小麦高分子量麦谷蛋白亚基的遗传变异与小麦加工品质改良

高分子量麦谷蛋白亚基（HMW-GS）是小麦胚乳中一种具有多态性的蛋白质组分,在面团中它们可以通过相互之间或与低分子量麦谷蛋白亚基（LMw-Gs）之间形成二硫键来组成麦谷蛋白多聚体。由于其在小麦面粉加工所需的粘性和弹力方面具有极其重要的作用,过去几十年间在小麦加工品质相关蛋白研究方面的工作大多数集中在高分子量麦谷蛋白亚基上。近几年在高分子量麦谷蛋白亚基及其编码基因的鉴定、基因的遗传变异以及不同变异在小麦加工品质中的作用方面进行了大量研究。本文对近几年在HMW-GS领域的研究进展进行综述并且重点讨论HMW-GS的变异及其对小麦品质育种的重要意义。     

小麦高分子量麦谷蛋白亚基5基因序列

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甘肃省春小麦品种高分子量麦谷蛋白亚基组成分析

应用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)技术,对甘肃省121个普通小麦品种(包括地方品种、育成品种和引进品种)高分子量谷蛋白亚基构成、不同等位基因间亚基变异及出现频率系统分析的结果表明,甘肃省春小麦品种HMW-GS等位基因Glu-Al编码1、2*、N(缺失)三种亚基,Glu-B1 编码 7 8、7 9、17 18、22、7、8、14 15七种亚基,Glu-D1编码2 12、2 11、5 10、2 10、10、4 11、3 12、N八种亚基,频率最高的亚基分别是Null(81.0%)、7 8(86.0%)、2 12(60.0%);一些优质亚基在现有品种中都存在,如甘春20、高台紫麦子等,作亲本用于品质改良有很大潜力,而且少数罕见亚基7、8、11也存在;不同来源的春小麦品种HMW-GS组成比较,优质亚基组成类型如1、7 8、5 10,1、17 18、5 10在育成品种中出现频率较高.     

湖北推广小麦品种(系)高分子量麦谷蛋白亚基组成分析

应用SDS-PAGE技术分析了45份湖北推广小麦品种(系)籽粒的高分子量麦谷蛋白亚基组成。40份材料的高分子量麦谷蛋白亚基组成为同质,5份为异质。在Glu-1位点共检测到9种等位基因变异类型,其中Glu-A1位点有“1、2^ 、Null”3种变异类型,Glu-B1位点有“7、7 8、7 9、14 15”4种,Glu-D1位点有“2 12、5 10”2种。“Null、7 8、2 12”是主要亚基,它们的频率分别是62．5％、60％和72．5％。亚基组合类型有12种,其中(Null,7 8,2 12)亚基组合占30．0％,(1,7 8,2 12)、(1,14 15,2 12)、(Null,7 9,2 12)、(Null,7 8,5 10)4种组合的频率都在10％以上,这5种亚基组合占总组合的72．5％。供试小麦材料品质评分在5～10之间,平均评分为7．0。含5 10亚基的品种(系)所占比例低,是湖北小麦烘烤品质较差的部分原因。     

西北春麦区小麦地方品种高分子量麦谷蛋白亚基组成分析

为了给品质改良提供基础材料,并了解西北春麦区小麦地方品种的遗传多样性,采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)方法,分析了493份小麦地方品种的高分子量麦谷蛋白亚基(HMW-GS)的组成.结果表明:在供试材料中,Glu-1位点共有26个等位基因,其中Glu-A1位点3个,Glu-B1位点9个,Glu-D1位点14个,亚基null、7+8、2+12在各自的位点上出现频率最高,分别达到了94.53%、92.92%、86.24%;亚基组成类型共有30种,主要为null/7+8/2+12,频率达79.76%;同时筛选出一些含有1、2*、13+16、14+15、5+10、1.5+10等优质亚基或亚基对的材料,可作为优质基因源;西北春麦区小麦地方品种间Glu-1位点的遗传多样性,以Glu-D1位点最高,其次是Glu-B1位点,Glu-A1位点最低.     

