小麦面粉黄色素相关基因研究

小麦八氢番茄红素合成酶(PSY)基因和脂肪氧化酶(LOx)基因可能影响面粉黄色素含量。根据玉米P5y 基因序列设计引物,扩增出小麦PSY基因的部分片段,序列比较表明小麦和玉米PSY基因外显子DNA序列长度一致,但存在单核苷酸多态性(SNP)位点,序列一致性为90％;蛋白质氨基酸序列比较发现其序列一致性为97％, 说明一些SNP并未导致氨基酸的改变,该基因在玉米和小麦中应具有类似的功能活性。利用非整倍体材料将小麦 PSY基因初步定位到1D染色体。用同样方法,发现小麦的LOX基因与大麦、水稻、玉米的L0X基因具有很高的一致性,并将其初步定位到4BS染色体。     

癌基因PPO及其同源性基因的结构分析

目的 采用PPO（proliferation and phosphorylation oncogene）基因与其同源性基因的结构分析,推测PPO并验证其功能。方法 利用PPO的蛋白序列寻找同源基因,比较其结构并利用蛋白免疫杂交方法证实其功能。结果 克隆了PPO基因,找到了PPO基因与小鼠、果蝇、蚊子、线虫以及酵母等的同源基因,比较发现PPO在进化上非常保守。人和小鼠的氨基酸序列有许多与磷酸化有关的功能域,并发现其中某些氨基酸在进化上非常保守。进一步研究表明PPO能使ERK2和MEK磷酸化。结论 PPO基因在进化上非常保守,与磷酸化功能有关。     

小麦tae-MIR156前体基因的克隆及其靶基因TaSPL17多态性分析

Squamosa-promoter binding protein (SBP)-box基因是植物特有的一类转录因子, 广泛参与植物生长发育, 其部分成员受miR156调控。文章克隆了小麦(Triticum aestivum) tae-MIR156前体基因, 转录后能够形成茎环结构。小麦10个SBP-box基因中, 仅TaSPL3和TaSPL17在编码区存在tae-miR156识别位点。SPL17在普通小麦的A基因组供体种乌拉尔图小麦(Triticum urartu, AA) UR209和B基因组供体种拟斯卑尔脱山羊草(Aegilops speltoides, BB) Y2001中均为多拷贝(SPL17-A1、SPL17-A2和SPL17-A3; SPL17-B1、SPL17-B2和SPL17-B3), 在D基因组供体种粗山羊草(Aegilops tauschii, DD) Ae38中仅检测到一种序列(SPL17-D); SPL17-A2与SPL17-B2, SPL17-A3与SPL17-B3、SPL17-D两两之间序列的一致性程度均大于99%, 且与普通小麦(中国春、衡观35和双丰收)的TaSPL17序列具有较高的一致性, 提示它们可能来源于共同的祖先基因, 并且在进化过程中高度保守。靶基因TaSPL17中的tae-miR156识别位点非常保守, 在根据单株穗数和基因型多样性挑选的SubP1和SubP2群体中均未检测到tae-miR156识别位点存在变异碱基。     

小麦PPO活性基因等位变异的区域分布研究

为了解中国不同生态区小麦种质资源籽粒多酚氧化酶(PPO)活性基因的等位变异的差异与分布,利用小麦PPO活性基因的功能标记PPO16、PPO29与PPO18,检测了来自中国7个不同生态麦区的379份小麦种质资源的等位变异和分布差异。结果表明:(1)在2AL染色体该基因位点有2种等位变异类型:Ppo-A1a(高PPO)和Ppo-A1b(低PPO),其频率分别为51.5%和48.5%。(2)在2DL染色体该基因位点有3种等位变异类型:Ppo-D1a(低PPO)、Ppo-D1b(高PPO)和Ppo-D1ab(中间型),其频率分别为57.8%、32.5%和9.8%。(3)该基因在2AL和2DL染色体上的位点变异有6种不同类型的组合:Ppo-A1a/D1a(中间型)、Ppo-A1a/D1b(高PPO)、Ppo-A1a/Ppo-D1ab(中间型)、Ppo-A1b/D1a(低PPO)、Ppo-A1b/D1b(中间型)和Ppo-A1b/Ppo-D1ab(中间型),其中,与低PPO活性相关的基因型组合Ppo-A1b/D1a的频率为25.6%。(4)小麦PPO活性基因不同变异类型在各生态区的分布存在明显差异,基因型Ppo-A1b在北部冬麦区和西南冬麦区的比例较大,基因型Ppo-D1a在黄淮冬麦区和北部冬麦区的比例较大,基因型组合Ppo-A1b/D1a在北部冬麦区的比例较大。研究认为,结合采用分子标记辅助选择(MAS),有利于小麦籽粒外观品质的遗传改良和新品种选育。     

