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

作者：Xiaolong Liu, Xin Zhong, Junrui Liao, Ping Ji, Jinshuo Yang, Zhiruo Cao, Ximiao Duan, Junru Xiong, Ying Wāng, Xu Chen, Hongtao Yang, Bo Peng, Kai Jiang · 发表于：BMC Plant Biology · 年份：2023 · DOI：10.1186/s12870-023-04638-5 · 被引用次数：43 · 研究领域：Rice Cultivation and Yield Improvement、Plant Stress Responses and Tolerance、GABA and Rice Research

Abstract 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 c...