Allelic variation of the HMW glutenin subunits in Aegilops tauschii accessions detected by sodium dodecyl sulphate (SDS-PAGE), acid polyacrylamide gel (A-PAGE) and capillary electrophoresis

Variability of high molecular weight glutenin subunits (HMW-GS) was studied in198 accessions of Ae. Tauschii (2n=2x=14, DD) by sodium dodecyl sulphate(SDS-PAGE) and acid polyacrylamide gel electrophoresis (A-PAGE) and capillary electrophoresis (CE). A high allelic variation of HMW-GS, including some novel x- and y-type subunits and variable subunit combinations were observed. One accession(TD159) showed a x-type null form. The results by A-PAGE analysis revealed that the subunits Dx5 ^t and Dy10 ^t encoded by Glu-D ^t 1 locus in Ae. tauschii were different in relative mobilities in comparison with the subunits Dx5 and Dy10 found in bread wheats, whereas they had the same mobilities, respectively, when separated by SDS-PAGE. The higher resolution of Ae. tauschii HMW-GS separated by CE method showed two clear peaks in accordance with x- and y-type subunits, respectively,except the accession TD151 which possessed only subunit Dy12.1^*t. The electro elution time of the x-type and y-type subunits were about 13–14 and 7–8minutes, respectively. Characterization of wheat HMW-GS was facilitated by using CE which provides high resolution and increases the speed of analysis in conjunction with the traditional gel electrophoretic methods. A total of 42HMW-GS alleles were identified, among which were several alleles not presently detected in bread wheats. Hence Ae. tauschii is potentially a valuable genetic resource for quality improvement of bread wheat. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genetic mapping of the Acph1 locus in Aegilops tauschii

The Acph1 locus of Aegilops tauschii encodes a new electrophoretically ‘fast’ acid phosphatase, whose allelic variation could well be involved in intraspecies differentiation. Genetic mapping via microsatellite (simple sequence repeat) analysis revealed that Acph1 is tightly linked with the marker Xgwm157 near the centromere region of chromosome 2.     

Identification and isolation of a new x-type HMW glutenin subunit 1Dx1.6t gene from Aegilops tauschii

A new x-type HMW glutenin subunit, designated as 1Dx1.6^t from Aegilops tauschii was identified and characterized by SDS-PAGE and MALDI-TOF-MS. This subunit is located between 1Dx2 and 1Dx1.5^t and possesses a molecular mass ( M _r) of 88565.8 Da. Its complete coding sequence was amplified via allele-specific PCR (AS-PCR), and the amplified product was cloned and sequenced. The authenticity of the cloned 1Dx1.6 ^t gene was confirmed by successful expression of its open reading frame in Escherichia coli. The molecular characterization of 1Dx1.6 ^t gene showed that its coding region consisted of 2541 bp encoding a polypeptide of 845 amino acid residues. Sequence comparison to previously characterized 1Dx1.5^t subunit which is related to good dough quality of bread wheat indicated that the 1Dx1.6^t subunit displayed high homology, but possesses 14 residue substitutions and a nonapeptide insertion. A total of 12 single-nucleotide polymorphisms (1 per 212 bp) was identified in the 1Dx1.6 ^t allele (11 in repetitive domain and 1 in the C-terminal domain), which could facilitate the design of AS-PCR markers.     

Gli-D t T1 and a novel γ-gliadin gene in Aegilops tauschii

Genetic studies of F₂ progeny from a cross between Aegilops tauschii accessions AUS18913 and CPI110856 revealed that Gli‐D^tT1 is tightly linked with a γ‐gliadin gene at the Gli‐D^t7 locus located on the short arm of chromosome 1D. Acid‐polyacrylamide gel electrophoresis (A‐PAGE) used to examine the gliadins of this population revealed two genes that encode a ω‐gliadin (T₁) protein and a novel γ‐gliadin protein. The ω‐gliadin (T₁) protein and the novel γ‐gliadin protein cosegregated, while having 0.69 cM recombination with the other locus (Gli‐D^t1). N‐terminal sequences were used to further classify the proteins studied.     

A proposed method of polyacrylamide gel electrophoresis in acid environments applied to gliadins of wheat grains

Summary In this paper we describe the method of wheat gliadin electrophoresis in use at RIVRO, Wageningen. It differs from other techniques mainly by the application of an alternative buffer system, making it possible to polymerise the gels in a buffered alkaline environment and to perform the run at pH 3.1 without extensive buffer changing steps. Advantages are a greater gel reproducibility and the ease of gel handling. Furthermore, a rationalised protein extraction procedure, a cheap shaking system for staining baths and a better (slower moving) tracking dye are described.     

