Characterization of Changes in Gluten Proteins in Low-Gliadin Transgenic Wheat Lines in Response to Application of Different Nitrogen Regimes.

María Dolores García-Molina,Francisco Barro

doi:10.3389/fpls.2017.00257

María Dolores García-Molina, Francisco Barro

Open Access

https://doi.org/10.3389/fpls.2017.00257

Copy DOI

Abstract

Gluten proteins are major determinants of the bread making quality of wheat but also of important gluten-related disorders. The gluten protein accumulation during grain filling is strongly influenced by nitrogen fertilization. We have characterized the gluten proteins in low-gliadin wheat lines as influenced by nitrogen treatments in two experiments. These transgenic lines, D783, D793, C655, D577, and E82 were obtained by using two different RNAi silencing fragments and two endosperm-specific promoters to drive the silencing fragments (d-hordein and γ-gliadin). In Experiment 1, we used three nitrogen fertilizer rates (120, 360, and 1080 mg N) added at sowing stage and combined with two sulfur rates (8 and 30 mg S); Experiment 2 included two nitrogen levels (120 and 1080 mg N), which were added according to the greatest demand per plant using split applications. The protein quantification was accomplished by Reverse-Phase High-Performance Liquid Chromatography and gluten content (ppm) determined using monoclonal antibody R5 (Competitive R5 ELISA). The results showed differences in protein accumulation between the two transgenic lines with the same silencing fragment but different promoter. Lines D793 and E82 showed low gliadin and an increment in glutenin content with increasing nitrogen. Competitive ELISA R5 showed a significant decrease in gluten content using split applications of nitrogen (Experiment 2) with 120 mg N compared to Experiment 1. In addition, line E82 ensures that variations in N fertilization will not result in increased gluten content.

Highlights

Wheat is one of the most important crops in the world, providing energy and protein for humans and animals
Wheat flour is used to make a wide variety of products including cakes, pasta, bread, noodles, and biscuits, which is Abbreviations: CD, celiac disease; GFD, gluten-free diet; HMW-GS, high molecular weight glutenin subunits; LMW-GS, low molecular weight glutenin subunits; LSD, least significant difference; NCGS, non-celiac gluten sensitivity; ppm, parts per million; Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC), reverse-phase HPLC; SE-HPLC, size exclusion HPLC
Gliadins and glutenins were determined by RP-HPLC. 120, 360, and 1080 are the N treatments expressed in mg of N

Summary

Introduction

Wheat is one of the most important crops in the world, providing energy and protein for humans and animals. Nitrogen and Low-Gliadin wheat possibly because of the gluten proteins in wheat, which consist of gliadins and glutenins (Shewry et al, 2009). Shewry et al (1986) classified the wheat prolamins on the basis of their sulfur content into S-poor, consisting of ω-gliadins; S-rich composed of α- and γ-gliadins and the LMW-GS; and HMW-GS prolamins. Gluten plays an important role in the final quality of wheat as its proteins form a cohesive viscoelastic network that allows the trapping of carbon dioxide during the fermentation and expansion of the dough, contributing to the final volume and texture of bread and other baked products

Objectives

Methods

Results

Discussion

Conclusion