山东省普通小麦醇溶蛋白Gli-1和Gli-2位点等位基因的遗传变异

采用酸性聚丙烯酰胺凝胶电泳(A-PAGE)，分析了山东省种植面积较大的37个小麦品种醇溶蛋白Gli-1和Gli-2位点等位基因的组成特点。结果表明，山东小麦在醇溶蛋白Gli-1 (Gli-A1、Gli-B1和Gli-D1) 和Gli-2 (Gli-A2、Gli-B2和Gli-D2) 位点存在多样性，共鉴定出58个等位基因，出现频率较高的有6个，分别为Gli-A1a (48.6 %)、Gli-B1l (35.1%)、Gli-D1k (35.1%)、Gli-A2b (35.1％)、Gli-B2g (35.1％)和Gli-D2a (29.7％)，其中Gli-B1l出现频率较高，表明1BL/1RS易位系在山东小麦中存在比较普遍。醇溶蛋白6个主要位点的遗传变异系数较高，平均为0.7930，变幅为0.7297～0.8269，其中Gli-D2位点遗传多样性最高，Gli-A1最低。对具有优质醇溶蛋白等位基因Gli-B1b或Gli-A2b的品种进行了高分子量谷蛋白亚基的组成分析,表明烟农15、烟优361、山农98-1和山农93-52同时含有优质谷蛋白5＋10亚基，在小麦育种中可利用这些优质亚基基因。     

小麦种子萌发过程贮藏蛋白变化及其与活力关系的研究

选用烟农19与郑麦9023为材料，采用A-PAGE和SDS—PAGE电泳方法，研究了新、陈小麦种子萌发过程贮藏蛋白质的变化及降解速度，结果表明，高活力种子醇溶蛋白变化明显，降解较快，低活力种子醇溶蛋白变化不大，且降解迟缓：高活力种子与低活力种子的谷蛋白降解速度变化均不明显。本研究认为，通过种子萌发过程中贮藏蛋白质电泳图谱分析，可以直观地判断小麦种子的活力水平，其中通过醇溶蛋白电泳图谱判断更好。     

Variation and genetic diversity for gliadins in Spanish spelt wheat accessions

Gliadin composition has been analysed in 403 accessions of spelt wheat (Triticum aestivum ssp. spelta); 61 different patterns were found for the -gliadins, 44 for the -gliadins, 19 for the -gliadins and 15 for the -gliadins. A subset of 333 accessions belonging to fifty populations from Asturias, North of Spain, showed high levels of genetic variation (A = 3.89, P = 0.88, Ne = 3.35 and He = 0.553), indicating that 82.5% of the genetic variation was within populations, and only 18.5% among populations. Thirty-five of these populations presented more of five accessions, in this new subset the values of genetic variation were higher that those of fifty populations (A = 4.49, P = 0.91, Ne = 3.80 and He = 0.595). The genetic variation within populations was 59.7% of the total, and 40.3% among populations, which could be associated to fixation effects of some alleles by genetic drift.     

Analysis of duplication in the Spanish durum wheat collection maintained in the CRF-INIA on the basis of agro-morphological traits and gliadin proteins

A total of 106 potential duplicate cases involved 277 accessions were detected on the basis of passport data in the durum wheat collection maintained in the CRF-INIA. Similarity between accessions was measured by agro-morphological traits. The 90% of the agro-morphological duplication were verified with gliadin proteins, allowing identification of similar material with greater refinement than agro-morphological data. However, the results indicated not to decide for rationalisation only on the basis of molecular data.     