抗条锈、抗穗发芽六倍体人工合成小麦Cereta/Aegilops tauschii783的SSR标记分析

Cereta/Aegilops tauschii783是由CIMMYT引进的硬粒小麦/节节麦人工合成种,具有高抗条锈和高抗穗发芽等优良特性.本文选用小麦A、B、D染色体组的91对SSR引物将人工合成小麦Cereta/Aegilops tauschii783与绵阳26在分子水平上进行了比较分析,结果表明：91对引物中有88对引物能扩增出清晰条带;88对引物中除3对引物外,86对引物（96.59%）均能揭示出Cereta/Aegilops tauschii783与绵阳26之间的差异.人工合成小麦Cereta/Aegilops tauschii783与育成小麦品种遗传差异很大,是丰富现代小麦遗传多样性的优异基因源;利用人工合成小麦Cereta/Aegilops tauschii783与绵阳26构建SSR标记群体,可有效标记双亲优良基因.     

Characterisation of European oat germ plasm: allelic variation at complex avenin loci detected by acid polyacrylamide gel electrophoresis

European oat germ plasm involving 252 varieties, landraces, and breeding lines has been characterised by allelic constitution at three independent complex avenin loci. A total of 26 avenin alleles (blocks), including 7 at the Ave1 (Avn A), 10 at the Ave2 (Avn B), and 9 at the Ave3 (Avn C) loci were revealed. The avenin block variants were shown to be coded by gene clusters of 2–5 single expressed genes. A catalogue of the identified avenin blocks as well as a list of the avenin phenotypes is presented. It has been discovered that about 8% of the oat varieties were heterogeneous comprising two or three different avenin profiles. The varieties assayed have been classified into 79 avenin phenotypes made up by the different alleles. Forty-six of these phenotypes were distinguished uniquely, while the other 33 were shared by groups possessing from 2 to 41 genotypes each. Members within these groups had certain ancestors in common. Non-random patterns of both the avenin allele and phenotype distributions have been found. This revised version was published online in July 2006 with corrections to the Cover Date.     

Origin of Sv Genome of Aegilops variabilis and Utilization of the Sv as Analyser of the S Genome of the Aegilops Species in the Sitopsis Section

Hybrids of Aegilops variabilis (2n = 28, UUS^vS^v) with the low-pairing type lines of Ae. longissima, Ae. bicornis, Ae. searsii, Ae. speltoides and Ae. umbellulata were obtained. This is the first report of successful hybridization between Ae. variabilis and Ae. searsii. Meiotic analysis of these hybrids showed that the U genome of Ae. variabilis donated by Ae. umbelltilata remained nearly unchanged and Ae. longissima is the possible donor species of the S genome to Ae. variabilis. But the S^v genome and the S¹ genome of Ae. longissima are not completely homologous and are structurally differentiated by at least one interchange. According to their levels of homology with S^v through the means of chromosome associations, the four genomes of Sitopsis section species can be classified as follow: S^v? S¹ > S^b > S^s > S. The meiotic behaviour of the hybrids between the wheat ‘Chinese Spring’ and the four Sitopsis section species studied has not supported the view that one of the four species is the donor of the B genome of wheat.     

Genetic diversity of European spelt wheat (Triticum aestivum ssp. spelta L. em. Thell.) revealed by glutenin subunit variations at the Glu-1 and Glu-3 loci

Summary High and low molecular weight glutenin subunit (HMW-GS and LMW-GS) compositions of 270 European spelts, 15 Iranian spelts and 25 bread wheat cultivars were analyzed by one- and two-dimensional gel electrophoresis. The results revealed a total of 22 HMW-GS alleles (4 at Glu-A1, 11 at Glu-B1 and 7 at Glu-D1) and 32 allele combinations among the three Glu-1 loci. Two major genotypes of HMW-GS: 1, 13+16, 2+12 and 1, 6.1+22.1, 2+12 were found to occur in Central European spelt wheat cultivars and landraces at higher frequencies of 35 and 28%, respectively. The Glu-B1 locus displayed the greatest variation and genetic diversity index (H) was 0.69 whereas Glu-A1 and Glu-D1 showed H index values of 0.26 and 0.19, respectively. The dendrogram constructed by HMW and LMW glutenin subunit bands revealed that European spelts form a separated cluster from common wheat suggesting that spelt and common wheat form distinct groups. In addition, all 15 Iranian spelt land variety accessions differed from European spelts and possessed similar HMW-GS alleles to common wheat. Because of a wider polymorphism Central European spelt wheats are an important genetic reserviour for improving common wheat quality. Both authors contributed equally to this work