Low molecular weight glutenin subunit gene Glu-B3h confers superior dough strength and breadmaking quality in wheat (Triticum aestivum L.).

Yaping Wang,Caixia Han,Xiaohui Li,Shoumin Zhen,Xiaobing Lu,Yueming Yan,Xianchun Xia,Zhonghu He,Nana Luo

doi:10.1038/srep27182

Abstract

Low molecular weight glutenin subunit is one of the important quality elements in wheat (Triticum aestivum L.). Although considerable allelic variation has been identified, the functional properties of individual alleles at Glu-3 loci are less studied. In this work, we performed the first comprehensive study on the molecular characteristics and functional properties of the Glu-B3h gene using the wheat cultivar CB037B and its Glu-B3 deletion line CB037C. The results showed that the Glu-B3h deletion had no significant effects on plant morphological or yield traits, but resulted in a clear reduction in protein body number and size and main quality parameters, including inferior mixing property, dough strength, loaf volume, and score. Molecular characterization showed that the Glu-B3h gene consists of 1179 bp, and its encoded B-subunit has a longer repetitive domain and an increased number of α-helices, as well as higher expression, which could contribute to superior flour quality. The SNP-based allele-specific PCR markers designed for the Glu-B3h gene were developed and validated with bread wheat holding various alleles at Glu-B3 locus, which could effectively distinguish the Glu-B3h gene from others at the Glu-B3 locus, and have potential applications for wheat quality improvement through marker-assisted selection.

Highlights

Low molecular weight glutenin subunit is one of the important quality elements in wheat (Triticum aestivum L.)
The CB037B developed in Beijing, Yinchuan and Xining showed significant difference in agronomic traits and yield performance, and the same trend appeared in the CB037C which were planted in these three locations, which demonstrating that environmental factors have significant effects on agronomic traits and yield performance
reversed-phase ultra performance liquid chromatography (RP-UPLC) further confirmed the absence of one abundant LMW B-subunit encoded by Glu-B3h in CB037C, which eluted after 16.44 min (Fig. 1c)

Summary

Introduction

Low molecular weight glutenin subunit is one of the important quality elements in wheat (Triticum aestivum L.). The seed storage proteins in wheat consist of monomeric gliadins and polymeric glutenins that determine the extensibility and elasticity of dough, respectively[2,3] According to their mobility, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), polymeric glutenins are subdivided into high and low molecular weight glutenin subunits (HMW-GS and LMW-GS, respectively), of which, LMW-GS accounts for ~60% of the glutenins and primarily determines dough strength and viscosity, playing a significant role in flour processing quality[4,5]. The molecular structure of LMW-GS contains four typical regions: (1) a signal peptide containing 20 amino acids removed in the maturation process, (2) a short N-terminal region with 13 amino acids containing one cysteine, (3) a repetitive domain rich with glutamine containing 70–186 amino acids as the variable region of gene size, and (4) a C-terminus rich with cysteine and glutamine. Dong et al.[1] identified four, three, and seven LMW-GS genes at the Glu-A3, Glu-B3, and Glu-D3 loci, respectively, in Xiaoyan 54

Methods

Results

Conclusion