Diurnal Changes in Water Soluble Carbohydrate Components in Leaves and Sucrose Associated TaSUT1 Gene Expression during Grain Development in Wheat.

Sarah Al-Sheikh Ahmed,Zitong Yu,Wim Van Den Ende,Andrew Foreman,Sanda Cricelli,Bernard Dell,Shahidul Islam,Jiansheng Chen,Jingjuan Zhang,Wujun Ma,Hussein Farhan,Yingquan Zhang

doi:10.3390/ijms21218276

Sarah Al-Sheikh Ahmed, Zitong Yu + Show 10 more

Open Access

https://doi.org/10.3390/ijms21218276

Copy DOI

Abstract

In plant tissues, sugar levels are determined by the balance between sugar import, export, and sugar synthesis. So far, water soluble carbohydrate (WSC) dynamics have not been investigated in a diurnal context in wheat stems as compared to the dynamics in flag leaves during the terminal phases of grain filling. Here, we filled this research gap and tested the hypothesis that WSC dynamics interlink with gene expression of TaSUT1. The main stems and flag leaves of two genotypes, Westonia and Kauz, were sampled at four hourly intervals over a 24 h period at six developmental stages from heading to 28 DAA (days after anthesis). The total levels of WSC and WSC components were measured, and TaSUT1 gene expression was quantified at 21 DAA. On average, the total WSC and fructan levels in the stems were double those in the flag leaves. In both cultivars, diurnal patterns in the total WSC and sucrose were detected in leaves across all developmental stages, but not for the fructans 6-kestose and bifurcose. However, in stems, diurnal patterns of the total WSC and fructan were only found at anthesis in Kauz. The different levels of WSC and WSC components between Westonia and Kauz are likely associated with leaf chlorophyll levels and fructan degradation, especially 6-kestose degradation. High correlation between levels of TaSUT1 expression and sucrose in leaves indicated that TaSUT1 expression is likely to be influenced by the level of sucrose in leaves, and the combination of high levels of TaSUT1 expression and sucrose in Kauz may contribute to its high grain yield under well-watered conditions.

Highlights

Improving and sustaining grain yield remains a priority for wheat production as the world population increases [1]
Similar to glucose patterns, the fructose concentrations of Westonia gradually increased from 1.4% to a significant level of 3% while it was relatively stable in Kauz
Diurnal effects on water soluble carbohydrate (WSC) and WSC components in leaves and stems of Westonia and Kauz were quantified from heading until 28 DAA in a glasshouse experiment

Summary

Introduction

Improving and sustaining grain yield remains a priority for wheat production as the world population increases [1]. The sum of glucose, fructose, sucrose and fructans, hereafter termed “water soluble carbohydrate” (WSC) in wheat stems and leaf sheaths is one of the crucial parameters contributing to grain yield especially under terminal drought conditions [5,6,7,8,9]. Photosynthesis from leaves, sheath, culm, and ears contributes to the total photosynthetic capacity in wheat [11]. Flag leaf area photosynthesis correlates well with the grain yield in wheat [12]. Chlorophyll is an important photosynthetic pigment largely contributing photosynthetic capacity [13]. Chlorophyll fluorescence provides a signature of photosynthesis and can be measured with portable chlorophyll fluorometers [14]

Objectives

Methods

Findings

Conclusion