小麦淀粉粒束缚淀粉合成酶基因多态性的分子鉴定

运用6％的SDS-PAGE对14个小麦品种成熟籽粒Wx蛋白的多态性进行了鉴定,结果表明,14个小麦品种根据其Wx蛋白的缺失情况可分为6种组合类型。另外,根据Wx-A1、Wx-D1和Wx-D1这3个位点基因序列和变异情况分别设计了PCR引物,扩增结果表明：Wx-A1位点突变材料扩增产物为327bp,正常材料中扩增不到该特异带;在Wx-B1位点扩增出187bp目标带,突变材料没有该扩增产物;在Wx-D1位点扩增出约700bp目标带,突变材料没有该特异带。与前人的研究结果相比,Wx-B1引物在3个位点的扩增产物长度更短,差异更大,在2％琼脂糖胶上即可清楚分开,缩短了鉴定时间,提高了效率,为大规模筛选优质面条小麦品种提供了可能。     

黄淮麦区小麦子粒多酚氧化酶活性基因等位变异的分子检测

摘要: 籽粒多酚氧化酶（Polyphenol oxidase,PPO）活性是造成面粉以及面制品褐变的主要因素,了解不同小麦品种籽粒PPO活性基因的等位变异情况,有助于遗传改良中提高面制品的外观品质。本研究利用2A染色体上Ppo-A1的标记PPO18以及2D染色体上Ppo-D1的标记PPO16和PPO29检测该基因在118份黄淮麦区小麦品种中的等位变异。结果表明：在Ppo-A1位点,48.3％的小麦品种含Ppo-A1a（高PPO活性）型等位基因,51.7％的小麦品种含Ppo-A1b（低PPO活性）型等位基因,Ppo-A1a和Ppo-A1b两者之间的差异达到显著水平（P﹤0.05）。在Ppo-D1位点,55.1％的小麦品种含Ppo-D1a（低PPO活性）型等位基因,44.9％的小麦品种含Ppo-D1b（高PPO活性）型等位基因,Ppo-D1a和Ppo-D1b两者之间的差异也达到显著水平（P﹤0.05）。在Ppo-A1和Ppo-D1两个位点共检测到Ppo-A1a/Ppo-D1a（中间型PPO活性)、Ppo-A1a/Ppo-D1b（高PPO活性）、Ppo-A1b/Ppo-D1a（低PPO活性）、Ppo-A1b/Ppo-D1b（中间型PPO活性）四种变异组合类型,分布频率分别为28.8％、19.5％、26.3％和25.4％,彼此之间的差异均达到显著水平（P﹤0.05）。总体来看,这三个基因特异性标记可以快速、准确和方便的检测籽粒PPO基因的不同等位变异。此外,本研究检测出部分材料具有低PPO活性,可为选育具有低PPO活性的小麦品种提供有用信息。     

酒精依赖相关基因的遗传多态性

酒精依赖综合征受到复杂的生理、心理、个体遗传及环境等诸多因素的影响。有关研究已经证实了某些候选基因和酒精依赖密切相关。文章主要对与酒精依赖相关的酒精代谢关键酶(乙醇脱氢酶和乙醛脱氢酶以及细胞色素P450 2E1)基因以及调节神经递质作用的酶和受体(儿茶酚氧位甲基转移酶, 多巴胺受体D2、D4, μ阿片受体)基因遗传多态性研究作一综述。     

