Molecular characterization and marker development of a novel soft wheat high‐molecular‐weight glutenin subunit 1Dy12 ₁ for improving cookie‐baking quality

BACKGROUND High‐molecular‐weight glutenin subunits (HMW‐GSs) are the major determinants of gluten strength and dough elasticity, as well as wheat end use quality. A novel HMW‐GS 1Dy12 1 in soft wheat is associated with low protein content, weak gluten and superior cookie‐baking quality, but lacks a simple and effective genetic marker to distinguish it from other 1Dy alleles. RESULTS The subunit 1Dy12 1 allele was cloned for the first time from eastern USA soft winter wheat. Molecular characterization of the 1Dy12 1 subunit showed a coding nucleotide sequence of 2022 bp, which is 39 bp longer than the 1Dy12 subunit. The 1Dy12 1 subunit spanned 673 amino acid residues with a similar molecular structure to other published y‐type subunits at the Glu‐D1 locus. Known y‐type subunits at the Glu‐D1 locus have seven cysteine residues at conserved positions in the repetitive domain. Subunit 1Dy12 1 had an extra cysteine residue in the repetitive domain as a result of an adenine to guanine transition. A kompetitive allele‐specific polymerase chain reaction (KASP) marker for identifying the 1Dy12 1 allele was developed and validated using 32 eastern soft winter wheat varieties with either the 1Dy12 or 1Dy12 1 allele. The new KASP marker effectively distinguished varieties with subunit 1Dy12 1 from subunit 1Dy12. The marker also distinguished nine varieties with subunit 1Dy10 better suited to bread baking at the Glu‐D locus from subunit 1Dy12 1 varieties. CONCLUSION The new KASP marker is an effective tool to efficiently identify soft wheat varieties or breeding lines carrying HMW‐GS 1Dy12 1 for superior cookie‐baking quality.