The dynamic rheological properties of glutens and gluten sub-fractions from wheats of good and poor bread making quality

The dynamic rheological properties of glutens and gluten fractions (gliadin and glutenin) of two U.K.-grown wheat cultivars, Hereward and Riband, having good and poor bread quality, respectively, were studied. Gluten and glutenin doughs from cv. Hereward had higher G' and lower tan δ values than those from cv. Riband at all frequencies studied. A more pronounced difference in G' and tan δ was observed between the glutenin doughs of the two wheats than between their respective gluten doughs. The rheological properties, i.e. G' and tan δ values, of gliadin doughs were similar for both wheats. Varying the gliadin/glutenin ratio by adding the isolated gliadin or glutenin sub-fractions to the parent glutens showed that the G' values decreased and the tan δ values increased as the gliadin/glutenin ratio was increased for both cultivars, indicating a considerable decrease in elasticity as the gliadin/glutenin ratio increased. The decrease in G' may be attributed to a plasticising effect of gliadin and ‘interference’ of gliadin with glutenin-glutenin interactions. The reduction in G' was much more pronounced when the gliadin/glutenin ratio was increased between 0.15 and 1.0 than between 1.0 and above. Gluten from cv. Hereward had higher G' and lower tan δ values than cv. Riband gluten at all gliadin/glutenin ratios, indicating that cv. Hereward gluten had greater elastic character than cv. Riband gluten. Although significant effects of other non-protein hydrocolloid components cannot be discounted, these observations are consistent with the view that the viscoelasticity of the glutenin sub-fraction of gluten and differences in the ratio of gliadin to glutenin are the main factors governing inter-cultivar differences in the viscoelasticity of wheat gluten.     

施氮量对强筋小麦产量、氮素利用率和品质的影响

为探明协同提高强筋小麦产量、氮素利用率和品质的施氮量,以强筋小麦品种济麦20（中穗型）和洲元9369（大穗型）为材料, 研究了180、240和300 kg·hm^-2三个氮肥水平（分别用N180、N240和N300表示）对强筋小麦产量、氮素利用率、品质及其相关指标的影响。结果表明,相同施氮量下,洲元9369的产量、氮素利用率、面团形成时间、面团稳定时间、面包体积和面包评分均高于济麦20。当施氮量由N180增至N240时,2个品种的产量无显著变化,但沉降值、面团形成时间、面团稳定时间、面包体积和面包评分均显著提高;施氮量增至N300后,2个品种的产量和品质又都显著下降,籽粒总蛋白含量、谷蛋白含量、SDS-不可溶性谷蛋白含量、醇溶蛋白含量和谷蛋白聚合指数均明显降低,而SDS-可溶性谷蛋白含量和谷醇比却表现为上升趋势。经相关分析,SDS-不可溶性谷蛋白含量、谷蛋白聚合指数与面团形成时间、面团稳定时间、面包体积和面包评分均呈显著正相关。以上结果表明,谷蛋白聚合程度降低是过量施氮条件下强筋小麦品质下降的主要原因。综合考虑小麦产量、氮素利用率和籽粒品质,240 kg·hm^-2为本研究条件下的最佳施氮量。     

Towards a new gliadin reference material–isolation and characterisation

Twenty-eight wheat cultivars representative of the three main European wheat producing countries, France, UK and Germany, were selected as a source for the preparation of a reference gliadin. One kilogram of kernels from each cultivar were mixed and milled. The resulting white flour was defatted and vacuum dried. Albumins and globulins were eliminated by extraction using 0.4 M NaCl solution and gliadins were extracted with 60% ethanol. The gliadin extracts were concentrated, desalted by ultrafiltration, freeze-dried, and homogenised. After tests had shown good solubility and homogeneity, aliquots of the reference gliadin were sent to 16 different laboratories for further investigations: The material was analysed by various methods including RP-HPLC, SE-HPLC, RP-HPLC-ESI-MS, MALDI-TOF, capillary electrophoresis, acid-PAGE, 2D-PAGE, SDS-PAGE and immunoblotting and ELISA-tests with different monoclonal and polyclonal antibodies. The results showed that the gliadin composition of the source flour and the reference gliadin matched perfectly, demonstrating that no major gliadin components had been lost during the isolation procedure. The reference gliadin showed good immunochemical sensitivity with different gliadin antibodies in enzyme immunoassays. Because of its high protein and gliadin content, good solubility, homogeneity, stability and representative character, the product is regarded as a suitable universal reference material.     