山东保存小麦种质资源面粉白度分析

对2068份小麦种质资源进行了面粉白度测定和高白度小麦种质子粒硬度测定。结果表明,山东小麦地方品种、山东小麦育成品种和省外引进小麦品种面粉白度值的分布范围分别为63.9～82.9、63.1～83.8和67.2～84.2。筛选出面粉白度值大于80的小麦种质342份(包括白度值大于83的种质26份),其中地方品种22份,山东育成品种(系)228份,省外引进种质92份。从高白度小麦种质资源中,筛选出子粒硬度指数≥50符合高白度强筋、中强筋或中筋的种质资源18份,对培育中筋以上高白度小麦新品种,以满足人们口味和健康保障具有重要意义。     

小麦钙网蛋白基因TaCRT-A多态性及其定位

以苗期抗旱性不同的37份六倍体普通小麦(AABBDD)、3份A基因组材料(AA)和3份四倍体小麦(AABB)为材料,通过直接测序法检测TaCRT-A基因的单核苷酸多态性,分析该基因多态性与小麦苗期抗旱性的关系,并进行遗传定位.结果表明:TaCRT-A基因DNA长度为3887 bp,在总长度为167141 bp的核苷酸序列中共检测到202个核苷酸变异位点,其中包括165个SNP和37个InDel,二者出现的频率分别为1/1013 bp和1/4517 bp.编码区的核苷酸多样性π值小于非编码区,编码区所承受的选择压力较大.43份试材可分为14种单倍型,其中H1、H2和H13分别含有普通小麦二倍体野生近缘种A基因组供体种的1份材料,H6、H7分别包含抗旱性极强的1份材料,H8包含四倍体波斯小麦并同时包含抗旱材料与干旱敏感材料,H11主要包括强抗旱材料与中等抗旱材料;虽然TaCRT受水分胁迫诱导表达,但TaCRT-A基因的结构多态性分析未能揭示其多态性与小麦苗期抗旱性之间的直接关系;利用RIL群体(Opata 85 ×W7984)将该基因定位于3A染色体标记Xmwg30～Xmwg570之间,遗传距离分别为10.5 cM和49.6 cM.     

小麦面粉RVA粘度特性的遗传潜势和聚类分析

分析了84个小麦品种(系)面粉的RVA特征参数,结果表明:7个RVA粘度性状在不同品种(系)间存在极显著的差异;所有RVA特征值具有较高的广义遗传力;根据全部7个RVA特征参数和仅用高峰粘度、低谷粘度和最终粘度3个指标将84个品种(系)聚类的结果几乎完全相同,结果是不同品种(系)总体上有按不同生态型聚集的趋势,变异系数的大小决定着聚类的结果.南方品种(系)绝大部分聚为一类,这类品种的RVA特征值均较高,但各参数变异较小;绝大部分北方品种(系)和加拿大品种聚为一类,这类品种所有RVA特征值均较低,但变异系数均较大;其它品种(系)聚为一类,其RVA参数为3类中最低,变异系数却为最高,且最终粘度低于或接近高峰粘度.小麦面粉RVA粘度高低的总体表现是:第Ⅰ类(南方为主型)>第Ⅱ类(北方为主型)>第Ⅲ类(特殊型).     

Flavonoid compounds related to seed coat color of wheat

In red wheat, reddish-brown pigments accumulate in testa of mature seeds. Half-cut wheat seeds were immersed in p-dimethylaminocinnamaldehyde (DMACA) reagent that stains flavanol structures blue. Testa of 10–40 days after flowering (DAF) in red wheat (“Norin 61” and “Satonosora”) seeds were stained blue and the reagent color changed to blue with 10–25 DAF seeds. No blue staining was observed in white wheat (“Tamaizumi”) seeds during maturation. “Norin 61” seed coats at 10 DAF contained dihydroquercetin, dihydromyricetin, (+)-catechin, procyanidin B3, and prodelphinidin B3, which were identified by HPLC-diode array detector and LC-MS/MS analyses. These five components began accumulating 7 DAF, reached maxima at 10 or 15 DAF, and then decreased in red wheat seeds, but were not detected in white wheat seeds. These results suggest that flavanol and proanthocyanidins are possible precursors of the reddish-brown pigments of red wheat seeds, and are converted to insoluble compounds as the seeds mature.     

