Molecular characterization and phylogenetic analysis of active y-type high molecular weight glutenin subunit genes at Glu-A1 locus in wheat

An increased number of high molecular weight glutenin subunits (HMW-GSs) is advantageous to the formation of glutenin macropolymer, the major determinant of end-product quality. Out of the six HMW-GS genes, Glu-1Ay is typically inactive in most hexaploid wheat cultivars. In the current study, we characterized two active Glu-1Ay genes Glu-1AyN11 and Glu-1AyC422 from a hexaploid wheat cultivar N11 and a durum wheat cultivar C422, respectively. The molecular masses of the 1Ay subunit of N11 (Glu-1AyN11) and C422 (Glu-1AyC422) were 61.1 kDa and 63.9 kDa, respectively, measured by matrix-assisted laser desorption/ionization time of flight mass spectrometry. Molecular characterization of Glu-1AyN11 and Glu-1AyC422 showed their complete coding regions were 1764 bp and 1827 bp in length, respectively. The deduced amino acid sequence of both Glu-1AyN11 and Glu-1AyC422 has a similar typical primary structure as the other y-type HMW-GSs, but in comparison to Glu-1By and Glu-1Dy subunits, the Glu-1Ay subunit has one less conserved cysteine residue in the repetitive domain. Phylogenetic analysis revealed that the inactive Glu-1Ay had a closer evolutionary relationship with Glu-1AyC422 than with Glu-1AyN11. The divergence time among Glu-1AyN11, Glu-1AyC422, and other y-type subunit genes was also estimated.