Influence of allelic prolamin variation and localities on durum wheat quality

Thirty-seven varieties of a Mediterranean durum wheat collection grown in Tunisia and Spain were analysed for their allelic composition in prolamins, as well as their protein concentration, sodium dodecyl sulphate sedimentation (SDSS) test and mixograph parameters. Genotype was a greater source of variation in all measurements than locality. Uncommon high and low molecular glutenin subunits (HMW-GS and LMW-GS) were found (V and 2•• subunits at Glu-A1, 13 + 16 at Glu-B1, 5* subunit and ax allele at Glu-A3). The rare combinations 2 + 4+14 + 18 and 8 + 9+13 + 16+18 subunits at the Glu-B3 locus were found. Glu-A3ax had a positive influence on SDSS and mixograph parameters. Of all the prolamins, those that have the B-LMW-GS composition aaa (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d gave the best semolina quality. By contrast, semolina quality is poor when this same composition is associated with the Glu-A1c and Glu-B1e and even poorer when associated with the Glu-A1c and Glu-B1f. In addition, the cultivars with B-LMW-GS allelic composition aab (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d, gave high quality, whereas when associated with the Glu-A1c and Glu-B1e or with Glu-A1o and Glu-B1f, the quality was very poor.     

Effect of allelic variation at the Glu-3/Gli-1 loci on breadmaking quality parameters in hexaploid wheat (Triticum aestivum L.)

Low molecular weight glutenin subunits (LMW-GS) encoded by the Glu-3 loci are known to contribute to wheat breadmaking quality. However, the specific effect of individual Glu-3 alleles is not well understood due to their complex protein banding patterns in SDS-PAGE and tight linkage with gliadins at the Gli-1 locus. Using DNA markers and a backcross program, we developed a set of nine near isogenic lines (NILs) including different Glu-A3/Gli-A1 or Glu-B3/Gli-B1 alleles in the genetic background of the Argentine variety ProINTA Imperial. The nine NILs and the control were evaluated in three different field trials in Argentina. Significant genotype-by-environment interactions were detected for most quality parameters indicating that the effects of the Glu-3/Gli-1 alleles are modulated by environmental differences. None of the NILs showed differences in total flour protein content, but relative changes in the abundance of particular classes of proteins cannot be ruled out. On average, the Glu-A3f, Glu-B3b, Glu-B3g and Glu-B3i_Man alleles were associated with the highest values in gluten strength-related parameters, while Glu-A3e, Glu-B3a and Glu-B3i_Chu were consistently associated with weak gluten and low quality values. The value of different Glu-3/Gli-1 allele combinations to improve breadmaking quality is discussed.     

Characterization of two 1D-encoded ω-gliadin subunits closely related to dough strength and pan bread-making quality in common wheat (Triticum aestivum L.)

Gliadin proteins of 113 common or bread wheat (Triticum aestivum L.) cultivars and advanced lines from China and other countries, were analyzed by high performance capillary electrophoresis (HPCE) and reversed-phase high performance liquid chromatography (RP-HPLC). A major protein peak migrating at 3 min by HPCE and eluting at about 20 min by RP-HPLC was identified in the ω-gliadin region. It was present in cultivars with good pan bread-making quality, whereas most cultivars with poor bread-making quality lacked this protein peak. Quality testing and statistical analysis showed that this ω-gliadin peak was significantly related to dough strength, loaf volume and loaf score. It was separated into two apparent protein components by one-dimensional SDS-PAGE and two-dimensional electrophoresis (2-DE). According to their relative mobilities on the gels, the proteins were designated ω-15 and ω-16, and their accurate molecular masses (42590.5 Da for ω-15 and 41684.1 Da for ω-16) were determined by MALDI-TOF-MS. The ω-15 and ω-16 gliadins possessed the N-terminal amino acid sequences of ARELNPSNKELQQQQ and KELQSPQQQF, and therefore they belonged to 1D-encoded ω-2 type and ω-1 type gliadins, respectively. Both gliadin subunits were always present together among the 86 cultivars analyzed, suggesting that they were encoded by two closely linked genes at Gli-D1 locus. The accumulative characteristics of gliadins during grain development indicated possible additive quantitative effects of ω-15+16 on dough strength. The ω-15 and ω-16 gliadins could be used as valuable genetic markers for wheat quality improvement.     