小麦抗白粉病基因

到目前为止,小麦中已经鉴定出31个主效抗白杨病基因位点(Pm1-Pm31),对这些小麦抗白粉病基因位点的来源、染色体定位、遗传特点以及载体品种等方面进行了概括性综述。     

Development of a STS marker linked to a major locus controlling flour colour in wheat (Triticum aestivum L.)

Flour colour is an important quality trait in the production of bread, noodles and other related end products. Current screening for flour colour in breeding programs requires several grams of flour to be milled. In order to screen large numbers of plants, a rapid PCR-based assay is required. We report here the conversion of a codominant AFLP marker linked to a major locus controlling flour colour in hexaploid wheat, to a sequence tagged site (STS) marker for use in marker-assisted selection (MAS). The two-allelic AFLP bands were cloned and sequenced to allow specific primers to be designed. The primers amplified bands of the expected size in the parental varieties and co-segregated with the original AFLP marker in the mapping population. The primers also amplified alleles of the expected size from the DNA of parental lines of two other related mapping populations. Cultivars that contributed to the pedigree of the original parent `Schomburgk' used to generate the mapping population were also screened to determine the origin of the `yellow' allele.     

Nutritional and technological behavior of stabilized iron-gluconate in wheat flour

Food fortification has been shown to be an effective strategy to overcome iron malnutrition. When a new iron compound is developed for this purpose, it must be evaluated from a nutritional and technological point of view before adding it into foods. In this way, we have evaluated ferrous gluconate stabilized by glycine as a new iron source to be used in wheat flour fortification. We performed biological studies in rats as well as sensory perceptions by human subjects in wheat flour fortified with this iron source. The productions of pentane as a rancidity indicator as well as the change of the sensorial properties of the biscuits made with stabilized ferrous gluconate-fortified wheat flour were negligible. Iron absorption in water from this iron source was similar to the reference standard ferrous sulfate. Nevertheless, because of the phytic acid content, iron absorption from fortified wheat flour decrease 40% for both iron sources. The addition of zinc from different sources did not modify iron absorption from ferrous sulfate and stabilized ferrous gluconate in water and wheat flour. The iron absorption mechanism as well as the biodistribution studies demonstrate that the biological behavior of this iron source does not differ significantly from the reference standard. These results demonstrate that the iron source under study has adequate properties to be used in wheat flour fortification. Nevertheless, more research is needed before considering this iron source for its massive use in food fortification.     

大豆种皮色相关基因研究进展

大豆种皮色在从野生大豆到栽培大豆的演变过程中逐渐从黑色变成黄色,是重要的形态标记,因此,大豆种皮色相关基因研究无论对进化理论还是育种实践都具有重要的意义。种皮颜色是通过各种花色苷的沉积而形成的。虽然很多植物色素沉积的分子调控机制比较明晰,但大豆中控制种皮颜色形成的基因尚未被完全了解。文章综述了控制大豆种皮色基因与位点的相关研究进展,主要有I、T、W1、R、O 5个经典遗传位点,其中I位点被定位在第8号染色体(A2连锁群)一个富含查尔酮合成酶(CHS)的区域,CHS基因在大豆中是多基因家族且同源性较高;定位于第6号染色体(C2连锁群)T位点的基因F3’H已被克隆和转基因验证,由于碱基缺失导致所编码的氨基酸缺少了保守域GGEK,从而不能与血红素结合而丧失功能;R位点定位在第9号染色体(K连锁群)A668-1与K387-1两标记之间,可能是R2R3类MYB转录因子,也可能是UDP类黄酮3-O糖基转移酶;O位点定位在第8号染色体(A2连锁群)Satt207与Satt493两标记之间,其分子特性尚不清楚;W1位点可能由F3’5’H基因控制遗传。     

Carbohydrate structural analysis of wheat flour arabinogalactan protein

The water-extractable arabinogalactan protein (AGP) was isolated from bread wheat flour (Triticum aestivum L. variety Cadenza) and the structure of the arabinogalactan (AG) carbohydrate component was studied. Oligosaccharides, released by hydrolysis of the AG with a range of AGP-specific enzymes, were characterised by Matrix Assisted Laser Desorption Ionisation (MALDI)-Time of Flight (ToF)-Mass Spectrometry (MS), MALDI-ToF/ToF high energy collision induced dissociation (CID) and Polysaccharide Analysis by Carbohydrate gel Electrophoresis (PACE). The AG is composed of a β-(1→3)-d-galactan backbone with β-(1→6)-d-galactan side chains. These side chains are highly variable in length, from one to at least 20 Gal residues and are highly substituted with α-l-Araf. Single GlcA residues are also present at the non-reducing termini of some short β-(1→6)-galactan side chains. In addition, the β-(1→6)-galactan side chains are also substituted with β-l-Arap. We propose a polysaccharide structure of the wheat flour AGP that is substantially revised from earlier models.     