小麦低分子量麦谷蛋白亚基功能标记研究进展

小麦是我国主要的粮食作物之一,籽粒中的低分子量麦谷蛋白对于小麦面包的加工品质具有重要的作用。近年来,利用分子标记技术检测小麦低分子量麦谷蛋白亚基（low molecular weight glutenin subunit,LMW-GS）的类型和组成已成为小麦品质改良的研究热点之一。主要综述了小麦低分子量麦谷蛋白亚基基因和蛋白质的结构特征、分类以及功能标记的研究进展,讨论了开发利用小麦Glu-A3、Glu-B3、Glu-D3位点LMW-GS功能标记的意义及存在的问题,并强调了LMW-GS分子标记检测技术的革新及亚基类型的完善对小麦品质改良的重要性,以期加速LMW-GS功能标记在优质小麦育种工作中的应用进程。     

小麦高分子量麦谷蛋白亚基分离方法的研究

小麦高分子量麦谷蛋白亚基（ＨＭＷ－ＧＳ）与小麦面包烘烤质量和面粉的加工特性密切相关,ＳＤＳ－ＰＡＧＥ是其常用的分离方法之一。ＳＤＳ－ＰＡＧＥ方法一般分为２类：第一类采用１１％和５％浓度的胶,后者用于分离２亚基和２＾＊亚基,该种方法常使用碱性提取液,需要２次电泳过程,且在５％浓度的胶中ＨＭＷ－ＧＳ易于和麦醇蛋白混淆;另外一类ＳＤＳ－ＰＡＧＥ采用梯度胶,配合使用银染方法,制梯度胶则使用梯度仪及磁力搅拌     

西藏半野生小麦高分子量麦谷蛋白亚基组成分析

应用SDS-PAGE分析了50份西藏半野生小麦(Triticum aestivum ssp.tibetanum Shao)的高分子量麦谷蛋白亚基等位基因组成。结果表明,43份材料的HMW-GS组成是同质的,7份材料为异质。供试材料共有7种HMW GS组合,以Null、7 8、2 12为主要类型,占所分析材料的68．4％。在Glu-1位点共检测到10种等位基因,Glu- A1位点2种,Glu～B1位点4种,Glu～D1位点4种。Null(96％)、7 8(80．4％)和2 12(94．9％)分别是Glu-A1、 Glu-B1和Glu～D1位点上主要的等位基因。在Glu-B1位点还新发现2个亚基,暂时分别命名为8*和7**。说明西藏半野生小麦中存在着较广泛的HMW-GS等位基因变异,是小麦品质育种潜在的可利用的遗传资源。     

SDS-PAGE分析转基因小麦与主栽小麦杂交后代的高分子量麦谷蛋白亚基

目的:高分子量麦谷蛋白亚基(HMW-GS)1Ax1、1Dx5是对小麦面包烘烤品质有重要影响的优质亚基。将转基因小麦株系与普通小麦栽培品种常规杂交并快速筛选后代,以选育含有外源优质亚基的主栽小麦品系。方法:将分别含有1Ax1、1Dx5亚基的转基因小麦株系B102-1-2、B73-6-1与3种普通小麦主栽品种鄂恩1号、鄂麦12号、日喀则8号常规杂交,用不连续SDS-PAGE方法鉴定12组杂交组合(正反交)F1代311颗籽粒的HMW-GS。结果:不连续SDS-PAGE分析大量子代带型,能够快速鉴定筛选出具有优质亚基的株系,转基因获得的外源优质HMW-GS基因在大部分F1子代中能够共显性遗传。结论:常规杂交育种能使外源基因有效地整合进主栽小麦的基因组中,进一步分析后代遗传的稳定性和遗传规律就可以培育出优质的新品种;不连续SDS-PAGE快速筛选优质亚基的株系具有可操作性和实用性。     

小麦低分子量麦谷蛋白亚基分离条件优化

目的：优化一种有效分离小麦LMW-GS的实验条件。方法：以面包小麦L88-6作为材料,采用SDS-PAGE技术,通过对麦谷蛋白提取液、分离胶浓度、分离时间、电泳缓冲液等条件进行实验比较。结果与结论：含0.3mol/LNaI和1.4%4-VP的麦谷蛋白提取液能有效提取LMW-GS成分,分离胶浓度为T=14%C=3%、分离时间为40h、Tris-硼酸或Tris-甘氨酸电极缓冲液的分离条件分离效果好、重复性好、简单易行,为小麦低分子量麦谷蛋白亚基深入研究的第一个限速步骤提供了良好的解决方案。     

