Expression of a rice soluble starch synthase gene in transgenic wheat improves the grain yield under heat stress conditions

Abstract

Wheat (Triticum aestivum L.) is a temperate cereal with an optimum temperature range of 15–22°C during the grain filling stage. Heat stress is one of the major environmental constraints for wheat production worldwide. Temperatures above 25°C during the grain filling stage significantly reduced wheat yield and quality. This reduction was reported due to the inactivation of the soluble starch synthase, a key heat-labile enzyme in starch transformation of wheat endosperm. To improve wheat productivity under heat stress, the rice soluble starch synthase I, under the control of either a constitutive promoter or an endosperm-specific promoter, was expressed in wheat and the transgenic lines were monitored for expression and the effects on yield-related traits. The results showed that the transgenic wheat events expressed rice soluble starch synthase I at a high level after four generations, and transgenic plants produced grains of greater weight during heat stress. Under heat stress conditions, the thousand kernel weight increased 21–34% in T2 and T3 transgenic plants compared to the non-transgenic control plants. In addition, the photosynthetic duration of transgenic wheat was longer than in non-transgenic controls. This study demonstrated that the engineering of a heat tolerant soluble starch synthase gene can be a potential strategy to improve wheat yield under heat stress conditions.

Exploitation of Tolerance of Wheat Kernel Weight and Shape-Related Traits from Aegilops tauschii under Heat and Combined Heat-Drought Stresses

“…Drought and heat stress accelerate leaf senescence, decrease photosystem II efficiency. As a result, this leads to the reduction of the amount of stored assimilates translocated into developing grains and reduced kernel size [ 29 , 30 ]. Heat and drought affect plant growth and thereby reduce yield [ 31 ].…”

Elevated Temperatures Impose Transcriptional Constraints and Elicit Intraspecific Differences Between Coffee Genotypes

“…In Arabidopsis , homologs of UP-9A are putative interactors with ADP-glucose, which plays a key role in starch metabolism by converting glucose 1-phosphate to ADP-glucose ( Crevillén et al, 2005 ). Homologs of GRANULE-BOUND STARCH SYNTHASE (Cc08_g16970) are involved in starch and sucrose metabolism pathways and in thermotolerance acquisition ( Wang S. J. et al, 2006 ; Tian et al, 2018 ).…”

Heat Priming During Early Reproductive Stages Enhances Thermo-Tolerance to Post-anthesis Heat Stress via Improving Photosynthesis and Plant Productivity in Winter Wheat (Triticum aestivum L.)

“… Sharkey (2005) reported that under heat stress, the limited supply of photosynthate may reduce grain filling in wheat due to reduced activity of key enzymes involved in starch accumulation in the grains. In addition, Jenner (1994) indicated that in wheat, a short period of episodic temperatures above 30°C slows starch accumulation and reduces grain growth because heat stress induces denaturation of the soluble enzyme starch synthase. The effects of high temperature on photosynthesis are also associated with impaired photochemical reactions in thylakoids and carbon assimilation reactions in the chloroplast stroma ( Ristic et al, 2007 ).…”