抗赤霉病小麦地方品种的贮藏蛋白分析

采用A-PAGE和SDS-PAGE方法,对来自不同地方的23个抗赤霉病小麦地方品种的醇溶蛋白和谷蛋白亚基进行了分析。结果表明,在A-PAGE电泳分析中,23个供试品种具有23种不同的醇溶蛋白带型,共分离出39条相对迁移率不同的谱带,其中31条具有多态性,占86.8％,每份材料可电泳出14～23条带,存在着广泛的等位基因变异。在SDS-PAGE电泳分析中,出现了9种不同的高分子量谷蛋白亚基及6种亚基组合类型,优质亚基及亚基组合所占的比例较少,品质评分较低,其变幅为5～9分,平均为6.8分。     

Characterization of wheat gluten subunits by liquid chromatography – Mass spectrometry and their relationship to technological quality of wheat

The quality of common wheat is largely influenced by the composition of its storage proteins. The currently presented research explores factors influencing observed differences in quality and quantity between wheat cultivars, in particular in relation to gluten composition and its relationship to technological characteristics. Eight wheat cultivars (H. Wieser, Seilmeier, W., Belitz, H.D., 1994 Parsi, Sirvan, Sivand, Pishgam, Pishtaz)were selected for evaluation. Analysis results demonstrated that Morvarid and Sirvan cultivars yielded the highest quality of wheat, while the Chamran cultivar was indicated as the most favorable for baking Taftoon bread. Conversely, the Sepahan cultivar was deemed to have the worse quality in both categories. A Q Exactive LC-MS/MS system was employed to evaluate the most effective sub-fractions of gliadin and glutenin on wheat quality. Matching peptides resulting from trypsin digestion on gliadin and glutenin fractions, led to the identification of subunits α/β-gliadin, γ-gliadin, HMW-Dx5, HMW-Bx17, HMW-Dy3, HMW-Dy10, HMW-By15, LMW-m, LMW-s, and LMW-i. The obtained results indicated that the most influential subunits of glutenin on wheat quality were Dy10, Dy3 and Dx5, while the most effective gliadin subfraction was noted to be α/β-gliadin However, the most important subunit influencing the quality of flat breads in particular was identified as the x-HMW-GS, in particular the Bx17 subunit, and LMW-GS.     

Consistent differences among wheat cultivars in osmotic adjustment and their relationship to plant production

Osmotic adjustment (OA) is generally considered an important component of drought resistance. Several reports by J.M. Morgan [Morgan, J.M., 1983. Osmoregulation as a selection criterion for drought tolerance in wheat. Aust. J. Agric. Res. 34, 607–614; 1992. Osmotic components and properties associated with genotypic differences in osmoregulation in wheat. Aust. J. Plant Physiol. 19, 67–76; 1995. Growth and yield of wheat lines with differing osmoregulative capacity at high soil water deficit in seasons of varying evaporative demand. Field Crops Res. 40, 143–152; Morgan, J.M., Condon, A.G., 1986. Water-use, grain yield and osmoregulation in wheat. Aust. J. Plant Physiol. 13, 523–532] from Australia concluded that consistent genetic differences in OA existed among wheat cultivars and that high OA cultivars tended to yield better than low OA cultivars under drought stress. Our study was performed to assess his results with his and other genetic materials.Two of Morgan’s spring wheat lines with high OA (‘H.Osm-134’) and low OA (‘L.Osm-136’) capacity in addition to eight other diverse spring wheat cultivars were tested for OA and plant production when grown in small plots under a rain exclusion shelter at Bet Dagan, Israel in 1996. OA of five of these cultivars (including Morgan’s lines) was also measured in two independent greenhouse tests in 1997 (Israel) and 1998 (Texas).The five cultivars differed significantly and ranked consistently for OA in all tests. No significant cultivar by test interaction for OA was revealed. OA was well correlated across cultivars between tests. The significantly higher OA capacity of H.Osm-134 as compared with L.Osm-136 was repeated in all tests. OA of all ten cultivars was positively correlated with biomass (r = 0.73; p = 0.02) and yield (r = 0.55; p = 0.09) under pre-flowering drought stress in the rain exclusion shelter. H.Osm-134 line performed significantly (p ≤ 0.05) better than L.Osm-136 line for both biomass and yield under drought stress. We therefore support Morgan’s results and conclude that consistent differences in OA exist among wheat cultivars and that these differences can be associated with plant production under pre-flowering drought stress.     