不同硬度类型小麦高分子量谷蛋白亚基组成及遗传多样性分析

为了在小麦品质育种中充分利用品种资源,以引进的57份小麦品种(系)为试验材料,采用SDS-PAGE和单籽粒硬度仪(SKCS)分析了这些品种(系)的高分子量谷蛋白亚基(HMW-G S)组成及其籽粒硬度.共检测到13种亚基和21种亚基组合,30份材料具有5 10亚基,10份2*,9份17 18,1份13 16.5 10和2*在硬质麦中出现的频率较混合麦高,在软质麦中的频率最低,17 18在混合麦中的频率较高.HMW-G S组合中,N u ll、7 9、2 12和1、7 8、2 12的频率较高,分别为17.5%和14.0%,个别品种还同时聚合有1A、1B、1D上的优质亚基.参试品种(系)含硬质麦32份(1级20份、2级12份),混合麦15份(2级3份,3级12份),软质麦10份(4级6份,5级4份),籽粒硬度的分布范围为12~74.春小麦和冬小麦材料N e i s平均遗传变异系数分别为0.550 8和0.573 3,表明春小麦的高分子量谷蛋白位点的遗传变异略低于冬小麦;春小麦和冬小麦A、B和D基因组的N e i s平均遗传变异系数分别为0.497 5、0.648 7和0.540 3,说明G lu-B 1位点的遗传多样性最高,其次是G lu-D 1位点,G lu-A 1位点最低.     

HMW-GS组成不同小麦品种各种亚基形成和积累规律研究

以3个HMW—GS组成不同的冬小麦品种为材料,研究了籽粒形成过程中亚基形成及积累表达规律。结果表明,不同亚基形成时间存在差异,Glu—D1、Glu—B1编码的亚基约在开花后第13天最早出现,Glu—A1编码的1亚基形成较晚。在灌浆期亚基已基本全部形成,但积累较慢;花后第20天后进入成熟过程,高分子量麦谷蛋白亚基大量迅速积累,开花第28～31天积累量达最高,之后含量有所下降。同一品种内不同亚基积累量不同,形成较早的Glu—D1、Glu—B1编码的亚基积累量最多,Glu—D1编码的X型亚基在所有供试品种中都有最多量的积累。     

小麦种子活力性状的遗传变异和相关研究

本研究利用12个普通小麦品种对10个种子活力性状的遗传变异和相关研究,表明除正常幼苗百分率外,其余种子活力性状在品种间均存在显著的差异。种子贮藏物质转换效率、电导率两个性状问及与其它性状均无显著的遗传相关,因此对他们的选择不会影响到其它性状。通径分析表明幼苗干重主要取决于种子贮藏物质转换效率、种子贮藏物质利用速率;发芽指数主要由平均发芽时间决定。电导率、发芽势、幼苗于重、种子干重、发芽指数、种子贮藏物质消耗比率6个性状表现中到高的遗传力、遗传变异系数和相对遗传进展,指明通过遗传育种手段改良这些性状是可能的。     

HMW-GS的SDS-PAGE图谱在小麦品质评价中的应用

采用SDS—PAGE技术对陕西关中地区各时期大面积推广小麦品种、品种资源和新品系的HMW—GS组成进行了分析。在该地区50多年大面积推广的33个品种中,检测出9种HMW亚基(对)及其组成;品种HMW—GS的评分在5～10分之间,平均6．9分;4个时期品种HMW-GS的平均评分有升有降,优质亚基出现的频率普遍偏低;向小麦品种中聚合多种优质HMW—GS将成为陕西关中未来小麦育种的主要目标之一。53种小麦品种资源的亚基或亚基对组合类型比较丰富,具有一批携带优质亚基5 10、1、2*、7 8、14 15或17 18等资源。8个新选品系中,有4个品系携带了多种优质亚基,其中3个品系HMW—GS的评分为10分;Q1043已被审定通过,目前正在陕西关中推广种植。实践证明,采用SDS—PAGE方法对生产上推广品种、品种资源和新选品系的HMW—GS变异研究,有助于在短时间内了解生产上推广小麦品质生产现状、制订育种目标、选配亲本和品系品质性状筛选,是一种非常实用的品质快速检测方法。     

应用RAFD标记研究不同生态区谷子品种的遗传差异

应用RAPD标记对19份国内不同生态区的谷子品种的遗传变异进行了研究。结果表明：分子水平上,不同生态区的谷子品种间存在一定的遗传差异,但遗传差异程度并不高。11个随机引物共扩增出54条多态性带,不同引物扩增的带数差异较大,每个引物可扩增2—8条多态性带,平均每个引物扩增出4．91条多态性带。引物1050扩增的多态性带最多(8条)。聚类结果表明,基于RAPD标记分析的遗传聚类群与生态类型有很大的一致性。     

Genetic diversity in Chinese modern wheat varieties revealed by microsatellite markers

