Grain Yield, Starch Content and Activities of Key Enzymes of Waxy and Non-waxy Wheat (Triticum aestivum L.)

Yan Zi,Wenshan Guo,Xinkai Zhu,Chunyan Li,Jianmin Song,Jinfeng Ding,Yongxin Peng,Gavin Humphreys

doi:10.1038/s41598-018-22587-0

Abstract

Waxy wheat has unique end-use properties; however, its production is limited due mainly to its low grain yield compared with non-waxy wheat. In order to increase its grain yield, it is critical to understand the eco-physiological differences in grain filling between the waxy and non-waxy wheat. In this study, two waxy wheat and two non-waxy wheat cultivars were used to investigate the differences in starch-associated enzymes processes, sucrose and starch dynamics, yield components, and the final grain yield. The results indicated that the mean total grain starch and amylose content, the average 1000-kernel weight and grain yield of the waxy wheat were lower than those of the non-waxy wheat at maturity. The amylose content was significantly and positively correlated with the activity of GBSS (r = 0.80, p < 0.01). Significant positive correlation also exists among activities of AGPase, SSS, GBSS, and SBE, except for GBSS-SBE. In summary, our study has revealed that the reduced conversion of sucrose to starch in the late grain filling stage is the main cause for the low kernel weight and total starch accumulation of the waxy wheat. The reduced conversion also appears to be a factor contributing to the lower grain yield of the waxy wheat.

Highlights

Waxy wheat has unique end-use properties; its production is limited due mainly to its low grain yield compared with non-waxy wheat
No significant differences in amylopectin levels were detected between waxy and non-waxy wheat cultivars
Our study suggests that low ADPG pyrophosphorylase (AGPase) activity could be the cause of low total starch content in waxy wheat grain, and low granule bound starch synthase (GBSS) activity could be the contributing factor to insufficient amylose content

Summary

Introduction

Waxy wheat has unique end-use properties; its production is limited due mainly to its low grain yield compared with non-waxy wheat. The results indicated that the mean total grain starch and amylose content, the average 1000-kernel weight and grain yield of the waxy wheat were lower than those of the non-waxy wheat at maturity. Our study has revealed that the reduced conversion of sucrose to starch in the late grain filling stage is the main cause for the low kernel weight and total starch accumulation of the waxy wheat. The Wx proteins are known as granule-bound starch synthases, which have a role in the synthesis of amylose[1,2,3,4,5]. Strength, which is an important limiting factor to wheat grain yield, and the activity of SUS can be considered as an indicator of sink strength[8,10,11]. SBE that was formerly known as Q-enzyme plays an important role on amylopectin synthesis, which is the only plant enzyme that can introduce α-1,6-glucosidic linkages into α-polyglucans[18,19]

Methods

Results

Discussion

Conclusion