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1.
The entire USDA‐ARS maintained collection of 650 accessions of proso millet (Panicum miliaceum L.) was evaluated for the presence of accessions with waxy (amylose‐free) endosperm starch. Six accessions, five of which derived from mainland China, were identified. Segregation ratios for waxy endosperm were evaluated in F2 and F3 populations derived from crosses between two waxy accessions, PI 436625 (Lung Shu 16) and PI 436626 (Lung Shu 18), and several wild‐type accessions. The waxy trait was found to be under the control of duplicate recessive alleles at two loci, herein designated wx‐1 and wx‐2. Wild‐type alleles at these loci were designated Wx‐1 and Wx‐2. Iodine‐binding revealed a mean grain‐starch amylose concentration of 3.5% in waxy lines and 25.3% in wild‐type proso. Expression of the granule‐bound starch synthase (waxy protein) in waxy lines was reduced to approximately one‐tenth that of wild‐type accessions. The waxy accessions identified now are available for the introgression of this trait into breeding lines adapted to the Great Plains of North America.  相似文献   

2.
Waxy (Wx) protein is a key enzyme for synthesis of amylose in endosperm. Amylose content in wheat grain influences the quality of end‐use products. Seven alleles have been described at the Wx‐D1 locus, but only two of them (Wx‐D1b, Wx‐D1e) were genotyped with codominant markers. The waxy wheat line K107Wx1 developed by treating ‘Kanto 107’ seeds with ethyl methanesulphonate carries the Wx‐D1d allele. However, no molecular basis supports this nomenclature. In the present study, DNA sequence analysis confirmed that a single nucleotide polymorphism in the sixth exon of Wx‐D1 changed tryptophan at position 301 into a termination codon. Based on this sequence variation, a PCR‐based KASP marker was developed to detect this point mutation using 68 BC8F1 plants and 297 BC8F2 lines derived from the cross ‘Ningmai 14’*9/K107Wx1. Combined with codominant markers for the Wx‐A1 and Wx‐B1 alleles, waxy and non‐waxy near‐isogenic lines were distinguished. The KASP marker was efficient in identifying the mutant allele and can be used to transfer waxiness to elite lines.  相似文献   

3.
To characterize superior genotypes for the white Japanese noodle, endosperm starch properties including amylose content, flour peak viscosity and starch-granule bound Waxy (Wx) proteins were compared using several cultivars preferred for noodle manufacture. Amylose contents from three seasons trials and flour peak viscosity from two seasons trials varied among cultivars. Low amylose content was a common property in the noodle cultivars, whereas a high peak viscosity was not always the case. When the Wx proteins were analyzed by sodium dodecylsulfate polyacrylamide gel electrophoresis, a clear reduction in the amount of low molecular weight protein or a lack of the high molecular weight protein occurred in the noodle cultivars. Segregation of Wx proteins was detectable in a B1F1 population, indicating that the Wx protein analysis has a potential as a surrogate of selecting low amylose genotypes in early generations.  相似文献   

4.
The granule-bound starch synthase (GBSS I) encoded by the Wxgenes, is involved in amylose synthesis. For analyses of mechanisms of amylose synthesis and associated starch properties in hexaploid wheat, eight possible genotypes having different combinations of the three null alleles at the Wx loci with a common genetic background are a prerequisite. A near-isogenic population of doubled haploid (DH) lines was produced from Chinese Spring × waxy Chinese Spring F1 plants using the wheat × maize method. The Wx protein phenotypes of the DH progeny were examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and found that the null alleles at each of the three Wx loci segregated in a Mendelian fashion. A field trial demonstrated no differences between the eight types for ear emergence time, plant height and grain yield traits. Amylose content in the endosperm starch was highest in the wild type while lowest in the waxy type having no Wx proteins. Comparison between single null types and double null types indicated that the amylose synthesis capacity of Wx-A1a allele is the lowest. Pasting properties of starch are the highest in the waxy type, followed by the double null types. Consequently, both peak viscosity and breakdown were negatively correlated with amylose content. The chain-length distribution analysis of amylopectin structure revealed no clear difference among the eight types,suggesting that the reduced GBSS I activity due to introgression of the null Wx alleles does not affect either the chain length or the degree of branching of amylopectin. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

