Phenolics in the bran of waxy wheat and triticale lines

The present study was designed to determine total phenolic acid contents (TPC) and compositions of bran from newly developed near-isogenic waxy wheat and triticale translocation lines. Two waxy wheat sets, Svevo (durum) and N11 (bread wheat), consisting of partial and waxy null lines and four sets of triticales (GDS7, Trim, Rhino and Rigel) having translocations at 1A.1D and 1R.1D with high molecular weight glutenin subunits (HMW-GS) 5 + 10 and 2 + 12 were investigated. Similar to non-waxy wheat, ferulic acid was the predominant phenolic acid found in waxy wheats analyzed. Two other major phenolics include p-coumaric and vanillic acids followed by lesser quantities of syringic acid. Waxy lines had higher TPC than the parent line in the N11 set, whereas the Svevo set showed the opposite trend. TPC of waxy bread wheats were correlated with amylose fractions in which the order was complete waxy < double waxy nulls < single waxy nulls. Lines with HMW-GS 2 + 12 have lower TPC than other lines in each group of triticales, except the Trim set. TPC was negatively correlated (r = −0.41; p > 0.1) with bran yields in triticale lines studied, indicating that variation in phenolics was not only due to bran yields but also to genotypic differences.     

Determination of phenolic acid concentrations in wheat flours produced at different extraction rates

High-performance liquid chromatography (HPLC) was used to determine the distribution of phenolic acids in wheat flours produced from five milling extraction rates ranging from 60% to 100% in four cultivars sown in two locations in the 2008–2009 season. Considerable variation was observed in free and bound phenolic acids, and their components in flours with different extraction rates. Most phenolic acids, including the component ferulic, were present in the bound form (94.0%). Ferulic (51.0%) was the predominant phenolic acid in wheat grain, and caffeic (22.8%) and p-coumaric (17.6%) acids were abundant. The phenolic acids and their components were all significantly influenced by effects of cultivar, milling, location, and cultivar × milling interaction, with milling effect being the predominant. The proportions of phenolic compounds varied considerably among milling extractions and cultivars, and their levels depended on both initial grain concentrations and on selection of milling extraction that was incorporated into the final product. The grain phenolic acid concentrations determined ranged from 54 μg g⁻¹ in flour produced at 60% extraction rate to 695 μg g⁻¹ in flour produced at 100% extraction rate, indicating their higher concentrations in bran associated with cell wall materials. Therefore, wholemeal wheat products maximize health benefits and are strongly recommended for use in food processing.     

Genome-wide association mapping of phenolic acids in tetraploid wheats

Phenolic acids are major components of cell walls in wheat and have important implications on human health as antioxidants with anti-tumor activity. Our objectives were to identify phenolic acid genes in wheat by single nucleotide polymorphisms (SNPs) detected within the coding sequences of candidate genes, and to identify chromosomal regions associated with single phenolic acids and total soluble phenolic compounds. A set of candidate genes involved in the biosynthesis of hydroxycinnamic acid derivatives were identified by comparative genomics. SNPs found in the coding sequences of six genes (PAL1, PAL2, C4H, C3H, COMT1 and COMT2) were used to determine their chromosomal location and accurate map position on two reference consensus linkage maps. The genome-wide association study (GWAS), based on genotyping a tetraploid wheat collection with 81,587 gene-associated SNPs, detected 22 quantitative trait loci (QTL) distributed on almost all durum wheat chromosomes. Two QTL for p-coumaric acid were coincident with the phenylalanine ammonia-lyase (PAL2) and p-coumarate 3-hydroxylase (C3H) genes on chromosome arms 2AL and 1AL, respectively. The availability of candidate gene-based markers can allow elucidating the mechanism of phenolic acids accumulation in wheat kernels and exploiting the genetic variability of phenolic acids content for the nutritional improvement of wheat end-products.     