Genetic diversity of 1680 modern varieties in Chinese candidate core collections was analyzed at 78 SSR loci by fluorescence detection system. A total of 1336 alleles were detected, of which 1253 alleles could be annotated into 71 loci. For these 71 loci, the alleles ranged from 4 to 44 with an average of 17.6, and the PIC values changed from 0.19 to 0.89 with an average of 0.69. (1) In the three genomes of wheat, the average genetic richness was B>A>D, and the genetic diversity indexes were B>D>A. (2) Among the seven homoeologous groups, the average genetic richness was 2=7>3>4>6>5>1, and the genetic diversity indexes were 7>3>2>4>6>5>1. As a whole, group 7 possessed the highest genetic diversity, while groups 1 and 5 were the lowest. (3) In the 21 wheat chromosomes, 7A, 3B and 2D possessed much higher genetic diversity, while 2A, 1B, 4D, 5D and 1D were the lowest. (4) The highest average genetic diversity index existed in varieties bred in the 1950s, and then it declined continually. However, the change tendency of genetic diversity among decades was not greatly sharp. This was further illustrated by changes of the average genetic distance between varieties. In the 1950s it was the largest (0.731). Since the 1960s, it has decreased gradually (0.711, 0.706, 0.696, 0.695). The genetic base of modern varieties is becoming narrower and narrower. This should be given enough attention by breeders and policy makers.     

Genetic diversity in Chinese modern wheat varieties revealed by microsatellite markers

Genetic diversity of 1680 modern varieties in Chinese candidate core collections was analyzed at 78 SSR loci by fluorescence detection system. A total of 1336 alleles were detected, of which 1253 alleles could be annotated into 71 loci. For these 71 loci, the alleles ranged from 4 to 44 with an average of 17.6, and the PIC values changed from 0.19 to 0.89 with an average of 0.69. (1) In the three genomes of wheat, the average genetic richness was B>A>D, and the genetic diversity indexes were B>D>A. (2) Among the seven homoeologous groups, the average genetic richness was 2=7>3>4>6>5>1, and the genetic diversity indexes were 7>3>2>4>6>5>1. As a whole, group 7 possessed the highest genetic diversity, while groups 1 and 5 were the lowest. (3) In the 21 wheat chromosomes, 7A, 3B and 2D possessed much higher genetic diversity, while 2A, 1B, 4D, 5D and 1D were the lowest. (4) The highest average genetic diversity index existed in varieties bred in the 1950s, and then it declined continually. However, the change tendency of genetic diversity among decades was not greatly sharp. This was further illustrated by changes of the average genetic distance between varieties. In the 1950s it was the largest (0.731). Since the 1960s, it has decreased gradually (0.711, 0.706, 0.696, 0.695). The genetic base of modern varieties is becoming narrower and narrower. This should be given enough attention by breeders and policy makers.     

Genetic variation for outcrossing among Caenorhabditis elegans isolates

The evolution of breeding systems results from the existence of genetic variation and selective forces favoring different outcrossing rates. In this study we determine the extent of genetic variation for characters directly related to outcrossing, such as male frequency, male mating ability, and male reproductive success, in several wild isolates of the nematode Caenorhabditis elegans. This species is characterized by an androdioecious breeding system in which males occur with hermaphrodites that can either self-fertilize or outcross with males. We find genetic variation for all characters measured, but also find that environmental variation is a large fraction of the total phenotypic variance. We further determine the existence of substantial genetic variation for population competitive performance in several laboratory environments. However, these measures are uncorrelated with outcrossing characters. The data presented here contribute to an understanding of male maintenance in natural populations through their role in outcrossing.     

Quality differences between NILs of wheat variety Long 97-586 possessing HMW-GS 7+8 and 7

The high molecular weight glutenin subunits (HMW-GS) 7+8 were introduced into the Long 97–586 (1,7,2+12) wheat variety (Triticum aestivum) by 5 consecutive backcrosses with biochemical marker–assisted selection.Nearly isogenic lines (NILs) of HMW-GS 7 and 7+8 were obtained,and the NILs were planted in the experimental field at the Crop Breeding Institute of Heilongjiang Academy of Agricultural Science in 2004–2006.The field experiments were designed using the two-column contrast arrangement method with six replicates in 2004–2005 and four replicates in 2006.The result of three years experiments showed that the differences between NILs of Long 97–586 with subunit 7 and those with subunits 7+8 in the quality parameters of flour protein content and dry gluten content were negligible (P0.1).However,the differences in some of the quality parameters were remarkably significant (P0.01),including wet gluten content,ratio of wet gluten/dry gluten,gluten index,Zeleny sedimentation,ratio of sedimentation/dry gluten,and the farinogram parameters of water absorption,development time,stability,breakdown time and degree of softening.The difference between NILs with subunits 7+8 and subunit 7 was significant (P0.05) on the alveogram W value and had a critical value (P=0.05) on the alveogram P value in 2006.The results show that HMW-GS 7+8 is far superior to HMW-GS 7 in terms of baking quality.The possibilities of using subunits 7+8 and subunit 7 in breeding strong and weak gluten wheat varieties are discussed in this paper.