Effects of Nitrogen Fertilizer on Quality Characteristics of Wheat with the Absence of Different Individual High-Molecular-Weight Glutenin Subunits (HMW-GSs).

Tao Yang,Jian Cai,Mei Huang,Xiao Wang,Qi Wang,Dong Jiang,Qin Zhou

doi:10.3390/ijms23042178

Abstract

High-molecular-weight glutenin subunits (HMW-GSs) are important components of gluten, which determine the grain quality of wheat. In this study, we investigated the effects of nitrogen (N) fertilizer application on the synthesis and accumulation of grain protein and gluten quality in wheat lines with different HMW-GSs absent. The results showed that the absence of the HMW-GS in the wheat variety Ningmai 9 significantly decreased the contents of gluten, glutenin macropolymer (GMP), protein compositions, HMW-GS and HMW-GS/LMW-GS. The reduction in glutenins was compensated to some extent by an increase of gliadins. The absence of x-type HMW-GSs (1, 7 and 2 subunits) had a greater effect on gluten and GMP properties than y-type HMW-GSs (8 and 12 subunits). The content of protein compositions, gluten and GMP increased with an increase of N level; however, the increment in wheat lines with the absence of HMW-GS, especially in Ax1a, Bx7a and Dx2a, was lower than that in the wild type under various N levels. The expression level of genes encoding HMW-GSs, and activities of nitrate reductase (NR) and glutamine synthetase (GS), differed significantly among the investigated wheat lines. The reduction in gene expression and activities in Ax1a and Dx2a may account for the reductions in gluten, GMP, protein compositions, HMW-GS and HMW-GS/LMW-GS.

Highlights

Five wheat lines were absent in the High-molecular-weight glutenin subunits (HMW-glutamine synthetase (GS)) of Ax1, Bx7, By8, Dx2, and Dy12, respectively, which was designated as Ax1a, Bx7a, By8a, Dxa2 and Dy12a, and the wide type was designated as WT
The grain yields in the wheat lines with HWM-GS in Ningmai 9 increased with the increase of N levels, and the absence of HMW-GS significantly decreased the content of wet gluten, free SH, glutenin macropolymer (GMP), protein composition, HMW-GS
The content of protein, gluten, GMP, SH, protein composition and subunits increased with the increase of N application

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Wheat (Triticum aestivum L.) is a staple food crop for humans in the world [1]. The unique elasticity and extensibility of dough enables wheat flour to be processed into a wide range of foods, such as bread, biscuit and noodles. The elasticity and extensibility are conferred by gluten proteins classified as gliadins and glutenins. The gliadins are monomeric proteins, whereas glutenins are polymeric proteins and are further divided into high-molecular-weight subunits (HMW-GSs, 65–90+ KDa) and low-molecular-weight subunits (LMW-GSs, 30–60 KDa) [2]. HMW-GSs account for ~10% of grain protein, they are major determinants of gluten elasticity and functionality [3]

Methods

Results

Discussion

Conclusion