Effects of genetic improvements on grain yield and agronomic traits of winter wheat in the Yangtze River Basin of China

Wheat is an important food crop worldwide. Genetic improvements have contributed much to wheat production since the 1960s. Verifying the evolution of agronomic traits and the physiological basis of grain yield will facilitate breeders and agronomists in developing new wheat cultivars, with the aim of stable and high yields. Thirty-five wheat cultivars, bred or widely planted in the Yangtze River Basin from 1950 to 2005, were grown in field experiments under three N rates (0, 112.5, and 225 kg N ha⁻¹) from 2006 to 2009 in Nanjing, China. Wheat grain yield, kernels per spike, 1000-kernel weight (TKW), and harvest index (HI) increased linearly with cultivar development from the 1950s to the 2000s, whereas spikes per unit land decreased significantly with cultivar development during the same period, and stabilized with further genetic improvements in cultivars. Grain yield, kernels per spike, and TKW differed with N rate and with cultivar. Grain yield, spikes per unit land, and kernels per spike increased significantly with increasing N fertilizer, but TKW and HI decreased. Cultivar height decreased with cultivar development from the 1950s to the 1980s, and remained relatively stable in subsequent cultivars. The proportion of the length of the top internode to total plant height increased with cultivar development from the 1950s to the 1980s and thereafter fell, while the length of the basal internode (BI) maintained a shortening trend. Leaf area per culm, leaf area index (LAI), net photosynthetic rate (Pn), and photosynthetic activity duration (PAD) of the flag leaf increased with cultivar development. Leaf area, LAI, and Pn increased significantly with increasing N fertilizer, while PAD did not. Single spike yield increased linearly with genetic development in cultivars, and these increases mainly resulted from increasing kernel number and weight, which were closely related to source size and cultivar. Grain yield was positively correlated to leaf area, LAI, Pn_Max, PAD, and single spike yield; single spike yield was positively correlated to leaf area, LAI, Pn_Max, and PAD, suggesting that grain yield improvements were mainly associated with improvements in the source (leaf area, LAI, Pn, PAD, etc.) and sink (single spike yield). Sink-source ratios increased with genetic development of cultivars, suggesting that productivity per leaf improved and that sink-source relationships have reached close to optimum in the Yangtze River Basin. Furthermore, breeding for high yield should be related to improvement in kernels per spike and TKW per unit land and increased sink-source ratios with a feasible LAI, and N fertilizer management should be considered during breeding for higher yields.     

Baking quality of emmer-derived durum wheat breeding lines

Durum wheat (Triticum turgidum L. var. durum) is used predominantly for pasta products, but there is increasing interest in using durum for bread-making. The goal of this study was to assess the bread-making potential of 97Emmer19, an Emmer wheat (Triticum turgidum L. var. dicoccum) and in breeding lines derived from crosses of 97Emmer19 with adapted durum wheat cultivars. 97Emmer19 and its progeny were evaluated in 2005 and 2006 along with five durum wheat cultivars. Three bread wheat (Triticum aestivum L.) cultivars were included as checks to provide a baseline of bread making quality observed in high quality bread wheat cultivars. 97Emmer19 exhibited higher LV than all the durum wheat checks and approached the LV achieved with the bread wheat cultivar ‘AC Superb’. Breeding lines derived from 97Emmer19 had higher LV than those of the durum wheat checks, confirming that this trait was heritable. In general, durum wheat cultivars with elevated gluten strength and/or increased dough extensibility were noted to have higher LV. Dough extensibility appeared to be a more critical factor as gluten strength increased. These results indicate that there is potential to select for genotypes with improved baking quality in durum breeding programs.     

