Interfacial Behaviour of Secalin and Rye Flour-milling Streams in Comparison with Gliadin

Secalin was extracted from rye flour and analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The SDS-gel pattern showed that some proteins were composed of disulphide linked polypeptide chains. However, a gliadin sample contained more polymeric protein. The behaviour of gliadin and secalin at the air–water interface was compared using the surface balance technique. It was found that secalin was more surface active than gliadin, spreading faster and to a higher surface pressure. The influence of pH on the interfacial behaviour was also studied. The surface pressure after 45 min equilibrium of both gliadin and secalin decreased with decreasing pH. The effect was independent of the acid (hydrochloric acid, lactic acid or ascorbic acid) when compared at the same pH. The behaviour at the gas–liquid interface of five different rye flour-milling streams together with the whole (straight run) flour was also investigated. The fraction with highest protein content spread fastest and reached the highest surface pressure value. When spread on ascorbic acid at pH 3·7 the surface pressure of the flour stream with lowest protein content decreased to the greatest extent, whereas the fraction with the highest protein content was not affected. It was thus found that, although secalin showed an interfacial behaviour similar to gliadin, this behaviour was not necessarily shown by the total protein mixture in a rye flour.     

黑麦属贮藏蛋白的SDS-PAGE分析

对72份黑麦属材料的贮藏蛋白进行了SDS-PAGE分析。结果表明,黑麦属贮藏蛋白与普通小麦不同,可明显区分为4种组分:HMW、-γ75k、ω和-γ40k。黑麦属72份材料共有54种贮藏蛋白带型,每个材料可分离出7~11条带,多数为9~10条。在HMW区检测到6种亚基,22种不同组合。-γ40k区多为3条带,其他区域均以2条带最为普遍。各区域均可反映一定程度的变异,但以HMW-GS和-γ45区变异最大,揭示的材料间的遗传相似系数(GS)分别为0.622和0.776。72份材料平均GS值为0.748,变幅为0.450~1.000。森林黑麦(S.sylvestre)种内的GS值最高,达0.970,而普通黑麦(S.cereale)种内的GS值最低,为0.797。森林黑麦与普通黑麦的种间GS值最低,为0.633,与其他2个种的种间GS值也均较低(<0.700)。瓦维洛夫黑麦(S.vavilovii)与森林黑麦(S.cereale)的种间GS值高达0.785。该结果说明,SDS-PAGE可以有效地揭示黑麦属贮藏蛋白丰富的遗传差异,并可在一定程度上反映黑麦属种间的亲缘关系。     

The quantitative relationship between telomeric heterochromatin and secalin synthesis in Secale cereale L.

Summary The relationship between the amount of prolamine (secalin) synthesized and the amount of telomeric heterochromatin in ten inbred lines of rye (Secale cereale L.) cv. Self Fertile Spring was investigated. There was no association between the total amount of secalin synthesized and the amount of telomeric heterochromatin per haploid genome. However, a positive relationship was found between total secalin synthesis and the amount of telomeric heterochromatin on the short arm of chromosome 7 (7RS). Lines synthesizing high levels of secalin were found to have approximately 60% less telomeric heterochromatin on chromosome arm 7RS than lines synthesizing low levels of secalin. There was no positive relationship between secalin synthesis and the amount of telomeric heterochromatin present on any other telomere.     

Development and application of a new codominant PCR marker for detecting 1BL·1RS wheat–rye chromosome translocations

The 1BL·1RS translocation has been widely used in wheat breeding programmes throughout the world. Unfortunately, this translocation has frequently resulted in unsatisfactory grain processing quality. Two primer combinations derived from the published sequence of a ω‐secalin gene on 1RS gave polymerase chain reaction (PCR) fragments 0.4 and 1.1 kb in size. Both fragments can be used to quickly detect 1BL·1RS translocations. By combining the PCR assay resulting in the 1.1‐kb fragment from 1RS and a PCR assay resulting in a 0.6‐kb fragment from the Glu‐B3 gene on 1BS, plants homozygous for the 1BL 1RS could clearly be distinguished from the heterozygous ones. This codominant marker was successfully applied to genotype a segregating F₂ population and a local cultivar collection.     

