Isolation and molecular characterization of two novel HMW-GS genes from Chinese wheat (Triticum aestivum L.) landrace Banjiemang

Abstract

High molecular weight glutenin subunits (HMW-GS) play a significant role in determining bread-making qualities of common wheat flour. The study presented in the paper identified two novel HMW-GS (designated as 1Bx14* and 1By15*) at the Glu-B1 locus in Chinese wheat (Triticum aestivum L.) landrace Banjiemang by SDS-PAGE. The open reading frames (ORFs) of the genes were amplified and cloned with designed specific primers. Both of them had sequences highly similar to those of other HMW-GS genes, but displayed minor modification. The ORF of 1Bx14* was 2367 bp long and encoded 789 aa with 4 cysteines, which included 25 nanopeptides, 65 hexapeptides and 7 tripeptides motifs. The ORF of 1By15* was 2106 bp long and encoded 702 aa with 7 cysteines, which included 23 nanopeptides and 53 hexapeptides motifs. The predicted molecular weights of the mature proteins encoded by 1Bx14* and 1By15* genes were 83.1 and 73.2 k Da, respectively. The presence and authenticity of the two genes in Banjiemang were confirmed by bacterial expression and liquid chromatography-electrospray ionization mass spectrometry (LC–ESI–MS). By phylogenetic analysis, the 1Bx14* was clustered with x-type subunits but had a high divergence with other 1Bx subunits, whereas the 1By15* was clustered with y-type subunits and closely related to subunit 1By15. The study concluded that 1Bx14* and 1By15* from Banjiemang were novel allelic variations of HMW-GS at Glu-B1 locus, which were probably exploitable as new resources for wheat quality improvement.