RNAi-mediated suppression of the abscisic acid catabolism gene OsABA8ox1 increases abscisic acid content and tolerance to saline-alkaline stress in rice(Oryza sativa L.)

• 作者: Xiaolong Liu Xianzhi Xie Chongke Zheng Lixing Wei Xiaowei Li Yangyang Jin Guohui Zhang Chang-Jie Jiang Zhengwei Liang
• 来源期刊: 作物学报（英文版）
• 年，卷（期）: 2022,（2）
• 所属期刊栏目: Research Papers
• 页码范围: 354-367
• 页数: 14页
• 语种: 英文

摘要

Saline-alkaline(SA)stress is characterized by high salinity and high alkalinity(high pH),which severely inhibit plant growth and cause huge losses in crop yields worldwide.Here we show that a moderate ele-vation of endogenous abscisic acid(ABA)levels by RNAi-mediated suppression of OsABA8ox1(OsABA8ox1-kd),a key ABA catabolic gene,significantly increased tolerance to SA stress in rice plants.We produced OsABA8ox1-kd lines in two different japonica cultivars,Dongdao 4 and Nipponbare.Compared with non-transgenic control plants(WT),the OsABA8ox1-kd seedlings accumulated 25.9％-55.7％higher levels of endogenous ABA and exhibited reduced plasmalemma injury,ROS accumulation and Na+/K+ratio,and higher survival rates,under hydroponic alkaline conditions simulated by 10,15,and 20 mmol L-1 of Na2CO3.In pot trials using SA field soils of different alkali levels(pH 7.59,8.86,and 9.29),OsABA8ox1-kd plants showed markedly higher seedling survival rates and more vigorous plant growth,resulting in significantly higher yield components including panicle number(85.7％-128.6％),spikelets per panicle(36.9％-61.9％),branches(153.9％-236.7％),1000-kernel weight(20.0％-28.6％),and percentage of filled spikelets(96.6％-1340.8％)at harvest time.Under severe SA soil conditions(pH=9.29,EC=834.4 pS cm-1),OsABA8ox1-kd lines showed an 194.5％-1090.8％increase in grain yield per plant relative to WT plants.These results suggest that suppression of OsABA8ox1 to increase endogenous ABA levels provides a new molecular approach for improving rice yield in SA paddies.