Prolamin subunit interactions in hexaploid and octaploid triticales and their wheat and rye parents

Biochemical characterization of lines descended from 8x triticale x 4x triticale cross

Fifty-two progenies originating from a cross between 8x and 4x triticale were submitted to cytogenetic analyses and to various electrophoretic studies [high-molecular-weight (HMW) glutelins, HMW secalins, γ-secalins, α and ω-gliadins, β-amylases] to identify new genetic structures, more specifically the input of the D genome in a genetic context other than the wheat one. Markers of the rye genome (HMW and ω-secalins) were identified in all of the triticale lines, but they originated either from the 4x or from the 8x parent, or from both. Chromosomes 4A, 1B, and 2R, present in both parents, showed the same banding patterns in all progenies. Chromosomes 1R and 5R, present in both parents, showed heterogeneous labelling. The expression of chromosomes 6A, 1D, and 4D, present in the 8x parent only, was more complex with a possible involvement of a regulatory system. Several hexaploid progenies had introgressed part of the D genome, suggesting that crossing 8x and 4x triticale was a practicable approach for transferring D chromosomes into hexaploid triticale.

Two-dimensional electrophoresis of cereal prolamins: applications to biochemical and genetic analyses

Three complementary two-dimensional systems for the analysis of cereal prolamins are described. These are electrophoresis at pH 3.1 followed by electrophoresis at pH 9.2, isoelectric focusing (IEF) followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and SDS-PAGE under non-reducing conditions followed by SDS-PAGE with reduction. They together give information on the pIs, Mrs and charge properties of the individual prolamin components, and on their interactions to form oligomers stabilized by inter-chain disulphide bonds. The three systems are then compared for their effectiveness in analysing unreduced prolamin I fractions from wheat and rye, and the IEF/SDS-PAGE system for analysing reduced and pyridylethylated prolamin fractions from all the major cereals. Finally, applications of the systems in biochemical and genetic studies are discussed and illustrated with three examples: analysis of the structural relationships of the S-rich prolamins (B hordeins and gamma-type hordeins) of barley, determination of the interactions of wheat and rye prolamin subunits in a 2RS/2BL translocation line, and the mapping of genes for alpha-type prolamins in the wild grass Haynaldia villosa.