Mapping of powdery mildew and leaf rust resistance genes on the wheat-rye translocated chromosome T1BL·1RS using molecular and biochemical markers

Powdery mildew and leaf rust resistance genes on the 1RS arm of the T1BL·1RS translocated chromosome were mapped in relation to the Sec‐1 locus and AFLP and restriction fragment length polymorphism markers, respectively, employing segregating F₃ populations. Integration of molecular markers indicated that Pm17 lies between the Lr26 and Sec‐1 loci, with both resistance genes allocated distally to the Sec‐1 locus in the satellite of the 1RS arm.     

Identification of Rye Chromosome 1R Translocations and Substitutions in Hexaploid Wheats Using Storage Proteins as Genetic Markers

Grain protein compositions of 106 advanced generation backcross lines from crosses involving ‘Amigo’ (1AL.1RS), ‘Aurora’, ‘Kavkaz’, ‘Skorospelka-35’ and ‘Sunbird’ (all 1BL.1RS) and ‘Gabo’ 1DL.1RS parents and 152 cultivars with unknown pedigree were analysed by one-dimensional SDS-PAGE. Eighty seven backcross lines and 16 cultivars carried one or other of these translocations, 2 cultivars had a 1R (1B) substitution, whereas 5 backcross lines were found to be heterogeneous for the 1BL.1RS translocation. The translocation lines were easily identified by the presence of secalins (Sec-1) controlled by rye chromosome arm IRS and a simultaneous loss of the gliadin (Gli-1) and/or triticin (Tri-1) protein bands controlled by the replaced wheat chromosome arm (1AS, 1BS or 1DS). Certain gliadins, showing no allelic variation among the genotypes analysed, were identified as markers for chromosome arms 1AS (M_r= 34 kd) and IBS (M_r= 42,33 kd). The whole chromosome substitutions 1R (1B) were recognized by scoring for the presence of Sec-1 and HMW secalin bands, Sec-3 (controlled by rye chromosome arm 1RL) and the absence of Gli-B1 and HMW glutenin subunits, Glu-B1 (controlled by wheat chromosome arm 1BL). The results have shown that protein electrophoresis provides a rapid and reliable technique for screening genotypes for these translocations and substitutions in a breeding programme.     

Genetic mapping of sequence-specific PCR-based markers on the short arm of the 1BL.1RS wheat-rye translocation

Wheat cultivars carrying the 1BL.1RStranslocation were crossed with newly synthesised octoploid triticale lines involving four rye genotypes having ο-secalin banding patterns different from each other and from that of the 1BL.1RS translocation. Homologous recombination was expected between the short arm of the 1R chromosomes of the rye genotypes and the 1RS arm of the 1BL.1RSwheat/rye translocation. Seven sequence-specific PCR-based markers:Xiag95, RMS13, Bmac0213, GPI, Xpsr960, 5Sand SCM9, and ο-secalinproteins were used to detect recombination events in the BC₁F₂ generation. Segregation analysis demonstrated that a barley SSR marker (Bmac0213) locus was present on the 1RS chromosome arm. Of 834plants tested in four different BC₁F₂ populations, 246individuals were found to carry recombined1BL.1RS translocation chromosomes. Genetic linkage analysis was performed on the eight markers in the four different mapping populations. The physical positions of the markers are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

The S-poor prolamins of wheat,barley and rye: Revisited

The last review of the S-poor prolamins was published in 1995. Since then there has been a considerable increase in out knowledge of this interesting and unique group of proteins. The advances in the understanding of genetics and polymorphisms of the proteins are discussed including the available gene sequences and their alignments and consensus sequences. This group of prolamins are implicated as major allergens in WDEIA and wheat allergy and as immunodominant proteins in coeliac disease. The epitopes and their distribution throughout the protein sequences are reviewed. Their structure and physical chemistry is discussed in relation to their functional properties.