99份国内小麦新品种（系）醇溶蛋白的遗传多样性分析

为了解目前普通小麦育成品种（系）间醇溶蛋白的遗传多样性,利用酸性聚丙烯酰胺凝胶电泳（Acid polyacrylamide gel electrophoresis, APAGE）技术对国内99份小麦新品种（系）进行了醇溶蛋白分析。结果表明,供试材料中共分离出蛋白带2 192条,迁移率不同的谱带类型106种,其中迁移率编号为9和11的2种谱带出现频率最高,均为82.11%;有38条谱带的出现频率低于10%,这些低频率谱带仅出现在极少数的材料中;其余66条谱带出现频率为10.53%~64.21%,具有较高的多态性。每个被检测材料可电泳分离出15 ~ 30条带,其中大部分为18 ~ 24条。供试材料间遗传距离（Genetic distance, GD）为0.07 ~ 0.73,平均为0.59,遗传变异较大。聚类分析可将其分为4大类。与过去的小麦品种醇溶蛋白研究结果相比,新品种（系）的平均遗传距离缩小,遗传基础变窄。     

Damage Potential,Effect on Germination,and Development of Sitophilus oryzae (Coleoptera: Curculionidae) on Wheat Grains in Northwestern Himalayas

The present investigation was carried out to study the biological parameters and orientation of Sitophilus oryzae (L.) toward wheat cultivar HPW-236 and mixed grains of different cultivars (HPW-155, HPW-236, HPW-249, HPW-349, HPW-360, HS-490, and VL-892). The incubation period, larval period, pupal period, and total life cycle period of S. oryzae was longer when fed on mixed grains as compared to HPW-236. Also, the weevils were more oriented toward HPW-236 and lower germination rates were observed from HPW-236 than mixed cultivars when exposed to S. oryzae. We also evaluated quantitative losses caused by S. oryzae in different cultivars of wheat recommended in the northwestern Himalayas under free-choice conditions. The weevil inflicted greater damage and weight loss in grains of HPW-236 while it was negligible in the case of HPW-360 and HPW-249. HPW-236 which is the most cultivated variety of wheat in northwestern Himalayas proved to be highly susceptible to the weevil and provided a more suitable environment for weevil’s development. Therefore, this particular cultivar can be avoided for prolong storage and the farmers should prefer cultivars such as HPW-360 and HPW-249, which proved to be least affected the weevil.     

Potassium phosphate induces tolerance against the Russian wheat aphid (Diuraphis noxia,Homoptera: Aphididae) in wheat

Diuraphis noxia Kurdjumov is an aphid pest that hampers the global production of wheat (Triticum aestivum L.). Infestation of wheat by D. noxia reduces crop yield and sometimes leads to the death of susceptible cultivars. To date resistant cultivars have been used to control infestations. However, the development of resistance-breaking aphid biotypes is complicating this management strategy. This study aimed to ascertain the effect that 25 mM potassium phosphate (K₃PO₄) treatment has on inducing resistance in wheat against D. noxia. The effects of potassium phosphate on induced resistance against D. noxia were determined using gene regulation and enzymatic levels of lipoxygenase (EC 1.13.11) and phenylalanine ammonia lyase (EC 4.3.1.24). The results indicated that the treatment of both susceptible (Scheepers) and resistant (Tugela DN) wheat cultivars with potassium phosphate induces genes differentially. A phenotypic study showed delayed development and less severity of symptoms with decreased numbers of aphids feeding on plants treated with potassium phosphate in comparison with untreated plants for both resistant and susceptible cultivars. The results from the gene expression and enzyme activity studies indicated that both of the induced systemic resistance-linked genes were similarly regulated after potassium phosphate treatment. The data strongly support treatment of wheat with potassium phosphate to induce tolerance against D. noxia.     