5.
Polymorphism of waxy proteins in Spanish durum wheats   总被引:3,自引:0,他引:3  
A collection of 547 durum wheats (103 cultivars and 444 landraces) from Spain was analysed for waxy protein composition. The electrophoretic patterns showed low polymorphism. At the Wx‐A1 locus, 99.8% of the wheats had the Wx‐Ala allele and only one had the null Wx‐Alb allele. The Wx‐Bl locus was more polymorphic and four different alleles were detected: Wx‐Bla (41.3%), Wx‐Blc (42.6%), a new allele, not detected before in bread wheat and named Wx‐Blf (16.0%), and the null Wx‐Blb allele, found for the first time in one durum wheat. Eleven durum wheats with different allelic composition at the Wx‐l loci were analysed for amylose content. Wheats with the Wx‐Bla allele had a lower amylose content than those with Wx‐Blc or Wx‐Blf. The lowest amylase content was found in the only durum wheat having the null Wx‐Blb allele.  相似文献   

6.
青稞Wx基因多态性与直链淀粉含量的关系   总被引:1,自引:0,他引:1  
以150份青稞品种为材料, 采用碘–碘化钾染色法进行表型鉴定, 筛选出含糯性基因型的4份参试材料, 分别是品种IG107028、Puebla、互助双槽人和APM-HC1905。经双波长法测定, 150份参试材料的直链淀粉含量(AC)为12.4%~38.5%, 平均26.0%; 4份糯性参试材料的直链淀粉含量为12.4%~18.6%, 平均16.7%。以直链淀粉含量差别较大的51份材料为模板, 利用引物P4进行扩增, 结果P4引物在51份材料中均有扩增产物出现, 且随着参试材料直链淀粉含量的增大, 其扩增产物的分子量有逐渐增大的趋势, Wx基因位点表现出多态性, 二者呈正相关。根据带型将51份材料分成I型、II型、III型和IV型, 其扩增片段分子量分别为457、481、489和491 bp, 各类型品种的直链淀粉含量分别为12%~27%、29%~30%、31%~35%和36%~38%。P4可作为糯性青稞品种选育的辅助选择标记。  相似文献   

7.
为明确不同Wx基因对小麦直链淀粉含量的影响以及筛选面条品质优异的基因型,以糯小麦品系Caiwx (aabbdd)为3个Wx基因隐性突变供体亲本,以扬麦01-2 (AABBDD)为轮回亲本,利用连续回交结合花粉碘染、STS标记和同工酶标记检测方法,创制了8种Wx基因纯合基因型的近等基因系,其基因型分别为AABBDD、AABBdd、AAbbDD、AAbbdd、aaBBDD、aaBBdd、aabbDD和aabbdd。利用这些基因型探讨了不同Wx基因对直链淀粉含量及面条感官品质的影响。结果表明,各系的直链淀粉含量为0.9%~24.8%,系间差异显著;糯小麦型(aabbdd)直链淀粉含量最低,双缺失型和单缺失型其次,双缺失型中aaBBdd型含量最高,单缺失型中AAbbDD型含量最低,表明Wx-B1对直链淀粉的合成作用最大。糯小麦型面条的色泽、表观、软硬度、黏性、韧性得分以及总分显著低于其他类型及轮回亲本扬麦01-2;单缺失型面条的色泽、表观得分、总分显著高于轮回亲本扬麦01-2,其中aaBBDD型面条品质表现突出,与市售优质面条粉“雪花粉”制作的面条得分相当,而其他7种基因型及轮回亲本扬麦01-2的面条评分均显著低于雪花粉。说明可以通过遗传操作Wx基因培育优质面条小麦品种。  相似文献   

8.
T. Nakamura    M. Yamamori    H. Hirano  S. Hidaka 《Plant Breeding》1993,111(2):99-105
Two cultivars with a low amylose content, Kanto107 (K107) and K79, were discovered in Japanese common wheat (Triticum aestivum L.). The amount of Wx protein, identified as a single major starch granule-bound protein of about 61 kD by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), was greatly decreased in those two cultivars. Analysis of their Wx protein with a modified SDS-PAGE and two dimensional-PAGE showed that two of the three Wx proteins, produced by Wx-A1 and Wx-B1 loci, were not detected. It was thus concluded that only one locus, Wx-D1, was active in the two low amylose cultivars. These mutants were termed “partial waxy mutants” and considered to be very useful material for breeding waxy wheat.  相似文献   

