu-B3, rather than gliadin genes at Gli-A1 and Gli-B1, were responsible for the differences in gluten strength.     

High frequency of abnormal high molecular weight glutenin alleles in Chinese wheat landraces of the Yangtze-River region

A total of 485 common landraces of bread wheat were collected from the Yangtze-River region of China. Their high molecular weight glutenin subunit (HMW-GS) composition was analyzed by Matrix-assisted laser desorption/ionization time-of-flight Mass Spectrometry (MALDI-TOF-MS). Among all landraces tested, 453 were homogeneous for HMW-GS, 32 were heterogeneous, and 37 contained abnormal subunits. A total of 22 alleles were detected, including 3 at Glu-A1, 13 at Glu-B1 and 6 at Glu-D1, respectively. Higher variations occurred at the Glu-B1 locus compared with Glu-A1 and Glu-D1. Glu-A1c (74.0%), Glu-B1b (40.4%), Glu-D1a (84.9%) appeared to be the most frequent alleles at Glu-A1, Glu-B1 and Glu-D1, respectively. Two alleles ("null" and 1) at the Glu-A1 locus, three allele compositions (7 + 8, 7OE + 8, 7 + 9) at the Glu-B1 locus, and two (2 + 12 and 5 + 10) at the Glu-D1 locus appeared to be the common types in the 485 landraces. Sixteen new alleles represented by abnormal subunits were identified at the Glu-B1 and the Glu-D1 locus.     

New B low Mr glutenin subunit alleles at the Glu-A3, Glu-B2 and Glu-B3 loci and their relationship with gluten strength in durum wheat

The B low M_r subunits of glutenin of the F₂ generation from three durum wheat crosses were analysed. Three new alleles were found at three different loci: Glu-A3i coding for 5+20 subunits, Glu-B2c coding for subunit 12* and Glu-B3l coding for 1+3+13*+16 subunits. The genetic distances between Glu-A3-Gli-A1, Glu-B2-Gli-B1, Glu-B3-Glu-B2 and Glu-B3-Gli-B1 were calculated. The effects of the allelic variation at the Glu-A3, Glu-B2 and Glu-B3 on protein content and gluten strength, as measured by the SDS-sedimentation test, were determined using F₄ lines from the three crosses. All the new alleles affected significantly gluten strength. The presence of Glu-A3i had a negative influence on SDSS values compared with the allele a. For Glu-B2 and Glu-B3 the data obtained enable the effects of the alleles on SDSS volume to be ranked: a=b>c for Glu-B2 and a>b>l for Glu-B3. The results also shown that the allelic variants at Glu-B3 had a much greater effect on gluten strength than the variants at Glu-A3 or Glu-B2 loci. A high percentage of variation in sedimentation volume was explained by the prolamins (52 and 70%).     

Effects of allelic variation of HMW-GS and LMW-GS on mixograph properties and Chinese noodle and steamed bread qualities in a set of Aroona near-isogenic wheat lines

High-molecular-weight glutenin (HMW-GS) and low-molecular-weight glutenin (LMW-GS) subunits play an important role in determining wheat quality. To clarify the contribution of each subunit/allele to processing quality, 25 near-isogenic lines with different HMW-GS and LMW-GS compositions grown at two locations during the 2010 cropping season were used to investigate the effects of allelic variation on milling parameters, mixograph properties, raw white Chinese noodle (RWCN) and northern style Chinese steamed bread (NSCSB) qualities. The results showed that Glu-B1 and Glu-B3 made a large contribution to determining mixograph properties and processing quality, respectively. Subunit pairs 17 + 18 and 5 + 10, and alleles Glu-A3b, Glu-A3d, Glu-B3g and Glu-D3f made significant contributions to mixograph properties and no significant difference was detected on most parameters of RWCN and NSCSB for the allelic variation of HMW-GS and LMW-GS. The allelic interactions among glutenin loci had significant effects on wheat quality. The line with 1, 17 + 18, 2 + 12, Glu-A3c, Glu-B3b, Glu-D3c associated with superior mixograph properties, the line with 1, 7 + 9, 2 + 12, Glu-A3c, Glu-B3d, Glu-D3c had superior viscoelasticity of RWCN, and the line with 1, 7 + 9, 2 + 12, Glu-A3e, Glu-B3b, Glu-D3c had the highest total score of NSCSB. These results provide useful information for genetic improvement of the qualities of traditional Chinese wheat products.     