A novel enzyme-linked immunosorbent assay for the detection of Wx-B1 null wheat lines using a monoclonal antibody and its application for the detection of marker heterogeneity within commercial cultivars

A monoclonal antibody was raised with specificity for the granule bound starch synthase (GBSS1) Wx-B1 homeoallele of wheat (Triticum aestivum L.) using a synthetic peptide immunogen. This was used to develop a simplified enzyme-linked immunosorbent assay (ELISA) for the discrimination of Wx-B1a and Wx-B1b alleles which differ in the starch properties they confer. Discrimination of these alleles is important for the selection of wheat lines for Udon-style noodle production. The simplified ELISA worked in a single antibody (indirect) format and gave improved ease of use, discrimination of alleles and resolution relative to a previously developed 2-antibody (sandwich) ELISA. When the test was validated using breeders seed of a panel of commercial cultivars, heterogeneity of Wx-B1 alleles was observed for a significant proportion of the cultivars tested and this was confirmed using PCR analysis of the Wx-B1 and Wx-A1 genes. This observation has implications for cultivar wheat quality assessment, the application of molecular markers for variety identification purposes and the establishment of mapping populations from commercial cultivars.     

A novel hardness-related and starch granule-associated protein marker in wheat: LMW-GS-‘S’

Starch granule (SG)-associated proteins are involved in starch synthesis and the interaction between SGs and the endosperm protein matrix. In this study, SG proteins were sequentially extracted with the chaotropic reagent, urea from 1 M to 4 M, and then profiled using an integrated proteomic approach including one- and two-dimensional electrophoresis, mass spectrometry and antibody-based enzyme-linked immunosorbent assay (ELISA). The results demonstrated that the SG-associated proteins were dominated by granule-bound starch synthase (GBSS), gliadin, low molecular weight glutenin subunits (LMW-GS), serine protease inhibitors, α-amylase inhibitors and puroindolines. A protein with an apparent molecular mass of 50 kDa, expressed in cultivar hard wheat Kukri but not in soft wheat Triller was identified as a novel member of the ‘S’ group of LMW-GS, designated as LMW-GS-‘S’. Further characterization using a broad wheat population revealed that LMW-GS-‘S’ was selectively expressed in hard wheat cultivars while deleted in all soft wheats tested. Its relationship with hardness was confirmed by its expression in tetraploid durum wheats, which are among the hardest wheats around the world. Monoclonal antibody (MAb) F8-14E6 against LMW-GS-‘S’ was developed and used in an ELISA to screen 90 Glu allele-defined doubled haploid Janz/Kukri wheat lines. The allele that encodes LMW-GS-‘S’ was mapped to GluB3h (p < 0.001).     

蛋白质含量不同的春小麦开花后籽粒内源激素的变化

利用蛋白质含量和产量不同的３个春小麦品种,在盆栽条件下,研究了开花后籽粒内源激素活性的变化方式,结果表明：３个品种籽粒发育期间ｉＰＡ含量变化方式基本一致,但低蛋白品种出现峰值后,下降的速率明显高于高蛋白品种,而且含量最低水平的出现时期比高蛋白品种提前１０ｄ;ＧＡ含量变化呈双峰曲线,ＩＡＡ含量为单峰曲线;高蛋白品种的ＩＡＡ峰植显著高于其他两个品种,而低蛋白品种的ＡＢＡ峰植显著高于高蛋白品种。初步认为     

青海小麦籽粒硬度等位变异研究

为了解小麦品种籽粒硬度的遗传多样性,利用单粒谷物硬度测定、PCR扩增和核苷酸测序技术,分析了66份青海小麦品种籽粒硬度主效基因的等位变异。结果表明,青海小麦以硬质类型为主,比例达到47.0%,混合麦比例为19.7%,软质麦比例为33.3%。硬度基因有5种组合类型:野生型、Pina-D1a/PinbD1b、Pina-D1a/Pinb-D1c、Pina-D1a/Pinb-D1x和Pina-D1b/Pinb-D1a。野生型小麦类型比例最高,占59.09%,SKCS硬度指数平均为44.12,变化范围为12.75~84.89。突变类型的品种籽粒均为硬质。因此,在青海硬质小麦可以通过突变类型的分子标记进行选育,软质小麦选育需在利用硬度基因分子标记筛选的基础上进一步考察籽粒硬度性状的表现型。     