Waxy endosperm accompanies increased fat and saccharide contents in bread wheat (Triticum aestivum L.) grain

The contents of fat, starch, pentosan, fructan, β-glucan and several mono- and oligosaccharides in grain were evaluated to find out the possible effects of the Wx-D1 gene of bread wheat using two sets of near-isogenic waxy and non-waxy lines and two low-amylose mutant lines with a common genetic background of Kanto 107. These materials have two non-functional Wx-A1b and Wx-B1b alleles in common. Waxy near-isogenic lines with a non-functional Wx-D1d allele showed consistently increased contents of fat, total fructan, β-glucan, glucose, fructose, sucrose, 1-kestose, 6-kestose, neokestose, nystose and bifurcose compared with non-waxy lines with a functional Wx-D1a allele throughout three growing/harvest seasons. Starch and total pentosan contents were inconsistently influenced by the allelic status of the Wx-D1 locus, while water-soluble pentosan and raffinose contents were not affected. The compositional changes of a low-amylose mutant line with an almost non-functional Wx-D1f allele were closely similar to those of waxy near-isogenic lines, while significantly different changes were barely observed in another low-amylose mutant line with a partly functional Wx-D1g allele in two seasons. These results showed that the Wx-D1 gene has pleiotropic effects on the fat and saccharide contents of bread wheat grain.     

小麦籽粒清蛋白和球蛋白条件和非条件QTL分析

小麦蛋白含量的提高对营养和加工品质具有重要的意义。本研究在2年3点6个环境下,以小麦品种“花培3号×豫麦57”构建的双单倍体（doubled haploid,DH）群体为材料,通过条件和非条件QTL鉴定与小麦开花后5个时期籽粒清蛋白和球蛋白含量积累有关的基因或数量性状基因座。结果表明,基于完备区间作图法,共检测到40个非条件QTLs和34个条件QTLs,单个位点的贡献率范围为6.44%~25.13%,其中QAlu1B-3在6个环境下的第4和第5时期均被检测出。本研究结果为了解不同灌浆期QTL选择性表达奠定了理论基础,检测到的QTL可能对小麦籽粒品质的提高有重要贡献。     

Phenolic Compounds in Wheat Grain Cultivars

Three hydroxybenzoic acids: p-hydroxybenzoic acid, vanillic acid and syringic acid; six hydroxycinnamic acids: p-coumaric acid, ferulic acid and four ferulic acid derivatives and a flavonoid (apigenin) were identified and quantified in 34 accessions corresponding to 19 cultivars of wheat applying HPLC coupled to diode array detector. Considerable differences between the wheat cultivars were observed in the phenolic contents. Some cultivars (Colorado, Del País, Barbilla, Jallado, Raspinegro Canario and Plaganudo) could be selected according to the high levels of phenolic compounds. Ferulic acid was the major phenolic acid compound followed by syringic and p-hydroxybenzoic acids. The proportion of ferulic acid present as dimeric forms ranged from 4.2 to 8.6% across all of the wheat cultivars analyzed. Apigenin, p-hydroxybenzoic and syringic acids did not show significant correlations. Many correlations between the determined hydroxycinnamic acids were observed. The ferulic acid and all the ferulic acid derivatives showed highly significant correlations, suggesting that the concentrations of diferulic acids depend on the concentration of ferulic acid.     

硬粒小麦和野生二粒小麦高分子量谷蛋白亚基的遗传多样性

为了解硬粒小麦和野生二粒小麦的高分子量谷蛋白亚基（HMWGS）组成及优质亚基的分布特点,并对其多样性进行分析,利用SDS聚丙烯酰胺凝胶电泳（SDSPAGE）对32份硬粒小麦和75份野生二粒小麦共107份材料的HMWGS组成进行了分析。结果表明,Glu1位点共有27种等位基因,其中GluA1位点4种,GluB1位点23种;亚基null和6+8在各自的位点上出现频率最高,分别达到38.84％和16.82％;其亚基组成类型共有47种,主要为1/6+8,频率达7.48％;同时筛选出33份含有1、2*、13+16、14+15、17+18等优质亚基的材料,可作为优质基因源。多样性分析结果表明,在GluA1和GluB1位点以及HMWGS组成上,野生二粒小麦的多样性都大于硬粒小麦。另外,在材料GW2、GW4中发现未命名的新亚基。     

