一粒小麦种质遗传多样性分析

为了从野生一粒小麦中发掘有用基因,随机选取33个普通小麦EST-SSR标记和定位于小麦A基因组的41个普通小麦基因组DNA-SSR标记,对35份一粒小麦、3份四倍体小麦和1份普通小麦进行了遗传多样性分析。结果表明,在扩增这些标记位点的引物中有45对在一粒小麦上有扩增产物,其中33对检测出位点多态性,而且基因组DNA-SSR标记的多态检测率明显高于EST-SSR标记多态检测率。这些多态位点包括211个等位位点,平均每个位点有6.03个等位变异。利用PHYLIP分析软件按UPGMA方法对这些一粒小麦种质进行了聚类分析,以遗传距离0.5为界,可以将其分为7种类型。这种聚类关系与对应种质的白粉病抗性呈现出一定的相关性,因此根据聚类结果可以在一定程度上推测相关种质所携带的抗白粉病基因的起源和变异。对一粒小麦与野生二粒小麦种质的遗传距离的分析结果表明,不同来源的二粒小麦的A基因组可能有不同的起源。     

三粒小麦与甘麦8号亲缘关系的SSR标记分析

三粒小麦每朵小花通常可以结三粒种子。三粒小麦被认为是普通小麦"甘麦8号"的自然突变体,但一直缺乏分子证据。为了探讨三粒小麦与甘麦8号的亲缘关系,本研究利用SSR标记对三粒小麦、甘麦8号及其姊妹系等16份小麦材料进行了遗传多样性分析,63对引物共扩增出275条多态性带;遗传相似性分析表明,三粒小麦与甘麦8号之间未表现出更近的遗传距离;聚类分析将三粒小麦单独聚在一个亚组,而甘麦8号、甘麦8号的姊妹系及其亲本聚在另一个亚组,说明三粒小麦不一定来源于甘麦8号的自然突变。     

乌拉尔图和栽培一粒小麦抗病基因向普通小麦转移的研究

乌拉尔图小麦（Triticum urartu Tum．）和栽培一粒小麦（Triticum monococcum L．）是普通小麦的两个二倍体野生种，是进行小麦遗传改良的重要遗传资源。为了将其抗白粉病和抗条锈病基因转移到普通小麦中，用普通小麦分别与两份乌拉尔图小麦材料1010013和1010015及一份栽培一粒小麦材料1010048配制杂交组合。结果表明，乌拉尔图小麦与普通小麦杂交不能正常结实，必须进行幼胚拯救。成胚率为14．77％；而栽培一粒小麦与普通小麦杂交可正常结实，但结实率很低。杂种F1自交不育，与普通小麦回交可正常结实．但BC1自交结实率极低。对普通小麦与乌拉尔图小麦杂种F1花粉母细胞减数分裂中期Ⅰ的观察结果表明，平均单价体为17．36个．二价体为5．32个。进一步对杂种后代进行抗病鉴定和遗传分析，乌拉尔图小麦1010013和1010015分别含有一对显性抗白粉病基因。栽培一粒小麦1010048含有两对独立遗传的显性抗条锈病基因，并分别在杂种后代BC2F1和BC1F2中获得了染色体正常（2n=42）、细胞学稳定且抗性与供体亲本一致的抗白粉病和抗备锈病植株。说明来自二倍体乌拉尔图和栽培一粒小麦的抗病基因已通过遗传重组导入到普通小麦中。研究还发现普通小麦莱州953与乌拉尔图小麦和栽培一粒小麦杂交的结实率与中国春的同样高，表明其可能携带有远缘杂交亲和基因。     

硬粒小麦与玉米杂交力的变异

为了检测硬粒小麦与玉米杂交力的变异情况,将两套硬粒小麦材料和硬粒小麦品种Ｌａｎｇ－ｄｏｎ的一套Ｄ组染色体代换系与玉米杂交,然后将分蘖分开,进行液体培养,并进行２,４－Ｄ或硝酸银处理（即给分蘖培养液中加入２,４－Ｄ或硝酸银）。结果表明,硝酸银使２５个硬粒小麦育种系×玉米的胚形成百分率由１．４％提高到了２．８％。在３２个硬粒小麦材料（高代品系和品种）与玉米的杂交中,加入硝酸银后的胚形成频率为０～１５．８％;其中有７个基因型的胚形成频率高于６．０％,这与它们的系谱有关。一套染色体代换系与玉米杂交后,其胚形成频率为０．４％～５８．１％,其中具有１Ｄ、３Ｄ、４Ｄ和７Ｄ染色体代换系的胚形成频率较高。这些结果表明：①给２,４－Ｄ处理液中加入硝酸银可以提高平均胚形成频率,但总体看来对硬粒小麦种子和胚的发育无明显效应;②将有些Ｄ组染色体转入硬粒小麦遗传背景后能够提高其杂交力。     