Mineral supplementation of white wheat flour is necessary to maintain adequate mineral status and bone characteristics in rats

This experiment was designed to compare the effect of ingestion of a wheat flours on mineral status and bone characteristics in rats. White flour was tested either without further mineral supplementation or with Mg, Fe, Zn and Cu supplementation. The flour diets were compared to a control purified diet. Four groups of 10 male Wistar rats each were fed one of the experimental diets for 6 wk and mineral status and tissue retention as well as bone characteristics were determined. As expected, mineral intake, except for calcium, was significantly lesser in rats fed the white flour diet than in the other groups. The rats fed the white flour diet had the lowest food intake, weight gain, fecal excretion and intestinal fermentation. The most important result was that Mg and Fe status were drastically lower in rats fed the white flour diet than in those fed whole flour or control diets. The status of these both elements were significantly improved by the mineral supplementation of white flour. There were no major significant differences between mineral-supplemented white flour and whole flour groups in mineral status. Furthermore, bone mineral densities (total, metaphyseal and diphyseal) were significantly lower in rats fed white flour diet compared to the other diet groups, while no significant difference was observed between the mineral-supplemented white flour, whole flour or control diet groups. In conclusion, the present work shows clearly the importance of mineral-supplementation of white wheat flour to sustain an adequate intake of minerals. Our results indicate also that the whole wheat flour did not negatively alter mineral bioavailability, in comparison to mineral supplemented white flour. Clinical studies are still needed to confirm these rat results in human.     

Molecular evolution of bat color vision genes

The two suborders of bats, Megachiroptera (megabats) and Microchiroptera(microbats), use different sensory modalities for perceivingtheir environment. Megabats are crepuscular and rely on a well-developedeyes and visual pathway, whereas microbats occupy a nocturnalniche and use acoustic orientation or echolocation more thanvision as the major means of perceiving their environment. Inview of the differences associated with their sensory systems,we decided to investigate the function and evolution of colorvision (opsin genes) in these two suborders of bats. The middle/longwavelength (M/L) and short wavelength (S) opsin genes were sequencedfrom two frugivorous species of megabats, Haplonycteris fischeriand Pteropus dasymallus formosus, and one insectivorous speciesof microbat, Myotis velifer. Contrary to the situation in primates,where many nocturnal species have lost the functional S opsingene, both crepuscular and strictly nocturnal species of batsthat we examined have functional M/L and S opsin genes. Surprisingly,the S opsin in these bats may be sensitive to UV light, whichis relatively more abundant at dawn and at dusk. The M/L opsinin these bats appears to be the L type, which is sensitive tored and may be helpful for identifying fruits among leaves orfor other purposes. Most interestingly, H. fischeri has a recentduplication of the M/L opsin gene, representing to date theonly known case of opsin gene duplication in non-primate mammals.Some of these observations are unexpected and may provide insightsinto the effect of nocturnal life on the evolution of opsingenes in mammals and the evolution of the life history traitsof bats in general.     

Changes in color and texture of wheat noodles during chilled storage

Wheat noodles cooked for different periods of time were stored at 5 °C, and color changes in their cross sections were quantitatively assessed by digital image analysis. The color of noodles with flattened moisture distributions whitened greatly during the early stages of chilled storage due to the retrogradation of starch, with the color change showing a significant correlation with the changes in noodle fragility. Color changes were also measured for wheat noodles and noodles containing modified starch with internal moisture distributions, and local changes within the noodles were kinetically analyzed. The addition of modified starch significantly reduced the color change in the noodle interior, where the moisture content was relatively low. Scanning calorimetric measurements indicated differences in the gelatinized state of modified starch and original wheat starch at low moisture contents, which affected the rate of color change in the interior of noodles containing modified starch.