Journal Article

Exogenous abscisic acid improves grain filling capacity under heat stress by enhancing antioxidative defense capability in rice

Zhong, Xin, Cao, Zhiruo, Ji, Ping, Liu, Xiaolong, Xu, Chen, Peng, Bo, Wang, Ying, Yang, Hongtao, Jiang, Kai, Liao, Jingpeng, Xiong, Junru, Duan, Ximiao, Yang, Jinshuo

2023

Overview

Background Heat stress is a major restrictive factor that causes yield loss in rice. We previously reported the priming effect of abscisic acid (ABA) on rice for enhanced thermotolerance at the germination, seedling and heading stages. In the present study, we aimed to understand the priming effect and mechanism of ABA on grain filling capacity in rice under heat stress. Results Rice plants were pretreated with distilled water, 50 μM ABA and 10 μM fluridone by leaf spraying at 8 d or 15 d after initial heading (AIH) stage and then were subjected to heat stress conditions of 38 °C day/30 °C night for 7 days, respectively. Exogenous ABA pretreatment significantly super-activated the ABA signaling pathway and improved the SOD, POD, CAT and APX enzyme activity levels, as well as upregulated the ROS-scavenging genes; and decreased the heat stress-induced ROS content (O 2 – and H 2 O 2 ) by 15.0–25.5% in rice grain under heat stress. ABA pretreatment also increased starch synthetase activities in rice grain under heat stress. Furthermore, ABA pretreatment significantly improved yield component indices and grain yield by 14.4–16.5% under heat stress. ABA pretreatment improved the milling quality and the quality of appearance and decreased the incidence of chalky kernels and chalkiness in rice grain and improved the rice grain cooking quality by improving starch content and gel consistence and decreasing the amylose percentage under heat stress. The application of paraquat caused overaccumulation of ROS, decreased starch synthetase activities and ultimately decreased starch content and grain yield. Exogenous antioxidants decreased ROS overaccumulation and increased starch content and grain yield under heat stress. Conclusion Taken together, these results suggest that exogenous ABA has a potential priming effect for enhancing rice grain filling capacity under heat stress at grain filling stage mainly by inhibiting ROS overaccumulation and improving starch synthetase activities in rice grain.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Abscisic acid / Abscisic acid (ABA) / Abscisic Acid - metabolism / Agriculture / Amylose / Antioxidants / Antioxidants - metabolism / Biomedical and Life Sciences / Capacity / Crop yield / Crop yields / Distilled water / Edible Grain - metabolism / Environmental aspects / Enzymatic activity / Enzyme activity / Evaluation / fluridone / gels / Germination / Grain / Grain filling / grain yield / heading / Heat / Heat stress / Heat tolerance / Heat tolerance (Biology) / Heat-Shock Response / Hydrogen peroxide / Hydrogen Peroxide - metabolism / Influence / leaves / Life Sciences / Ligases / Ligases - metabolism / Ligases - pharmacology / Oryza - genetics / Paraquat / Plant Sciences / Pretreatment / Priming (coating) / Priming Rice (Oryza sativa L.) / Production management / Reactive Oxygen Species - metabolism / Rice / Salt / Scavenging / Seedlings / Seeds / Signal transduction / Spraying / Starch / Starch - metabolism / Temperature effects / Temperature tolerance / Tree Biology / yield components