Influence of allelic prolamin variation and localities on durum wheat quality

Thirty-seven varieties of a Mediterranean durum wheat collection grown in Tunisia and Spain were analysed for their allelic composition in prolamins, as well as their protein concentration, sodium dodecyl sulphate sedimentation (SDSS) test and mixograph parameters. Genotype was a greater source of variation in all measurements than locality. Uncommon high and low molecular glutenin subunits (HMW-GS and LMW-GS) were found (V and 2•• subunits at Glu-A1, 13 + 16 at Glu-B1, 5* subunit and ax allele at Glu-A3). The rare combinations 2 + 4+14 + 18 and 8 + 9+13 + 16+18 subunits at the Glu-B3 locus were found. Glu-A3ax had a positive influence on SDSS and mixograph parameters. Of all the prolamins, those that have the B-LMW-GS composition aaa (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d gave the best semolina quality. By contrast, semolina quality is poor when this same composition is associated with the Glu-A1c and Glu-B1e and even poorer when associated with the Glu-A1c and Glu-B1f. In addition, the cultivars with B-LMW-GS allelic composition aab (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d, gave high quality, whereas when associated with the Glu-A1c and Glu-B1e or with Glu-A1o and Glu-B1f, the quality was very poor.     

Effect of high molecular weight glutenins and rye translocations on soft wheat flour cookie quality

The influence of high molecular weight glutenin subunits (HMW-GS) on wheat breadmaking quality has been extensively studied but the effect of different Glu-1 alleles on cookie quality is still poorly understood. This study was conducted to analyze the effect of HMW-GS composition and wheat-rye translocations on physicochemical flour properties and cookie quality of soft wheat flours. Alleles encoded at Glu-A1, Glu-B1 and Glu-D1 locus had a significant effect over physicochemical flour properties and solvent retention capacity (SRC) profile. The null allele for Glu-A1 locus presented the highest cookie factor observed (CF = 7.10), whereas 1BL/1RS and 1AL/1RS rye translocations had a negative influence on CF. The three cultivars that showed the highest CF (19, 44 and 47) had the following combination: Glu-A1 = null, Glu-B1 = 7 + 8, Glu-D1 = 2 + 12 and no secalins. Two prediction equations were developed to estimate soft wheat CF: one using the HMW-GS composition and the other using physicochemical flour parameters, where SRCsuc, SRC carb, water-soluble pentosans, damaged starch and protein turned out to be better CF predictors. This data suggests that grain protein allelic composition and physicochemical flour properties can be useful tools in breeding programs to select soft wheat of good cookie making quality.     

Effect of high molecular weight glutenins and rye translocations on soft wheat flour cookie quality

The influence of high molecular weight glutenin subunits (HMW-GS) on wheat breadmaking quality has been extensively studied but the effect of different Glu-1 alleles on cookie quality is still poorly understood. This study was conducted to analyze the effect of HMW-GS composition and wheat-rye translocations on physicochemical flour properties and cookie quality of soft wheat flours. Alleles encoded at Glu-A1, Glu-B1 and Glu-D1 locus had a significant effect over physicochemical flour properties and solvent retention capacity (SRC) profile. The null allele for Glu-A1 locus presented the highest cookie factor observed (CF = 7.10), whereas 1BL/1RS and 1AL/1RS rye translocations had a negative influence on CF. The three cultivars that showed the highest CF (19, 44 and 47) had the following combination: Glu-A1 = null, Glu-B1 = 7 + 8, Glu-D1 = 2 + 12 and no secalins. Two prediction equations were developed to estimate soft wheat CF: one using the HMW-GS composition and the other using physicochemical flour parameters, where SRCsuc, SRC carb, water-soluble pentosans, damaged starch and protein turned out to be better CF predictors. This data suggests that grain protein allelic composition and physicochemical flour properties can be useful tools in breeding programs to select soft wheat of good cookie making quality.     