野生一粒小麦根干旱响应蛋白的筛选与鉴定

为解析野生一粒小麦根响应干旱胁迫的调控网络,用20%(w/v)PEG6000处理两叶一心期野生一粒小麦,通过对小麦根蛋白质的分离和鉴定,分析了干旱胁迫下野生一粒小麦根中的蛋白质变化。结果共分离、鉴定得到85个表达差异倍数在1.5以上的蛋白质。这些差异蛋白主要涉及碳代谢(27%)、氨基酸代谢(15%)、解毒与防御(11%)、分子伴侣(8%)、能量代谢(8%)、信号传导(6%)、蛋白质代谢(5%)、脂代谢(4%)、转录与翻译(4%)、核苷酸代谢(2%)以及骨架蛋白(1%)。对这些表达差异蛋白进行进一步的功能分析,发现大部分信号传导相关蛋白上调表达;碳代谢途径中的糖酵解相关蛋白下调表达,而磷酸戊糖途径相关蛋白上调表达。同时下调表达的还包括蛋白质代谢相关蛋白。大部分氨基酸代谢相关蛋白质下调表达,但是谷氨酸脱羧酶及甲硫氨酸合酶含量上升。结果表明,干旱胁迫增强了野生一粒小麦根中信号传导与磷酸戊糖途径代谢,促进了谷氨酸与甲硫氨酸的生物合成,降低了糖酵解与蛋白质代谢等过程。研究结果丰富了野生一粒小麦根响应干旱胁迫机制信息。     

矮秆大穗多粒小麦亲本百泉3380和郑州86115产量性状配合力分析

矮秆大穗多粒小麦亲本百泉３３８０和郑州８６１１５与６个小麦品种（系）组成双列杂交。配合力分析表明，百泉３３８０和郑州８６１１５的矮秆性和多粒性的一般配合力高，宜作为小麦高产，超高产杂交育种中的矮杆大穗多粒亲本使用。     

灌浆前期高温对小麦籽粒氮代谢关键酶活性的影响

为探讨花后高温胁迫对小麦籽粒氮代谢及蛋白质合成的影响机制,以黄淮地区高产小麦品种郑麦366为材料,利用人工气候室模拟花后高温的方式,在盆栽条件下研究了灌浆前期短暂高温对小麦强势粒和弱势粒谷丙转氨酶(GPT)、谷草转氨酶(GOT)活性的影响.结果表明,灌浆前期高温显著提高了籽粒蛋白质含量,降低了籽粒蛋白质积累量和氮代谢关键酶GPT、GOT活性,其中强势粒GPT活性受高温胁迫的影响较大.小麦籽粒蛋白质含量与GPT和GOT活性均呈负相关,但相关性在不同时期间、强势粒与弱势粒间有差异,强势粒GPT活性与蛋白质含量的关系更密切.     

野生二粒小麦叶绿体基因RNA编辑位点的预测、鉴定与分析

RNA编辑是高等植物叶绿体基因转录后表达调控的一种重要方式。为了解野生二粒小麦叶绿体基因RNA编辑的组成及其与其他麦类作物的异同,通过生物信息学预测结合RT-PCR的方法,对野生二粒小麦叶绿体基因的RNA编辑位点进行了预测和鉴定。生物信息学预测共发现了分布于15个基因上的35个编辑位点,均为C到U的转换,其中ndhB基因包含的编辑位点数量最多,达9个;在此基础上,随机选取5个基因对其编辑位点进行了测序验证,结果共鉴定了18个C→U的编辑位点;进一步对编辑后编码蛋白的二级结构和跨膜结构域进行了预测,发现编辑后所有基因均发生了二级结构的改变,但只有ndhB基因的跨膜结构域发生了改变;最后,将确定的野生二粒小麦叶绿体基因RNA编辑位点与7个禾本科物种的RNA编辑位点进行比较,共发现17个编辑位点在这些种间具有保守性,相比于其他物种,野生二粒小麦与普通小麦和粗山羊草具有更相似的编辑位点组成。     

