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。     

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。     

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。     

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.     

脑啡肽基因多态性与阿尔茨海默病的文献综合分析

阿尔茨海默病(Alzheimer’s disease,AD)是痴呆最常见的类型,以记忆减退、认知障碍和行为异常为主要临床表现,可能与遗传和环境因素有关。研究认为β淀粉样蛋白肽(amyloid beta,Aβ)的蓄积是AD发病的中心环节。脑啡肽(Neprilysin,NEP)作为脑内Aβ的主要降解酶,是AD研究的热点。现阶段关于NEP基因多态性和AD发病的关联研究颇多,但尚未证实两者间的关系,存在许多不一致的结论。该文利用文献检索系统,对NEP基因多态性与AD临床相关性的文献进行检索分析,了解目前研究现状,分析可能造成的原因,探索进一步的研究方案。     

DNA restriction-fragment variation in the gene family encoding high molecular weight (HMW) glutenin subunits of wheat

Restriction enzyme digests of DNA from nullisomic-tetrasomic and intervarietal chromosome substitution lines of wheat were probed with a high molecular weight (HMW) glutenin cDNA. Three restriction endonucleases were used to investigate restriction-fragment differences among five wheat varieties. The results suggest that the hybridizing fragments contain single gene copies and permit the identification of the subunit encoded by each gene. Restriction-fragment variation associated with previously established allelic differences between varieties was observed. Also, there is a clear relationship between the electrophoretic mobility of a HMW subunit and the length of the central repetitive section of the gene encoding it. These results are discussed with reference to the evolution of the HMW glutenin gene family and the uses of restriction-fragment variation in plant breeding and genetics.N.P.H. was supported by a MRC Training Fellowship in Recombinant DNA Technology and a grant from the Perry Foundation. D.B. is supported by EEC Contract GBI-4-027-UK.     

Biochemical and molecular characterization of gliadins

Gliadins account for about 40–50% of the total proteins in wheat seeds and play an important role in the nutritional and processing quality of flour. Usually, gliadins can be divided into α-(α/β), γ-, and ω-groups, whereas the low-molecular-weight (LMW) gliadins are novel seed storage proteins. The low-molecular-weight glutenin subunits (LMW-GSs) are also designated as gliadins in a few publications. The genes encoding gliadins are mainly located on the short arms of group 6 and group 1 chromosomes, and not evenly distributed. Repetitive sequences cover most of the uncoding regions, which attributed greatly to the evolution of wheat genome. The primary structure of each gliadin is divided into several domains, and the long repetitive domains consist of peptide motifs. Conserved cysteine residues mainly form intramolecular disulfide bonds. The rare potential intermolecular disulfide bonds and the long repetitive domains play an important role in the quality of wheat flour. There is a general idea that gliadin genes, even prolamin genes, have a common origin and subsequent divergence leads to gene polymorphism. The γ-gliadins are considered to be the most ancient of the wheat prolamin family. Several elements in the 5′-flanking (e.g., CAAT and TATA box) and the 3′-flanking sequences have been detected, which has been shown to be necessary for the proper expression of gliadins. Published in Russian in Molekulyarnaya Biologiya, 2006, Vol. 40, No. 5, pp. 796–807. The text was submitted by the authors in English.     

Chemical and Nutritional Properties of Hypoallergenic Wheat Flour

The chemical and nutritional properties were investigated of hypoallergenic wheat flour (HWF) prepared by the cellulase-actinase treatment. HWF was composed mainly of oligopeptides and free amino acids, and its average molecular weight was lower than 1,000. Feeding tests on rats showed that, with respect to the PER, GOT and GPT activities and other nutritional indices, the HWF diet was almost equivalent to the control diet which had been prepared from normal wheat flour (NWF). No abnormality was apparent in the main organs after the HWF diet had been fed for 3 weeks. The small intestinal absorption of the HWF diet was found normal by measuring the free amino acid concentration in the intestinal tract and in the portal vein plasma. These data suggest that te absorption of amino acids from the HWF diet was comparable with or more efficient than that from a simulated free amino acid diet.     

主要组织相容性复合体(MHC)基因的研究概况

主要组织相容性复合体(MHC)因其在免疫方面的重要作用而倍受免疫学家重视．随着研究的不断深入,了解到MHC是一个高度多态的基因群,它广泛分布于各种脊椎动物体内．MHC除了具有免疫功能外,还在其它许多方面起作用．MHC基因的多态性是最受关注的特征,尤其是Ⅱ类基因．根据MHC基因的多态性,可以在遗传、进化、行为、保护及生态等许多方面对其进行研究．就目前的研究情况,在结构、功能及应用等方面对MHC作了介绍．     

花色多样性与变异的研究进展

花的颜色不仅在不同物种之间有着丰富的多样性,同一物种的不同居群或个体之间也有着花色的多态性,同一花中的不同器官甚至同一类型的器官也有颜色差异。了解花色多样性的形成和维持机制,有助于揭示花的演化。经典的观点认为,花色是植物提供给传粉者的视觉信号,能促进传粉和提高觅食效率。在分析花色多样性的基础上,本文介绍了4种不同的研究方法,并论述了当前解释花色多样性的3个主要假说。提出今后的研究有必要结合系统发育的分析方法,综合考虑传粉者、植食动物、物理环境等多个因子的选择作用,才能深入理解花色的多样性与演化。     

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).     

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.     

Novel Method for Producing Hypoallergenic Wheat Flour by Enzymatic Fragmentation of the Constituent Allergens and Its Application to Food Processing

A novel method is proposed to produce hypoallergenic wheat flour suitable for patients allergic to wheat. Wheat flour was mixed with a cellulase solution, and the mixture was incubated at 50°C for 1 h to hydrolyze the carbohydrate allergens. The hydrolysate was further incubated with actinase at 40°C for 1 h while gently stirring to decompose the proteinaceous allergens. The product was evaluated for its allergenicity by an enzyme-linked immunosorbent assay, the results of which suggested negative allergenicity in most cases. The product changed to a batter state that was difficult to process by the usual methods. Gelatinization of the starch in the product and the addition of a surfactant were beneficial for food processing.     

The effect of color polymorphism on mortality in the aphidMacrosiphoniella yomogicola

We examined body color polymorphism in the aphidMacrosiphoniella yomogicola from July to September 1993. We classified body color into eight types: green 1, green 2, red 1, red 2, white, orange, yellow and mist. The frequencies of body color varied with time and among patches of the host plant, yomogi (Artemisia spp.). Color diversity within a shoot was calculated using the Shannon diversity index. Of five usable data sets, three showed negative relationships between color diversity and mortality. The regression coefficients for two of these relationships were significant. No significant relationship between mortality and the number of aphids was found. The color diversity was not significantly related to a particular body color found on a yomogi shoot. Color polymorphism may be maintained because selection may favor a high color diversity on the host plant shoot.