Relationships Between Chromosome 1B-encoded Glutenin Subunit Compositions and Bread-making Quality Characteristics of Some Durum Wheat (Triticum turgidum) Cultivars

The high and low M_r glutenin subunit compositions (controlled by the Glu-1 loci and the Glu-B3 locus, respectively) and the bread-making quality characteristics of 26 durum wheat (Triticum turgidum) genotypes were determined. The relationships between quality parameters and Glu-B1 and Glu-B3 controlled glutenin subunit composition were also investigated. The Glu-A1-controlled null allele was present in all the genotypes. High M_r subunits 20, 6 + 8 and 7 + 8 occurred in similar proportions in the cultivars analysed. The Glu-B3 low M_r allelic variants, LMW-1 and LMW-2, were both represented, with LMW-1 being present in lower proportion. Flour protein, SDS-sedimentation volume, dough strength (Alveograph W value), dough mixing time and bread loaf volume varied among the genotypes. Most samples had high Alveograph tenacity/extensibility (P/G) ratios, typical of tenacious gluten character. SDS-sedimentation volume, dough strength, dough mixing time and bread loaf volume were all interrelated. An association with flour protein content was observed only for mixing time, while the Alveograph tenacity/extensibility ratio was not correlated with the other parameters. Comparisons within the Glu-B1 and Glu-B3 loci indicated that the high M_r subunit 7 + 8 and the low M_r subunit LMW-2 had significantly greater beneficial effects on gluten strength and bread-making quality than the high M_r subunits 6 + 8 or 20 and the low M_r subunit LMW-1, respectively. High M_r subunit 6 + 8 had greater beneficial effects on quality than subunit 20.     

Effect of Allelic Variation of Glutenin Subunits and Gliadins on Baking Quality in the Progeny of Two Biotypes of Bread Wheat cv. Ulla

During the determination of the HMW glutenin subunit composition of Finnish varieties, the variety Ulla was observed to contain two biotypes which differed from each other at two loci:Glu-A1andGlu-A3/Gli-A1. One of them, called Ulla 1, contained subunit 2* (Glu-A1b) andGlu-A3o/Gli-A1o, and Ulla 2 contained the null allele (Glu-A1c) andGlu-A3a/Gli-A1c. In order to determine the effect of this allelic variation on quality, the two biotypes were crossed and random lines were produced from the progeny by single seed descent. In total, 95 F6 lines were analysed from four bulked Ulla progeny lines. Significant interaction between the allelic variants of HMW glutenins and LMW gluten proteins affected the SDS-sedimentation volume at the mean flour protein level of 13·1% (dmb); the effect of LMW gluten variants was larger in the lines deficient of a HMW glutenin subunit than in lines having a HMW glutenin subunit (2*). At the higher flour protein levels (mean=15·1%, dmb) the effect on SDS-sedimentation volume was additive; progeny carrying alleles b (subunit 2*) and o/o atGlu-A1andGlu-A3/Gli-A1had significantly greater sedimentation volumes than the progeny carrying alleles c (no subunit) and a/c, respectively. The SDS-sedimentation volumes indicated differences in the quantities of the polymeric glutenins, gel proteins which have been shown to reflect dough strength. In the four bulked Ulla progeny lines, the variation in HMW glutenin subunits affected the dough strength values of the Extensigraph. However, the variation in LMW glutenin subunits did not affect Extensigraph dough strength values, as was predicted by SDS-sedimentation volumes. In the Ulla progeny, adding a HMW glutenin subunit affected Extensigraph dough strength more than adding a LMW glutenin subunit, although both increased the SDS-sedimentation volumes. Moreover, the variation in LMW gluten proteins affected the dough mixing stability in the Farinograph and test baking results of the Ulla progeny.     