9.
为得到一种鉴别糯质谷子的分子标记方法,用于优质谷子糯质资源的利用及糯质品种的选育。通过对糯性谷子十里香与梗性谷子豫谷1号配制的F2群体的F3种子胚乳进行碘液检测,结果显示:深蓝色与棕红色胚乳单株数的比例符合3∶1,说明糯质对梗质是由单基因控制的隐性性状。利用糯质分型引物对十里香基因组进行PCR扩增和产物测序,结果表明,十里香的糯性是由Ⅳ型糯质基因控制,即由TSI-2转座子插入到淀粉合成酶基因(Si006103m)内元1形成。根据该糯质基因设计出2对In Del标记引物waxy-TSI2/int1和waxy-int1-1F/4R,扩增谷子基因组DNA,若waxy-TSI2/int1引物组合能扩增出984 bp的扩增片段,并且waxy-int1-1F/4R引物组合不能扩增出540 bp的扩增片段,则该材料为含Ⅳ型糯质基因的糯质谷子。最后,利用该标记组合从100份谷子资源中鉴定到2份属于Ⅳ型糯质基因控制的糯质材料。可见,该标记组合可以准确鉴别谷子Ⅳ型糯质基因。  相似文献   

10.
The waxy phenotype, associated with endosperm containing little or no amylose, has been recognized in sorghum (Sorghum bicolor L. Moench) since 1933. Although variants of the waxy gene are well characterized in other cereals, the waxy trait has been assumed to be controlled by a single allele, wx, in sorghum. Recent improvements in technologies encourage re-examination of the waxy sorghums. The objectives of this research were therefore to identify and characterize sorghum lines with differing waxy alleles and to describe the actions of those alleles in crosses. Grain of eight waxy sorghum lines (BTxARG1, BTx630, Tx2907, B.9307, 94C274, 94C278, 94C289, 94C369), three wild-type checks (BWheatland, RTx430, BN122), and F2 families from crosses among a subset of these lines were evaluated for presence or absence of granule-bound starch synthase (GBSS), the gene product of the wx locus, and wild-type vs. waxy endosperm. The F2 segregation ratios were tested for fit to a 3:1 ratio using Chi-square analyses. Two distinctly different naturally occurring waxy alleles were identified: One with no GBSS (GBSS−), and one with apparently inactive GBSS present (GBSS+). We propose that the waxy allele with no GBSS be designated wxa, and that waxy allele with apparently inactive GBSS present be designated wxb. These two alleles are located in close proximity on the waxy locus. The wxb allele is dominant to the wxa allele in terms of GBSS production, and both are recessive to the wild-type Wx in terms of amylose content. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.  相似文献   

11.
M. Yamamori 《Euphytica》2009,165(3):607-614
In common and durum wheats (Triticum aestivum L. and T. durum Desf.), variant waxy (Wx) alleles have been reported for three Wx proteins (Wx-A1, -B1 and -D1), responsible for amylose synthesis in flour starch. Five variant alleles, Wx-A1c, -A1e, -B1c, -B1d and -D1c, were examined to elucidate their effects on amylose content in flour starch. Common wheat lines carrying a Wx protein produced by one variant (e.g., Wx-A1c) and one control (e.g., Wx-A1a) allele were bred and their starches were compared. Results showed that Wx-A1e did not produce amylose (waxy phenotype), whereas three alleles (Wx-A1c, -B1c and -B1d) reduced amylose, and -D1c might have increased it slightly. Most data on blue value, swelling power and starch paste clarity in water and dimethyl sulphoxide also suggested the variant Wx alleles either reduced or increased amylose content.  相似文献   

12.
翟红梅  田纪春 《作物学报》2007,33(7):1059-1066
以小麦品种藁城8901为母本,糯麦1号为父本,用“单粒传”法构建了一个含有8种Wx基因突变类型的重组自交系群体 (RIL) 。应用改良的SDS-PAGE方法对RIL-7的Wx基因突变类型进行检测,发现在228个株系中,正常类型的株系有34个,Wx-A1突变体为26个,Wx-B1突变体为32个,Wx-D1突变体30个,Wx-A1和Wx-B1位点同时突变的有28个,Wx-A1和Wx-D1位点同时突变的有20个,Wx-B1和Wx-D1位点同时突变的为28个,3个Wx基因位点均突变的为16个。卡方测验证明,3个Wx基因位点的突变符合孟德尔遗传规律,属于质量性状遗传。田间试验表明,8种类型之间在初花期、株高和穗粒数上无显著差异,但在穗长、每穗小穗数和千粒重上Wx-A1突变型显著低于其他7种类型,而7种类型间无显著差异。淀粉特性研究表明,不同Wx蛋白缺失显著影响直链淀粉含量、淀粉糊化特性和淀粉凝胶的质构剖面分析 (TPA) 特性。正常类型的直链淀粉含量最高(20.8%),糯麦的最低(1.1%)。糯麦淀粉的峰值黏度和稀澥值较高,但其低谷黏度、最终黏度和反弹值较低,与其他缺失类型间差异达5%显著水平。凝胶的TPA测试表明,随着直链淀粉含量的降低,凝胶的硬度、黏着性、弹性、胶着性和咀嚼性显著降低,而黏聚性和回复性显著升高。直链淀粉含量与糊化特性的低谷黏度、最终黏度、反弹值、峰值时间和糊化温度之间正相关达1%显著水平(r=0.892~0.965),与峰值黏度、稀澥值呈1%水平负相关( r=-0.892, r=-0.945);直链淀粉含量与凝胶TPA参数的黏聚性、回复性呈极显著负相关(r=-0.928, r=-0.829),与凝胶的硬度、黏着性、弹性、胶着性和咀嚼性呈极显著正相关( r=0.869~0.979)。  相似文献   