我国小麦穗粒数及多粒种质的研究进展

本文对我国小麦品种穗粒数的分布、变化和近年多粒种质资源研究的进展进行了总结。我国小麦穗粒数平均为３２．５粒，７０％的品种在２５－４０粒之间。穗粒数呈现明显的地区性分布。总的趋势是南多北少，东低西高。不同时期穗粒水平不一样，８０年代全国穗粒数平均为３６．３粒，较５０年代增加了约６粒，增长了１９％。多粒品种的系谱分析表明：多粒源有国内品种、国外引进品种和小麦近缘种属材料等，其中国外品种比例较大。阿勃、     

我国小麦穗粒数及多粒种质的研究进展

本文对我国小麦品种穗粒数的分布、变化和近年来多粒种质资源研究的进展进行了总结。我国小麦穗粒数平均为３２．５粒，７０％的品种在２５－４０粒之间。穗粒数呈现明显的地区性分布。总的趋势是南多北少，东低西高。不同时期穗粒水平不一样，８０年代全国穗粒数平均为３６．３粒，较５０年代增加了约６粒，增长了１９％。多粒品种的系谱分析表明：多粒源有国内品种、国外引进品种和小麦近缘种属材料等，其中国外品种比例较大。阿勃、阿夫、欧柔、亥恩·亥德和郑引ｌ号等我国著名的矮源、大粒源、抗病源也是重要的多粒源。本文从我国小麦品种穗粒数的特点出发，提出了多粒育种宜在现有水平上增加３－４粒的穗粒指标及今后多粒种质鉴定、创新的重点。     

Tocols and carotenoids of einkorn,emmer and spring wheat varieties: Selection for breeding and production

Einkorn (Triticum monococcum L., subsp. monococcum), emmer (Triticum dicoccum Schuebl [Schrank], subsp. dicoccum) and spring bread wheat (Triticum aestivum L.) may be rich in lipophilic antioxidants (tocols and carotenoids), and therefore potential food sources with good nutritional properties. The aim of the present study was to determine the contents of major lipophilic antioxidants beneficial for human health in wheat varieties and landraces for breeding and production. In field experiments over two years, fifteen einkorn, emmer and spring wheat varieties were analysed for the contents of tocols and carotenoids in grain. A high carotenoid content (lutein, zeaxanthin, β-carotene) was typical for the selected einkorn genotypes. Among the analysed wheat species, the highest content was of β-tocotrienol, especially in the einkorn accessions. α-Tocotrienol was abundant in einkorn and emmer wheat species. Higher contents of α- and β-tocopherols were characteristic of spring and emmer wheats. δ-Tocotrienol has been detected for the first time in einkorn and some emmer accessions, although in low concentrations. Significant effects of genotype on the contents of carotenoids and tocols were found with einkorn differing from emmer and spring wheats. The year of cultivation had less effect on the contents of carotenoids and tocols. Selected accessions of einkorn with high contents of carotenoids and tocotrienols as well as spring and emmer wheats with higher contents of tocopherols are good sources of antioxidants with potential health promoting benefits for the production of nutritionally enhanced foods.     

Low molecular phytochemicals of Indian dwarf (Triticum sphaerococcum Percival) and Persian wheat (T. carthlicum Nevski) grain

Ancient wheat grain is considered by consumers to be more natural, pro-healthy and better tolerated, so these genotypes are being steadily reintroduced to cultivation. This study presents the content and composition of phenolic acids, alkylresorcinols, sterols, tocols and carotenoids in the grain of Indian dwarf and Persian wheats, extended by characteristics of their kernels (weight, dimensions and colour). To compare these features, four other wheat species (bread, spelt, durum and einkorn wheats) were used. It was found that the grain of Indian dwarf and Persian wheat is similar in weight and dimensions to grain of einkorn wheat, while in colour to bread wheat. Among the tested samples, grain of both new genotypes was the richest source of total low molecular phytochemicals, especially phenolic acids and alkylresorcinols, while being the weakest source of carotenoids. For these wheats, an enhanced share of ferulic acid (93–95%) was found, accompanied by higher quantitative and qualitative variability of homologues within sterols, tocols and carotenoids. In turn, the alkylresorcinol composition was related to wheat ploidy level.     