黄淮麦区小麦品种高分子量谷蛋白亚基组成分析

对黄淮麦区育成推广品种(59个)、2003～2004年度国家黄淮南片和江苏省区试参试品种(42个)、徐州农科所育成的高代品系以及一些育种亲本材料,共计309个品种(材料)的高分子量谷蛋白亚基组成进行了分析.结果共发现了32个亚基组成类型和16个等位基因变异.在Glu-A1位点发现了Glu-A1a、Glu-A1b、Glu-A1c 3个等位基因;在Glu-B1位点发现了Glu-B1a、Glu-B1b、Glu-B1c、Glu-B1d、Glu-B1e、Glu-B1f、Glu-B1g、Glu-B1h、Glu-B1i、Glu-B1k共10个等位基因;在Glu-D1位点发现了Glu-D1a、Glu-D1b、Glu-D1d 3个等位基因.以Glu-B1位点的变异最为丰富.在这3个位点上分别以等位基因Glu-A1c(null)、Glu-B1b(7 8)和Glu-D1a(2 12)为主,其出现频率分别为58.58%、58.90%和77.99%.高分子量谷蛋白亚基组成以(null,7 8,2 12)和(1,7 8,2 12)为主,分别占所有品种的32.69%和16.18%.在育成推广品种和参试品种中,等位基因变异均为11个;而亚基组成类型则分别为16个和13个.优质高分子量谷蛋白亚基5 10在所有材料、59个已审定推广品种和42个参试品种中的出现频率分别为20.4%、27.1%%和21.4%,频率均较低.这表明新近育成的品种在优质亚基的构成上并未取得较大进展,优质强筋小麦的品质育种还有较大的发展空间.试验结果也表明,黄淮冬麦区小麦品种的高分子量谷蛋白亚基组成类型和等位基因变异较为丰富,但其变异分布很不均匀,存在明显的优势亚基和组成类型.     

Glutenin subunit compositions and breadmaking quality characteristics of synthetic hexaploid wheats derived from Triticum turgidum × Triticum tauschii (coss.) Schmal Crosses

The Glu-B1, Glu-D1 and Glu-B3 encoded glutenin subunit compositions of a population of synthetic hexaploid wheats (AABBDD, 2n=6x=42), which was random for flour protein (FP), SDS-sedimentation (SDSS), Alveograph strength (W), the tenacity/extensibility (P/G) ratio and bread loaf volume (LV) were examined in this study. The synthetics were produced from various crosses involving several Triticum lurgidum cultivars and Triticum lauschii (coss.) Schmal accessions. The Glu-A1 null allele as well as three Glu-B1 (subunits 7 + 8, 6 + 8 and 20), 13 Glu-D1 and two Glu-B3 (LMW-1 and LMW-2) allelic variants were present in the synthetic population. Thirty-six different glutenin subunit combinations, including the Glu-B1, Glu-D1 and Glu-B3 encoded alleles, were observed. The synthetic hexaploids showed large variations for all quality parameters evaluated. All quality characteristics except one (P/G ratio, which showed no association with allelic variations at Glu-B3) were influenced by allelic variations at the Glu-B1 and Glu-B3 loci; subunits 6 + 8 and 7 + 8 showed significantly better quality effects than subunit 20. Low M_r glutenin subunits LMW-1 and LMW-2 showed both negative and positive quality effects. The Glu-D1 locus of T. tauschii contributed various alleles not found in bread wheat. The influence of new Glu-D1 alleles on the bread-making quality characteristics of the synthetic wheats could not be established, partly because there was a limited frequency of some of the alleles in the population, and partly because some synthetics, having a common Glu-D1 allele, showed quality differences associated with allelic variation at Glu-B1 and/or Glu-B3. Differential quality effects could be observed, however, among some Glu-D1 alleles. Synthetics derived from a common durum wheat source showed better overall quality characteristics and bread loaf volume when they possessed subunits 5 + 12 or 1·5 + 10 than when they had any other Glu-D1 encoded glutenin subunit.     

Effect of allelic variation at the Glu-3/Gli-1 loci on breadmaking quality parameters in hexaploid wheat (Triticum aestivum L.)

Low molecular weight glutenin subunits (LMW-GS) encoded by the Glu-3 loci are known to contribute to wheat breadmaking quality. However, the specific effect of individual Glu-3 alleles is not well understood due to their complex protein banding patterns in SDS-PAGE and tight linkage with gliadins at the Gli-1 locus. Using DNA markers and a backcross program, we developed a set of nine near isogenic lines (NILs) including different Glu-A3/Gli-A1 or Glu-B3/Gli-B1 alleles in the genetic background of the Argentine variety ProINTA Imperial. The nine NILs and the control were evaluated in three different field trials in Argentina. Significant genotype-by-environment interactions were detected for most quality parameters indicating that the effects of the Glu-3/Gli-1 alleles are modulated by environmental differences. None of the NILs showed differences in total flour protein content, but relative changes in the abundance of particular classes of proteins cannot be ruled out. On average, the Glu-A3f, Glu-B3b, Glu-B3g and Glu-B3i_Man alleles were associated with the highest values in gluten strength-related parameters, while Glu-A3e, Glu-B3a and Glu-B3i_Chu were consistently associated with weak gluten and low quality values. The value of different Glu-3/Gli-1 allele combinations to improve breadmaking quality is discussed.     