四川小麦品种(系)淀粉颗粒结合蛋白多态性分析

为了解四川小麦品种(系)淀粉颗粒结合蛋白的多样性,对66份四川小麦地方品种、100份新育成品种(系)以及21份小麦骨干亲本材料的淀粉颗粒结合蛋白进行了SDS-PAGE分析。结果表明,在187份供试材料中共分离出7种蛋白条带组合类型,10种不同的蛋白条带,其中5种条带在供试材料中检测到缺失和迁移率改变。114份材料表现为SGP-1A蛋白缺失,而在所有供试的四川小麦地方品种中该蛋白均表达。共4份材料在SGP-1B位点蛋白迁移率改变,18份材料的Wx-1B蛋白条带缺失,8份材料的Wx-1D蛋白条带缺失,仅有1份材料的Wx-1A蛋白条带缺失。通过与中国春缺体-四体(N7AT7B、N7DT7B、N4AT4B)、乌拉尔图小麦(AA)、节节麦(DD)、圆锥小麦(AABB)淀粉颗粒结合蛋白的比较,并结合质谱鉴定,进一步验证了所鉴定条带的准确性。本研究表明,四川小麦新育成品种(系)和骨干亲本比四川小麦地方品种具有更丰富的淀粉颗粒结合蛋白变异类型,鉴定出的变异材料可用于淀粉颗粒结合蛋白功能的研究和小麦淀粉品质育种。     

Effects of microfluidization on antioxidant properties of wheat bran

Phenolic compounds present in native wheat bran are majorly bound to polysaccharides and entrapped in the fibre matrix. Recently, it was demonstrated that the microfluidization process could significantly improve physicochemical properties of wheat bran due to particle size reduction and microstructure modification. The current study provides further evidence that the process also significantly increased the contents of surface-reactive, alkaline and acid hydrolysable phenolics by 280%, 60% and 20%, respectively, after a total of 8 passes through the IC₂₀₀ and IC₈₇ chambers. Accordingly, the associated antioxidant capacity increased with increase in the extent of the treatment. However, there was a decrease in solvent extractable phenolic contents due to their dispersion in water and loss during the treatment. It is also worth noting that the residues after alkaline and acid hydrolysis still contained a high content of surface-reactive phenolics, which might indicate a significant underestimation of the total phenolic content and antioxidant capacity of wheat bran when using the conventional method based on solvent extraction and alkaline and/or acid hydrolysis.     

冀中南小麦新品系的高分子量麦谷蛋白亚基组成分析

为了解河北省小麦的品质遗传基础,采用SDS-PAGE电泳技术对2000~2003年度参加冀中南优质区试和普通区试小麦新品系的高分子量谷蛋白亚基(HMW-GS)组成进行了研究。结果表明,在这些品系中,G lu-1位点具有较为丰富的遗传变异,共检测到14种亚基和22种亚基组合类型;各年度普通区试优质亚基出现的频率分别为54.5%、66.7%、65%、100%,平均为71.4%,且有逐年上升的趋势;优质区试优质亚基出现的频率平均为159%,显著高于普通区试。试验还鉴定出一批含优质亚基的品系。     

Variation in polar lipid composition among near-isogenic wheat lines possessing different puroindoline haplotypes

The exact mechanism underlying wheat (Triticum aestivum L.) kernel hardness is unknown. Similar to puroindoline proteins, polar lipids are present on the surface of starch granules. The objective of this research was to determine the specific polar lipid species present on the surface of wheat starch from near-isogenic wheat lines that have different puroindoline haplotypes and endosperm hardness. Four near-isogenic wheat lines were used in this study, all derived from the soft cultivar Alpowa. Direct infusion tandem mass spectrometry was used to identify the lipid species in whole-meal, flour and starch samples. Endosperm hardness had no significant effect on the polar lipid contents in wheat whole-meal, a slight influence on the polar lipid contents of the flour fractions and a significant influence on the polar lipid composition of the polar lipids located on the surface of wheat starch. The greatest quantities of polar lipids on the starch-surface occurred when both puroindoline proteins were present in their wild-type form. Starch-surface polar lipid content dramatically decreased when one of the puroindoline proteins was null or if pin-B was in the mutated form. The least amount of polar lipids was present when pin-B was in its mutated form and pin-A was in its wild-type form.     

