Regulation of mitochondrial NAD pool via NAD^+ transporter 2 is essential for matrix NADH homeostasis and ROS production in Arabidopsis

作     者：Lilan Luo Yajun He Yannan Zhao Qian Xu Jian Wu Haiyan Ma Hongyan Guo Lin Bai Jianru Zuo Jian-Min Zhou Hong Yu Jiayang Li 

作者机构：State Key Laboratory of Plant Genomics and National Center for Plant Gene ResearchInstitute of Genetics and Developmental BiologyTheInnovative Academy of Seed DesignChinese Academy of SciencesBeijing100101China University of Chinese Academy of SciencesBeijing100049China Department of Plant SciencesWeizmann Institute of ScienceRehovot 7610001Israel 

出 版 物：《Science China(Life Sciences)》 (中国科学（生命科学英文版）)

年 卷 期：2019年第62卷第8期

页      面：991-1002页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 09[农学] 071007[理学-遗传学] 0901[农学-作物学] 090102[农学-作物遗传育种] 

基　　金：supported by the National Natural Science Foundation of China (31521001  91854103  31661143025) 

主　　题：mitochondrial NAD pool NAD^+ transporter 2 mtROS 

摘      要：Reactive oxygen species(ROS) play a crucial role in numerous biological processes in plants, including development, responses to environmental stimuli, and programmed cell death(PCD). Deficiency in MOSAIC DEATH 1(MOD1), a plastid-localized enoyl-ACP reductase essential for de novo fatty acid biosynthesis in Arabidopsis thaliana, leads to the increased malate export from chloroplasts to mitochondria, and the subsequent accumulation of mitochondria-generated ROS and PCD. In this study, we report the identification and characterization of a mod1 suppressor, som592. SOM592 encodes mitochondrion-localized NAD^+ transporter 2(NDT2). We show that the mitochondrial NAD pool is elevated in the mod1 mutant. The som592 mutation fully suppressed mitochondrial NADH hyper-accumulation, ROS production, and PCD in the mod1 mutant, indicating a causal relationship between mitochondrial NAD accumulation and ROS/PCD phenotypes. We also show that in wild-type plants, the mitochondrial NAD+uptake is involved in the regulation of ROS production in response to continuous photoperiod. Elevation of the alternative respiration pathway can suppress ROS accumulation and PCD in mod1, but leads to growth restriction. These findings uncover a regulatory mechanism for mitochondrial ROS production via NADH homeostasis in Arabidopsis thaliana that is likely important for growth regulation in response to altered photoperiod.