小麦-冰草异附加系种子醇溶蛋白基因表达的分析

本文通过对两个系列14个小麦-冰草（Triticum aestivum-Agropyron intermedium)异附加系种子醇溶蛋白的SDS电泳分析，探讨了异源的天蓝冰草染色体在小麦基因组背景下的表达及其对小麦基因表达的影响。结果表明，附加不同的冰草染色体能以不同的方式影响小麦种子醇溶蛋白基因的表达。在个别异附加系中，冰草染色体上的醇溶蛋白     

Silencing of γ-gliadins by RNA interference (RNAi) in bread wheat

RNA silencing is a sequence-specific RNA degradation system that is conserved in a wide range of organisms. The elucidation of the mechanism of RNA silencing has stimulated its use as a reverse genetics tool, because RNA silencing strongly down-regulates the expression of the target gene in a sequence-specific manner. The major protein fraction of wheat grain is gluten which is largely responsible for the functional properties of dough. Gliadins contribute mainly to the extensibility and viscosity of gluten and dough, with the polymeric glutenins being responsible for elasticity. The aim of this work was therefore to silence the expression of specific γ-gliadins by RNA interference, to demonstrate the feasibility of systematically silencing specific groups of gluten proteins. The sequence of a γ-gliadin gene was used to construct the pghp8.1 plasmid. The hpRNA silencing fragment was designed on the basis of 169 base pairs (bp) in sense and antisense orientation with the sequence of the Ubi1 intron as spacer region between the repeats. Two lines of bread wheat were transformed by particle bombardment. Gliadins were extracted from 30 mg of flour, separated by acid-PAGE and determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Seven transgenic lines were obtained and all of them showed reduced levels of γ-gliadins. All seven transgenic plants were fully fertile and their grain morphology and seed weight were comparable to the control lines. MALDI-TOF MS showed that six peaks, present in the untransformed line, were missing in transgenic lines of the BW208 genotype whereas three peaks were missing in the BW2003 genotypes. The proportion of γ-gliadins was reduced, by about 55–80% in the BW208 lines and by about 33–43% in the BW2003 lines. The ELISA assay based on the R5 antibody showed reductions in total gliadins (μg/mg flour) in three of the BW208 lines and in one BW2003 line, but an increase in one BW208 line (C613).     

Wheat artificial amphiploids involving the <Emphasis Type="Italic">Triticum timopheevii</Emphasis> genome: their studies,preservation and reproduction

The effective utilisation of available genetic resources of related species is essential for successful crops breeding and maintaining genetic variability within crops. Bread wheat, the basic cultivated wheat species, is an amphiploid (2n = 6x = 42) and, therefore, the production of new synthetic amphiploids using genomes of related species should reduce the difficulties caused by direct crossings, for example, between hexaploid wheat and diploid relatives. Hence, exploiting synthetic amphiploids is an effective and rapid way of introgressing desirable traits from related species into cultivated wheats. Some of the artificial amphiploids that already exist were produced 80 years ago. Yet little work has been done to highlight potential contamination and/or genetic changes during their conservation by genebanks. Thus, we utilised the electrophoresis of wheat endosperm storage proteins (gliadins) to check such amphiploid authenticity, and also where differences had been previously observed between synthetic wheat amphiploids. In addition, we checked putative amphiploid accessions where Triticum timopheevii (GGA^tA^t) was recorded as one of the parents. A synthetic species, T. timococcum produced by Kostov, together with a natural T. zhukovskyi found in Georgia (the former Soviet Union) were revealed to be identical according to our assays. The existence of several T. kiharae accessions independently produced by different authors was confirmed, and they exhibited polymorphism for a number of traits, including spike characters (awning, hairy glumes) and growth habit (spring vs. winter). The effective conservation of artificial amphiploids in genebanks is discussed.