Alteration of HMW glutenin subunits in wheat lines possessing new 1BL.1RS translocation

High molecular weight glutenin subunits are the main components of wheat storage proteins. We previously obtained a wheat line, Yw62-11, which possesses the 1BL.1RS translocation in backcross F₆ progenies of the hybrid of wheat Olmil and rye Paldanghomil. In an SDS-sedimentation test, BC ₁F₈ lines derived from Yw62-11 exhibited significantly elevated sedimentation volumes compared to the parent wheat Olmil. In an attempt to ascertain the cause of this disparity in sedimentation volume, we analyzed the endosperm proteins of the BC₁F₈ lines. SDS-PAGE revealed that the HMW glutenin subunits of the parent Olmil had been altered in the segregating lines. The subunits 2.2x + 12y at the Glu-1D locus in Olmil were transformed into subunits 5x + 10y in all BC₁F₈ lines, and the subunits 7x + 8y at the Glu-1B locus were segregated into 7x + 9y in some lines. In addition, some lines expressed subunit 1, which was silenced at the 1Ax gene in Olmil. These results constituted the first report that HMW glutenin subunits were altered in segregating wheat lines, even if the changes arose from the backcross of an intergeneric hybrid. Acid-PAGE showed that the secalin compositions of the new 1BL.1RS translocation lines could not be discriminated from the secalin compositions in 1RS of rye Petkus, the main source of 1RS in most contemporary wheat varieties.