Evaluation of Tissue Dissociation of Durum Wheat Grain (Triticum durum Desf.) Generated by the Milling Process

The three major botanical components (starchy endosperm, aleurone layer and pericarp) of eight durum wheat samples exhibited significantly different compositions and concentrations in phenolic acids. The starchy endosperm, the aleurone layer and the pericarp were respectively characterised by a low content in ferulic acid (FA), a high content intrans -sinapic acid (t -SA), and a high content in ferulic acid dehydrodimers (DHD). These three chemical markers can be exploited to differentiate the three grain botanical parts within milling fractions and to evaluate the milling efficiency, particularly the separation between bran and endosperm. The histological dissociation of the wheat grain generated by the milling process can be investigated further into details using the three phenolic acids markers. A separability index (S i) was proposed in order to quantify the ease of dissociation of endosperm from bran. Differences in S i values between wheat varieties grown under various agricultural conditions demonstrated the relevant variability of this character. The structural and molecular factors implied in the control of tissue dissociation are discussed in details.     

Changes in Phenolic Compounds in Garlic (<Emphasis Type="Italic">Allium sativum</Emphasis> L.) Owing to the Cultivar and Location of Growth

The contents of total phenolic compounds, flavonoids, and phenolic acids were determined in selected garlic cultivars grown at four locations. The total phenolic content varied from 3.4 mg gallic acid equivalents (GAE)/g of dry matter (dm) to 10.8 mg GAE/g of dm with a mean value of 6.5 mg GAE/g of dm. The myricetin, quercetin, kaempferol, and apigenin flavonoids were not detected in any of the samples. Caffeic acid and ferulic acid were the major phenolic acids found with mean values of 2.9 mg/kg of dm and 2.6 mg/kg of dm, respectively. The mean contents of vanillic, p-hydroxybenzoic, and p-coumaric acids were comparable (0.4–0.8 mg/kg of dm), and the level of sinapic acid was negligible (< 0.1 mg/kg of dm). There was a significant effect of location but an insignificant effect of genotype on contents of caffeic, vanillic, p-hydroxybenzoic, and p-coumaric acids. However, genotype but not location affected the contents of total phenolics and ferulic acid. On average, the white garlic cultivars and Chinese garlic cultivars contained higher contents of total phenolics and ferulic acid than the purple garlic cultivars. However, the differences in the total phenolic content between the purple and white garlic cultivars were not significant.     

宁夏春小麦种质资源Wx基因分子鉴定及其分布

为明确宁夏春小麦种质资源Waxy基因的分布情况,利用Wx-A1、Wx-B1和Wx-D1位点的6个STS标记(PA1、PA2、PB1、PB2、PD1、PD2),对299个宁夏春小麦种质资源进行等位变异检测.结果 表明,供试小麦种质的Waxy基因组成以野生型(Wx-A1a/Wx-B1a/Wx-D1a)为主,占参试材料总数的...     

Phenolic acids composition,total polyphenols content and antioxidant activity of Triticum monococcum, Triticum turgidum and Triticum aestivum: A two-years evaluation

Wheat is a good source of polyphenols, plant metabolytes with beneficial effects on human health. However, little information is available on phenolic acid composition and concentration in different Triticum species, as well as on possible environmental effects. To shed some light on this issue, thirty-nine wheat accessions cropped for two years and belonging to different Triticum species (Triticum monococcum, Triticum turgidum ssp. dicoccum, turanicum and durum, Triticum aestivum ssp. spelta and aestivum) were assessed for phenolic acids (ferulic, p-coumaric, vanillic, syringic, p-hydroxybenzoic, caffeic acids and syringaldehyde), total polyphenols and antioxidant activity in soluble conjugated and insoluble bound extracts. Ferulic acid was the most abundant compound in both extracts. Insoluble bound phenolic acids represented >90% of total phenolic acids. Einkorn showed the maximum concentration of conjugated phenolic acids (50.5 mg/kg DM), while durum and bread wheats presented the highest content of bound phenolic acids (651.8 and 629.2 mg/kg DM, respectively). Cropping year influenced the concentration of conjugated but not of bound phenolic acids. A survey of phenolic acid distribution in the kernel showed that they are rare in endosperm, but abundant in germ and bran. Total polyphenols and antioxidant activity were highly correlated to phenolic acid content.     

