Cloning and characterization of low-molecular-weight glutenin subunit alleles from Chinese wheat landraces (Triticum aestivum L.).

Hongqi Si,Genlou Sun,Xin Zhang,Manli Zhao,Guoliang Yao,Chuanxi Ma

doi:10.1155/2014/371045

Abstract

Low-molecular-weight glutenin subunits (LMW-GS) are of great importance in processing quality and participate in the formation of polymers in wheat. In this study, eight new LMW-GS alleles were isolated from Chinese wheat landraces (Triticum aestivum L.) and designated as Glu-A3-1a, Glu-A3-1b, Glu-B3-1a, Glu-B3-1b, Glu-B3-1c, Glu-D3-1a, Glu-D3-1b, and Glu-D3-1c, which were located at the Glu-A3, Glu-B3, and Glu-D3 loci, respectively. Based on the proteins encoded, the number of deduced amino acids of Glu-B3 alleles was approximately 50 more than those of Glu-A3 and Glu-D3 alleles. The first cysteine of Glu-A3 and Glu-D3 alleles was located at the N-terminal domain, while that of Glu-B3 alleles was found in the repetitive domain, which may lead to the different functioning in forming disulfide bonds. All the eight genes were LMW-m types and the new allele of Glu-B3-1a which had nine cysteine residues may be the desirable LMW-GS gene for improving bread-making quality.

Highlights

Wheat dough possesses unique viscoelastic properties determined by the structure and interaction of storage proteins in making bread and noodles [1]
Wheat storage proteins are mainly composed of monomeric gliadins and polymeric glutenins [2, 3], and these glutenins are divided into the low-molecular-weight glutenin subunits (LMW-GS) and the high-molecular-weight glutenin subunits (HMWGS) according to their electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDSPAGE) [4]
The LMW-GS genes are encoded by Glu-A3, Glu-B3, and Glu-D3 loci on the short arms of chromosomes 1A, 1B, and 1D, respectively, in hexaploid wheat [7]

Summary

Introduction

Wheat dough possesses unique viscoelastic properties determined by the structure and interaction of storage proteins in making bread and noodles [1]. Allelic variation in LMW-GS is generally accepted to have an important effect on wheat processing quality [8]. The effects of Glu-A3d, Glu-B3i, Glu-A3d, and Glu-B3d contribute most to dough extensibility and Zeleny sedimentation volume, while Glu-D3 loci do not have a significant effect on either [9]. According to He et al [10], noodle quality is decided by the protein subunits of Glu-A3d and Glu-B3d, and Glu-A3d is significantly more important in this process than other alleles. We isolated and characterized eight new alleles located at Glu-A3, GluB3, and Glu-D3 loci from landraces for which no LMW-GS genes have been previously detected by the corresponding molecular markers [17,18,19]

Materials and Methods

Results and Discussion

Conclusion

Conflict of Interests