Development of introgression lines with 18 alleles of glutenin subunits and evaluation of the effects of various alleles on quality related traits in wheat (Triticum aestivum L.)

In this report, we present a set of 104 ILs with 18 alleles for five glutenin loci. They were developed from crossing and backcrossing 64 varieties as donor parents to Yanzhan 1 as recurrent parent. The effects of the 18 alleles on nine dough quality parameters were evaluated in a similar background using these lines. The results showed that Glu-A1a produced the highest SDS-sedimentation volume (Ssd), midline time x=8 width (MTxW), mixing tolerance (MT) and the lowest weakening slope (WS). At the Glu-B1 locus, Glu-B1f produced the highest values for all quality parameters but WS. At the Glu-D1 locus, Glu-D1d was the best for Ssd, grain hardness (GH), midline peak width (MPW), MTxW and MT. The positive effects of Glu-B1f on GH and Glu-B3b on Ssd were mainly from the effect of GPC. Overall, 5 interactive loci and 13 interactive alleles were found to be significant. No negative interaction between high quality glutenin alleles was detected. The preferred allele combinations for breeding were recommended based on the additive and interactive effects. Our results suggest that the ILs with multiple alleles are ideal genomic stocks for evaluating the effects of alleles on some traits and for pyramiding favorable alleles in breeding wheat varieties.     

青海高原春小麦HMW—GS等位基因变异及其对面团流变学特性的作用

为了给青海高原春小麦改良提供资料。分析了青海育成和国内外引进的125个春小麦品种(系)的HMW—GS等位基因变异。并测定了其中58个品种(系)在青海高原环境下的面团流变学特性。结果表明：(1)参试春小麦品种(系)的HMW—GS存在广泛的变异。Glu—A1位点出现3个等住基因，Glu—B1住点出现5个等住基因，Glu—D1位点出现4个等位基因；共出现了22种HMW—GS组合形式。其中1.7 8.2 12和N，7 8，2 12组合类型出现频率最高。并发现了个别罕见的变异类型，如2 10，10。(2)亚基组合类型对沉淀值、形成时间、稳定时间、评价值等品质性状影响较大，对籽粒蛋白质含量、出粉率和面粉吸水率的影响不显著。试验还表明，HMW—GS组成与面粉的筋力有密切关系。     

Effect of β-glucans on viscoelastic properties of barley kernels and their relationship to structure and soluble dietary fibre

The stress relaxation behaviour of barley kernels with differences in β-glucan was studied using the generalized Maxwell model for explaining the differences in quality. The relaxation moduli show that cultivar significantly affected the relaxation times (τ₂ and τ₃) and compressional viscosity (η_E2 and η_E3) of the 3 Maxwell elements and the pure elastic component (E₀). These data were twice as high in cultivars with high β-glucans compared to low β-glucans. Protein and malt extract, as well as β-glucan, showed similar patterns to the corresponding cultivars from the same locations. Malt extract was correlated with both insoluble fibre (−0.71; P < 0.0007) and total fibre (−0.66; P < 0.006). High β-glucan cultivars presented relatively high soluble fibre, wort viscosity and presented higher relaxation times. Soluble fibre and the wort viscosity were correlated with relaxation times τ₁, τ₂, τ₃. Also, β-glucans were correlated with τ₃ and viscosity η_E3. The overall importance of the effect of β-glucans on viscoelasticity, malting and food quality as shown in this investigation is in agreement with earlier investigations.     

Effect of β-glucans on viscoelastic properties of barley kernels and their relationship to structure and soluble dietary fibre

The stress relaxation behaviour of barley kernels with differences in β-glucan was studied using the generalized Maxwell model for explaining the differences in quality. The relaxation moduli show that cultivar significantly affected the relaxation times (τ₂ and τ₃) and compressional viscosity (η_E2 and η_E3) of the 3 Maxwell elements and the pure elastic component (E₀). These data were twice as high in cultivars with high β-glucans compared to low β-glucans. Protein and malt extract, as well as β-glucan, showed similar patterns to the corresponding cultivars from the same locations. Malt extract was correlated with both insoluble fibre (−0.71; P < 0.0007) and total fibre (−0.66; P < 0.006). High β-glucan cultivars presented relatively high soluble fibre, wort viscosity and presented higher relaxation times. Soluble fibre and the wort viscosity were correlated with relaxation times τ₁, τ₂, τ₃. Also, β-glucans were correlated with τ₃ and viscosity η_E3. The overall importance of the effect of β-glucans on viscoelasticity, malting and food quality as shown in this investigation is in agreement with earlier investigations.     