Effects of Fusarium culmorum and water stress on durum wheat in Tunisia

The effects of water stress on Fusarium foot and root rot in durum wheat were investigated in growth chamber, greenhouse and field tests in Tunisia. In the seedling stage, emergence of six durum wheat cultivars in the growth chamber was significantly reduced by inoculation with Fusarium culmorum and water stress (P<0.0001), with more disease under drier conditions. Additionally, the tiller number per mature plant, the 1000 grain weight and disease severity in mature stage were reduced by inoculation in greenhouse studies. In a field test, inoculation with F. culmorum significantly reduced the yield (P<0.001), by more than 17% for Om Rabiaa and 38% for Karim, the two cultivars tested. Yield was also significantly affected by precipitation and irrigation levels. The severity of the disease, estimated by the percentage of white heads, was separately affected by the cultivar (P<0.001) and inoculation (P = 0.0004). Percentage of white heads was 1.5 and 2 × higher in inoculated plants than non-inoculated for Om Rabiaa and Karim cultivars, respectively. Disease severity was highest in treatments with the greatest water stress. This is the first detailed study of water stress and F. culmorum on durum wheat in Tunisia, and indicates that cultivar resistance and irrigation management may be important in the management of Fusarium foot rot.     

宁夏小麦黄色素含量相关基因的组成与分布

选育低黄色素含量品种是宁夏小麦品质改良的重要目标之一。为阐明宁夏小麦中控制籽粒黄色素含量基因TaZds-A1和TaZds-D1的组成及分布特点,利用其功能标记YP2A-1和YP2D-1对91份小麦品种进行检测与分析。结果表明,在TaZds-A1位点,等位变异TaZds-A1a(与低黄色素含量相关)和TaZdsA1b(与高黄色素含量相关)分别占59.3%和40.7%;在TaZds-D1位点,等位变异TaZds-D1a(与高黄色素含量相关)占95.6%,TaZds-D1b(与低黄色素含量相关)仅占4.4%。宁夏小麦黄色素含量基因位点存在4种等位变异组合类型:以TaZds-A1a/TaZds-D1a(57.1%)组合类型为主,TaZds-A1b/TaZds-D1a(38.5%)组合类型次之,TaZds-A1a/TaZds-D1b和TaZds-A1b/TaZds-D1b组合类型最低(2.2%);不同等位变异组合类型在不同地区间的分布比例也不同。     

Fungal diseases of spring wheat in central Saudi Arabia

Fungal diseases of spring wheat (Triticum aestivum L.) in Central Saudi Arabia (AlGassim region) were surveyed in 1984 and 1985. Over 95% of the wheat fields were planted to the Yecora Rojo cultivar. Root and crown rots (Fusarium spp. and Helminthosporium spp.); brown root rot (Pythium spp.); leaf and head blotches (Helminthosporium spp.) and take-all (Gaeumannomyces sp.) were the most serious fungal diseases observed in the fields. Several H. sativum isolates were pathogenic to seedling leaves of most or all local and imported wheat cultivars (22 cultivars). Numerous soil-borne fungi were isolated from wheat roots and tested for pathogenicity to Yecora Rojo seedlings in the greenhouse. Alternaria sp., Helminthosporium spp. (two isolates), Fusarium spp. (three isolates), Pythium spp., Stemphylium spp. (two isolates) and Gaeumannomyces sp. were pathogenic to the inoculated wheat plants in the greenhouse.     

The impact of Septoria tritici blotch in bread making quality among argentinean wheat cultivars

Septoria tritici blotch (STB), caused by Zymoseptoria tritici is a relevant foliar wheat disease worldwide. Several reports show the importance of STB on grain yield, their components and grain protein while little is known about its effect on the rheological properties of the wheat flour. The scarce literature found, only mentions the effect of the complex of foliar diseases on wheat quality, without individualizing the effect of the different pathogens separately. This study analyze the influence of increasing doses of inoculum of Zymoseptoria tritici, on the bread making quality of ten Argentinean wheat cultivars and its possible variation according to their quality group. The increase of inoculum concentration augmented the area under disease progress curve, decreased green flag leaf area duration and green leaf area duration. Cultivars K. Flecha and B.75 Aniversario had the lowest green flag leaf area duration causing higher reduction in grain filling period and higher reductions in P, indicating a lower gliadin/glutenin ratio. STB decreased P/L and E while L, W, D, SV and bread volume increased. Cultivars differed in rheological parameters according to their quality group. Gluten/protein relationship was significant in quality group 1 and non-significant in cultivars belonging to quality group 2 and 3.