13.
Amylose content is a major determinant of the eating quality in rice. To elucidate the allelic diversity at the Waxy (Wx) gene which controls the amylose synthesis, two cultivated strains having opaque endosperms were studied. The gene responsible for opaque endosperms was introduced into the genetic background of the Japonica type of rice by successive backcrosses, and the two near-isogenic lines (NILs) were selected from the B5 generation. The genetic experiments revealed that an allele, Wxop, controls opaque endosperms which show chalky as wx endosperms in spite of the production of amylose. Immunoblotting analysis was carried out to compare the gene expression by using the NILs with 4 different alleles (Wxa, Wxb, Wxop and wx). The level of the gene product bound to starch granules was slightly lower in the NILs with Wxop than that with Wxb, showing a positive correlation with amylose content in the endosperm. Extracts from mature anthers indicated that the gene product was markedly reduced in the NILs with Wxop as well as that with wx, showing an altered expression in the tissue specificity in the Wxop lines. Sequence analysis suggested that the Wxop had been derived from Wxa, independently of the origin of Wxb. The importance of the gene regulation was discussed in relation to diversified phenotypes established during the domestication process.  相似文献   

14.
To find out gene dose effect of each of the three homoeologous Wx genes and their interaction on the production of granule-bound starch synthase (GBSS I) and amylose biosynthesis in the endosperm, Chinese Spring and its near-isogenic waxy types were crossed reciprocally and, obtained a plant population with varying doses of each Wx gene. The amount of GBSSI was increased linearly with increasing gene dose of either of Wxloci. In each of the three Wx loci, the change in amylose content was linear up to 3 doses, with a more potent capacity ofWx-B1a at any dose. Higher level of amylose production was observed in the reciprocal F1 grains than the expected effect of dose/s of each gene or additive effect of different allelic combination by artificially blend starches which have amylose produced by equivalent number ofWx alleles to that of relevant F1 cross. When Wx-B1a and Wx-A1a were combined, increase in amylase content was not in proportion to increase in gene dosage. The enhanced amylase synthesis was shown by 2-gene and 3-geneinteraction, indicating that not only type of the three Wx genes and its dose but the interaction among them have significant roles in determining the amylose content. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

15.
谷子几种农艺性状基因染色体定位及连锁关系的初步研究   总被引:4,自引:0,他引:4  
利用三体分析法进行谷子染色体基因定位。以豫谷1号三体1-7、四体8和四体9为母本,显性矮秆、法谷56-81、马青苗为父本,配置组合分别进行显性矮秆基因、白米基因和青米基因染色体定位。根据三体1-7植株形态特征和父本标志性状鉴定各自的杂种F1,采用细胞学方法,通过检查植株根尖染色体数来鉴定杂种F1的三体8和三体9。经调查和分析各种三体杂种F2性状分离情况,把显性矮秆基因定位在3号染色体,白米基因定位在4号染色体,青米基因定位在6号染色体。对不同区域的9个青米品种等位检测表明,这些青米基因都是等位基因。以两点测验法,配置组合1066A×法谷56-81和1066A×马青苗进行基因连锁分析。结果,4号染色体上糯性胚乳基因与白米基因间的交换值为(28.9±4.4)cM;6号染色体上1066A不育基因与青米基因间的交换值为(23.2±1.8)cM。  相似文献   