Evaluation of heat damage, sugars, amylases and colour in breads from einkorn, durum and bread wheat flours

To limit nutritional losses and optimise bread processing, heat damage indices (furosine, glucosylisomaltol, hydroxymethylfurfural), sugars, α-amylase, β-amylase and colour were monitored during bread manufacturing from refined flour of three einkorn, three bread and one durum wheat samples. The heat damage indices increased only during the baking step. Furosine was significantly lower in einkorn (on average, 9.3 ± 5.33 and 25.3 ± 10.70 mg/100 g protein in crumb and crust, respectively) than in bread wheat (31.6 ± 3.05 and 115.6 ± 13.53) and durum wheat (36.2 ± 2.82 and 165.0 ± 3.17). Glucosylisomaltol and hydroxymethylfurfural were detected only in the crust, with lower levels in einkorn (on average, 2.3 ± 1.78 and 10.0 ± 7.79 mg/kg DM, respectively) than in bread wheat (13.1 ± 5.57 and 42.8 ± 10.64) and durum wheat (18.9 ± 1.11 and 57.2 ± 0.80). The different behaviour of einkorn was probably related to its moderate β-amylase activity, and thus the low maltose content of its dough. Colour was correlated with heat damage, as einkorn breads were lighter than the others.The results show that einkorn bread undergoes lower heat damage than analogous products from durum and bread wheat, thus probably better preserving its nutritional value.     

Alkylresorcinol composition allows the differentiation of Triticum spp. having different degrees of ploidy

Total alkylresorcinol (AR) content and homologue composition were assessed in whole grain flours of 15 varieties each of bread wheat, durum, spelt, emmer, and einkorn grown in four different environments. Bread wheat (761 ± 92 μg/g DM) and spelt (743 ± 57 μg/g) belonging to the hexaploid species showed higher AR concentrations than the tetraploid durum (654 ± 48 μg/g, p < 0.05), while the concentrations found in the diploid einkorn (737 ± 91 μg/g) and the tetraploid emmer (697 ± 94 μg/g) did not significantly differ from the other species. The AR content showed a remarkable heritability and, thus, seemed to be mainly determined by genetic factors. If ARs were assumed to be deposited within a specific AR-rich layer of the kernel, AR levels of all varieties would easily surpass their minimal inhibitory concentrations against fungal pathogens within this barrier layer. Although the AR carrying a C21:0 side chain was the main homologue in all species, the levels of all AR homologues and their relative composition significantly differed between hexaploid (bread wheat and spelt), tetraploid (durum and emmer) and diploid (einkorn) species. Consequently, a clear-cut differentiation of Triticum species and derived whole grain flours according to their degrees of ploidy was established based on concentrations of saturated C₁₇-, C₁₉-, C₂₁-, C₂₃-, and C₂₅-substituted ARs.     

Evidence for different supramolecular arrangements in pasta from durum wheat (Triticum durum) and einkorn (Triticum monococcum) flours

The effects of the replacement of einkorn flour on pasta proteins aggregation were studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis and size exclusion high performance chromatography. Pasta was produced replacing durum wheat semolina with an increasing amount of einkorn flour (30, 50 and 100%). The polymeric protein structure of flours and related pasta and pasta mixture was determined by protein subunits composition and size of polymeric proteins. The unextractability of polymeric protein was related to the unextractable protein fraction and to the determination of –SH/-SS groups. Durum wheat semolina and einkorn flours increased their unextractable and polymeric fractions during pasta processing. The unexpected results derived from the areas of unextractable fractions and total and large unextractable polymeric fractions of 70/30 semolina/einkorn pasta mixture that were lower than those of 50/50 semolina/einkorn pasta mixture. Although the semolina flour contained more gluten proteins than einkorn flour, a higher aggregation was registered for 50/50 semolina/einkorn flour pasta. These results suggested that a different assessment of gluten network occurred in pasta mixture and it was regulated by a self-assembling machine influenced by nature of HMW-GS. The 50/50 semolina/einkorn pasta mixture determined a supramolecular structure in the developing of its network architecture.     