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.     

中国小麦品种高分子量谷蛋白亚基和低分子量谷蛋白亚基组成分析

为给我国优质小麦品种的选育和改良提供科学依据,应用SDS-PAGE方法对我国235份推广品种和高代品系的HMW-GS和LMW-GS组成与分布进行了分析。结果表明,HMW-GS和LMW-GS分别具有39和40种带型组合;5个位点共发现34个等位基因。Glu-A1、Glu-B1和Glu-D1分别有3、8和6个变异位点;亚基1、Null、7＋9、5＋10和2＋12是主要的HMW-GS类型,频率分别为46．2％、46．2％、44．5％、47．0％和48．3％。Glu-A3和Glu-B3位点（本文不涉及Glu-D3）分别具有6和11个变异位点。Glu-A3c、Glu-A3d、Glu-B3e和Glu-B3j是主要的LMW-GS类型,频率分别为55．1％、21．6％、28％和28．8％。本研究还发现,在品种Z75和绵阳96-319的Glu-D1位点上,亚基组合形式为5＋12;在品种周92034的Glu-D1位点,亚基组合形式为2＋10。虽然这两种组合形式在本研究中出现的频率很低,但这两种亚基组合在以前的研究中很少出现。     

Purification of wheat flour high-molecular-weight glutenin subunits by fast protein liquid chromatography

Fast protein liquid chromatography has been developed for purification of high-molecular-weight glutenin subunits HMW-GSs from wheat flour. Flour samples from four wheat cultivars with different HMW-GS alleles at Glu-A1, Glu-B1 and Glu-D1 loci were used to establish the method. The column material used was Resource™ Phe, and the optimal elution was with a gradient formed with buffer A [0.05 M Tris–HCl containing 4 M urea and 0.25 M (NH₄)₂SO₄, pH 8.0] and buffer B [0.05 M Tris–HCl containing 4 M urea (pH 8.0)] at a flow rate of 0.5 ml/min. A pure single 1Dx-, 1Bx- HMW-GS, and all the y-type HMW-GSs present in one genotype can be reliably separated in a single step.     

Comparative analyses of LMW glutenin alleles in bread wheat using allele-specific PCR and SDS-PAGE

One hundred and eighty-two bread wheat cultivars developed in India were characterized for low molecular weight (LMW) glutenins using SDS-PAGE and allele-specific polymerase chain reaction (PCR) to assess allelic diversity encoded by Glu-3 loci, as well as their utility for correctly identifying different alleles. SDS-PAGE indicated Glu-A3c is present in 64.6% of the cultivars, Glu-A3b in 13.8%, Glu-A3d in 12.7% and Glu-A3e/f in 8.8%. Seven types of alleles were present at the Glu-B3 locus: Glu-B3b (29.3%), Glu-B3g (27.0%), Glu-B3h (13.8%), Glu-B3i (16.1%), Glu-B3j (12.1%), Glu-B3c (0.6%) and Glu-B3d (1.1%). SDS-PAGE found three types of Glu-D3 alleles: Glu-D3a (30.2%), Glu-D3b (67.1%) and Glu-D3c (2.7%). However, PCR found two different alleles in cultivars classified as carrying Glu-D3a and three alleles in those identified as carrying Glu-D3b cultivars, indicating a more complex nature of the Glu-D3 locus. In conclusion, the data found greater consistency between the SDS-PAGE and PCR amplification patterns of alleles such as Glu-A3c, Glu-A3d, Glu-B3g, Glu-B3h and Glu-B3i, and less consistency between those same patterns in the Glu-A3b, Glu-A3e/f and Glu-B3b alleles. More studies are needed in order to achieve unambiguous identification of the Glu-3 alleles and thereby allow their greater utility in germplasm evaluation and breeding.