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.

Xiaolong Liu;Xianzhi Xie;Chongke Zheng;Lixing Wei;Xiaowei Li;Yangyang Jin;Guohui Zhang;Chang-Jie Jiang;Zhengwei Liang

Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun 130102,Jilin,China;College of Life Science and Resources and Environment,Yichun University,Yichun 336000,Jiangxi,China;Shandong Rice Research Institute,Shandong Academy of Agricultural Sciences,Jinan 250100,Shandong,China;Dongying Academy of Agricultural Sciences,Dongying 257091,Shandong,China;College of Life Sciences,Engineering Research Center of the Chinese Ministry of Education for Bioreactor and Pharmaceutical Development,Jilin Agricultural University,Changchun 130118,Jilin,China;Da'an Sodic Land Experiment Station,Da'an 131317,Jilin,China;Institute of Agrobiological Sciences,NARO,Kannondai 2-1-2,Tsukuba 305-8602,Japan

作物学报（英文版）

[1]Xiaolong Liu;Xianzhi Xie;Chongke Zheng;Lixing Wei;Xiaowei Li;Yangyang Jin;Guohui Zhang;Chang-Jie Jiang;Zhengwei Liang-.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.))[J].作物学报（英文版）,2022(02):354-367

OsABA8ox1,Dongdao,plasmalemma,K+ratio

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