16.
The waxy (Wx) gene encodes a granule-bound starch synthase (also called Wx protein) that is involved in synthesizing amylose in the starch grains of cereals, including common wheat (Triticum aestivum L.). Because amylose content affects the quality of food products made from wheat flour, Wx alleles affecting amylose content are of interest. Five wheat Wx alleles (Wx-A1c, -A1d, -A1e, -A1i and -A1j) that produce polymorphic Wx proteins on electrophoretic gels were investigated in terms of amylose content in starch and DNA sequences. Measurement and electrophoresis of gelled starch showed that apparent amylose contents of the genotypes were as follows: Wx-A1e, 2.9 % (= waxy phenotype) < -A1i, 8.0 % < -A1c, 16.8 % < -A1j, 22.6 % = level of wild type allele -A1a. DNA sequencing of the five alleles identified single nucleotide polymorphisms (SNPs) and insertion/deletion variations compared to Wx-A1a. A particular SNP causing amino acid changes in Wx-A1e and -A1c was identified as the factor responsible for decreased amylose. A SNP in Wx-A1d should cause an amino acid change and be responsible for an altered Wx-A1d protein. A transposable-like element of 376 bp present in the 3′ untranslated region (UTR) of Wx-A1i most likely lowered the levels of Wx protein and amylose through aberrant mRNA. The fifth allele, Wx-A1j, possessed four SNPs, two of which altered amino acids in the Wx-A1j protein and should cause polymorphism in the Wx protein. Based on the DNA sequences, functional markers for Wx-A1c, -A1d, -A1e and -A1i were developed.  相似文献   

17.
In order to identify quantitative trait loci (QTL) for the eating quality of waxy corn and sweet corn (Zea mays L.), QTL analysis was conducted on an F2 population derived from a cross between a waxy corn inbred line and a sweet corn inbred line. Ten QTLs for pericarp thickness (PER), amylose content (AMY), dextrose content (DEX) and sucrose content (SUC) were found in the 158 F2 families. Among them, four QTLs, qAMY4 (10.43%), qAMY9 (19.33%), qDEX4 (21.31%) and qSUC4 (30.71%), may be considered as major QTLs. Three of these, qAMY4, qDEX4 and qSUC4, were found to be located within a region flanked by two adjacent SSR markers on chromosome 4 (umc1088 and bnlg1265), making this SSR marker pair a useful selection tool for screening the eating quality traits of AMY, DEX and SUC. The QTL for amylose content was found to be located between markers phi027 and umc1634, raising the possibility of its identity being the Wx1 gene, which encodes a granule-bound amylose synthase. The new QTLs identified by the present study could serve as useful molecular markers for selecting important eating quality traits in subsequent waxy corn breeding studies.  相似文献   

18.
直链淀粉含量是影响稻米品质的最重要因素之一。为培育直链淀粉含量较低的软米和糯稻新品系,在经共转化法获得的转反义Wx基因水稻自交后代中筛选获得国不含抗性选择标记基因的纯合体.对这些纯合转基因水稻的分析表明,其未成熟种子胚乳中Wx基因表达水平和成熟种子中Wx蛋白量较未转化对照有不同程度的降低。转基因水稻成熟种子中直链淀粉含量较未转化对照有不同程度的下降,2个转基因系降低至10%左右,相当于软米的直链淀粉含量,1个转基因系降到了2%以下,形成了糯稻新品系。转基因稻米中直链淀粉含量降低后,其胶稠度相应变软,而糊化温度未发生明显改变。田间试验结果表明,转基因水稻的大部分农艺性状与受体品种武香粳9号无显著差异。因此,本研究成功培育了无抗性选择标记且淀粉品质改良的转反义Wx基因水稻新品系。  相似文献   

19.
The Wx-D1 protein (granule-bound starch synthase) of Kanto 107, Tanikei A6099 (low amylose line), and Tanikei A6599-4 (waxy line) has been analyzed by SDS-PAGE, peptide mapping and DNA sequencing. Kanto 107 and Tanikei A6099 have the same amino acid sequences in the mature protein, but amino acid substitution (alanine to threonine) occurs at position 258 in the mature protein in Tanikei A6599-4. A comparison of deduced amino acid sequences of the mature Wx-D1 protein in these lines indicates that point mutation in the Wx-D1 gene of Tanikei A6599-4 is responsible for its waxy character.This mutant waxy wheat does not show a reduction in amylose content identicalto other waxy wheats, which probably reduces activity of the GBSS I enzyme but does not to a complete loss of activity. We discuss the function of the mutant Wx-D1 protein in starch synthesis. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

20.
陈刚  刘巧泉  王忠  顾蕴洁  朱利佳 《作物学报》2005,31(9):1192-1197
以转反义Wx基因粳稻和籼稻为材料的研究结果表明,直链淀粉含量降低后的转基因水稻颖果的光合和呼吸活性在发育前期显著高于亲本,但下降较快,到了发育中期(花后15~18 d)以后,就低于同期的亲本。但其SOD和CAT活性比其亲本下降得慢,从花后9 d开始一直保持着比亲本高的水平。花后转基因水稻剑叶的叶绿素含量、光合速率和SOD  相似文献   

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