Characterization of novel high-molecular-weight glutenin subunits and their coding sequences in Aegilops markgrafii

Wheat's wild relatives are potential resources for the genetic improvement of common wheat quality. Novel high-molecular-weight glutenin subunits (HMW-GS) from Aegilops markgrafii were identified using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Three complete coding sequences of novel HMW-GS were cloned and sequenced. The lengths of these sequences, encoding 881, 847, and 644 amino acid residues, were 2649, 2571, and 1938 bp (designated as Cx1, Cx3, and Cy3), respectively. Sequence comparison showed that added SNPs and InDels were responsible for major variations in the new genes. Analysis of the deduced amino acid sequences revealed that the primary structures of the x- and y-type HMW-GS of Ae. markgrafii were similar to those of previously published HMW-GS. In particular, all new Cx subunits had higher molecular weights than the previously reported HMW-GS in Ae. markgrafii, which have potential value in improving bread quality. Phylogenetic analysis supported the information on the origin of the B genome in wheat. In conclusion, our study not only broadens our understanding of the genetics and phylogenetic knowledge of the HMW-GS protein family but also provides new insight into wheat breeding for end-use quality improvement.