Effects of species and breeding on wheat protein composition

Wheat proteins are characterized by their excellent contribution to technological and baking properties. However, wheat proteins, especially gluten and amylase-trypsin inhibitors (ATIs), are also known to be responsible for a broad range of intolerances and allergies. In order to evaluate the impact of genetic variability on the composition of these functional but immunogenic protein types, a set of different Triticum species, including common wheat, durum, spelt, emmer and einkorn, was examined regarding ATI and gluten concentrations by RP-HPLC. Additionally, inhibition towards trypsin was determined by an enzymatic assay. Based on the results, none of the investigated wheat species can be considered to be less ‘immunogenic’. Nevertheless, due to the large variability of ATI and gluten amounts among different genotypes, the selection of less-immunoreactive wheat varieties for individuals that suffer from wheat related diseases (WRDs) might be possible. The impact of breeding was assessed for different varieties of common wheat from different breeding periods. Results revealed significant improvement of technologically valuable parameters such as the amount of high molecular weight (HMW) glutenins and the gliadin to glutenin ratio, but no increase in immunogenic proteins.     

Nitrogen fertilisation effects on technological parameters and carotenoid,tocol and phenolic acid content of einkorn (Triticum monococcum L. subsp. monococcum): A two-year evaluation

Recent studies on einkorn wheat, an underutilised relative of durum and bread wheat, demonstrated its outstanding nutritional characteristics and fostered a renewed interest for its cultivation. Einkorn is a disease-resistant and thrifty crop, supplying flour with optimal composition even with minimal agronomic management. To understand the role of nitrogen fertilisation on its composition and nutritional quality, a two-year study comparing five different nitrogen treatments (0 kg/ha, 40 and 80 kg/ha at tillering, 40 and 80 kg/ha at heading) was performed on three einkorn accessions.The two years had similar temperatures but very different rainfall profiles, so the climate had a strong effect on most traits, including thousand kernels weight, Falling number, viscoamylographic parameters, carotenoid and phenolic acid concentration. On the other hand, nitrogen fertilisation improved protein content, SDS sedimentation volume and phenolic acids concentration. Carotenoids synthesis was slightly limited with increasing fertilisation; a similar, but less evident, effect was present for tocols. The results demonstrate that einkorn wheat does not require abundant nitrogen fertilisation to provide flour with good nutritional and technological characteristics.     

Storage-induced changes in einkorn (Triticum monococcum L.) and breadwheat (Triticum aestivum L. ssp. aestivum) flours

To assess the effect of ageing on alpha-amylase activity, falling number, pasting properties and SDS sedimentation volume, whole meal and white flours of einkorn (cv Monlis) and bread wheat (cv Serio) were stored in darkness at different temperatures and analysed several times up to 374 days. Pregerminated bread wheat flours (cv Blasco) were also evaluated.     

Does wheat make us fat and sick?

After earlier debates on the role of fat, high fructose corn syrup, and added sugar in the aetiology of obesity, it has recently been suggested that wheat consumption is involved. Suggestions have been made that wheat consumption has adverse effects on health by mechanisms related to addiction and overeating. We discuss these arguments and conclude that they cannot be substantiated. Moreover, we conclude that assigning the cause of obesity to one specific type of food or food component, rather than overconsumption and inactive lifestyle in general, is not correct. In fact, foods containing whole-wheat, which have been prepared in customary ways (such as baked or extruded), and eaten in recommended amounts, have been associated with significant reductions in risks for type 2 diabetes, heart disease, and a more favourable long term weight management. Nevertheless, individuals that have a genetic predisposition for developing celiac disease, or who are sensitive or allergic to wheat proteins, will benefit from avoiding wheat and other cereals that contain proteins related to gluten, including primitive wheat species (einkorn, emmer, spelt) and varieties, rye and barley. It is therefore important for these individuals that the food industry should develop a much wider spectrum of foods, based on crops that do not contain proteins related to gluten, such as teff, amaranth, oat, quinoa, and chia. Based on the available evidence, we conclude that whole-wheat consumption cannot be linked to increased prevalence of obesity in the general population.