Polymorphism of High Mr Glutenin Subunits in Triticum tauschii: characterisation by chromatography and electrophoretic methods

A large collection of accessions of the wild wheat progenitor Triticum tauschii, the donor of the D genome of Triticum aestivum, was evaluated for the variability of high molecular weight (Mr) glutenin subunits by electrophoretic and chromatographic methods. A large range of allelic variation at the Glu-Dt1 locus was found in this collection and some novel subunits were observed in both x- and y-type glutenin subunits, including x- or y-type null forms. A few accessions showed three bands in the high Mr glutenin subunit region. However, only two subunits were observed when monomeric proteins were removed before SDS-PAGE analysis of polymeric proteins. The presence of monomeric proteins in this region is discussed. Characterisation of these subunits was also carried out by reversed phase-high performance liquid chromatography (RP-HPLC). Very different surface hydrophobicities were observed between x- and y-type subunits and in some cases it was possible to identify glutenin subunits with the same apparent molecular weight but different surface hydrophobicity. Differences in elution times that were detected when the same subunit was either reduced or reduced and alkylated were related to the number of cysteine residues present in each glutenin subunit. The new Glu-Dt1 glutenin subunits have the potential to enhance the genetic variability available for improving the quality of bread wheat (T. aestivum).