Molecular characterization of two y-type high molecular weight glutenin subunit alleles 1Ay12⁎ and 1Ay8⁎ from cultivated einkorn wheat (Triticum monococcum ssp. monococcum)

Abstract

Two y-type high molecular weight glutenin subunits (HMW-GSs) 1Ay12⁎ and 1Ay8⁎ from the two accessions PI560720 and PI345186 of cultivated einkorn wheat (Triticum monococcum ssp. monococcum, AA, 2n=2x=14), were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The mobility of 1Ay12⁎ and 1Ay8⁎ was similar to that of 1Dy12 and 1By8 from common wheat Chinese Spring, respectively. Their ORFs respectively consisted of 1812bp and 1935bp, encoding 602 and 643 amino acid residues with the four typical structural domains of HMW-GS including signal peptide, conserved N-, and C-terminal and central repetitive domains. Compared with the most similar active 1Ay alleles previous published, there were a total of 15 SNPs and 2 InDels in them. Their encoding functions were confirmed by successful heterogeneous expression. The two novel 1Ay alleles were named as 1Ay12⁎ and 1Ay8⁎ with the accession No. JQ318694 and JQ318695 in GenBank, respectively. The two alleles were classed into the two distinct groups, Phe-type and Cys-type, which might be relevant to the differentiation of Glu-A1-2 alleles. Of which, 1Ay8⁎ belonged to Cys-type group, and its protein possessed an additional conserved cysteine residue in central repetitive region besides the six common ones in N- and C-terminal regions of Phe-type group, and was the second longest in all the known active 1Ay alleles. These results suggested that the subunit 1Ay8⁎ of cultivated einkorn wheat accession PI345186 might have a potential ability to strengthen the gluten polymer interactions and be a valuable genetic resource for wheat quality improvement.