新疆小麦品种春化和光周期主要基因的组成分析

为了明确新疆冬春麦区小麦春化和光周期基因的分布特点,利用STS标记对185份品种(系)的重要春化基因Vrn-A1、Vrn-B1、Vrn-D1、Vrn-B3和光周期基因Ppd-D1位点的等位变异组成进行了检测和分析。结果表明,在新疆小麦品种中,春化和光周期基因位点显性等位变异分布频率不同。含有春化显性等位变异Vrn-A1的品种47个,占供试品种(系)的25.4%;Vrn-B1为43个,占23.3%;Vrn-D1为38个,占20.5%;Vrn-B3位点不存在显性等位变异。春化显性等位变异Vrn-A1、Vrn-B1和Vrn-D1在冬、春性小麦内的分布比例也不同。在春性小麦品种(系)中,显性等位变异Vrn-A1出现的频率较高(55.3%);其次为Vrn-B1,占50.6%;Vrn-D1占44.7%。在冬性小麦中,仅有显性等位变异Vrn-B1出现,占2.0%。在光周期基因Ppd-D1位点,80.0%的品种(系)携带光不敏感显性等位变异Ppd-D1a;其中在春性和冬性小麦品种(系)中,Ppd-D1a出现的频率分别为83.5%和77.0%。新疆小麦品种(系)中,存在11种春化和光周期基因显性等位变异组合。     

面条品质性状相关基因在四川小麦中的分布

为给面条小麦亲本材料的选择提供依据,利用多重PCR技术分析了Wx-B1和2个主效PPO位点的等位基因在104份四川主栽小麦和骨干亲本中的分布,并检测了59份新育成品系的淀粉糊化特性.结果表明,控制低PPO活性的等位基因PPO-2Ab和PPO-2Da的频率分别为42.3%和83.6%,Wx-B1蛋白缺失基因Wx-B1b的频率为26.9%,四川小麦淀粉特性整体表现较优良.Wx-B1缺失小麦在峰值粘度、稀懈值、最终粘度和反弹值方面与正常类型间差异显著.绵阳26 、川麦107、川麦43等是面条小麦育种的优良亲本.准确、实用、高效多重PCR技术适合于多位点控制的品质性状的标记辅助选择.     

Isolation and characterization of a novel variant of HMW glutenin subunit gene from the St genome of Pseudoroegneria stipifolia

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.     

The antioxidant potential of milling fractions from breadwheat and durum

The effect of primary processing, namely milling, on the phenolic content and antioxidant capacity of two wheat cultivars, namely Canada Western Amber Durum (Triticum turgidum L. var. durum) and Canada Western Red Spring (Triticum aestivum L.) was studied. The milling products: bran, flour, shorts and feed flour fractions were examined. In addition, semolina was an end-product of durum wheat milling. Antioxidant activity of wheat phenoliocs was evaluated using oxygen radical absorbance capacity, inhibition of photochemiluminescence, the Rancimat method, and inhibition of oxidation of low-density lipoprotein cholesterol and deoxyribonucleic acid. The phenolic composition of wheat extracts was determined using high performance liquid chromatography. Bran showed the highest antioxidant activity whereas the endosperm possessed the lowest in both cultivars examined. The phenolic compounds are concentrated in the outermost layers namely the bran. The consumption of wheat with bran in the form of whole grain may provide beneficial health effects.     

Effects of different prolamin alleles on durum wheat quality properties

The F₄ progenies of four durum wheat crosses were used to determine the effects of different prolamin alleles on quality properties evaluated by the SDS sedimentation, mixograph, micro-alveograph and vitreousness tests and by protein content. Allelic compositions of the gliadins (Gli-B1 and Gli-2 loci) and the glutenins (Glu-1, Glu-3 and Glu-B2 loci) were determined. Alleles at the Glu-B3 locus showed a strong influence on quality measured by SDSS, mixograph and alveograph tests. Significant interactions between Glu-B3 and other glutenin loci were also detected. Prolamin composition explained more than 30% of the variation in SDSS, mixograph MT and alveograph W. The mixograph parameter BDR, and alveograph P and L parameters were the most erratic with between 8 and 76% of variation explained by prolamin composition. In general, no significant associations of prolamins with vitreousness or protein content were found. A significant correlation was detected between SDSS, MT and W. These results together with those from previous studies have important implications for wheat breeders since selection based on good alleles at Glu-B3 (a, c, j) together with favourable alleles at other loci such as Glu-A1 (subunit 1), Glu-A3 (a, c, d, h), Glu-B2 (a,b) and Gli-B1 (ω-35) could improve durum wheat quality.