1. Phosphorylation of a NAC Transcription Factor by a Calcium/Calmodulin-Dependent Protein Kinase Regulates Abscisic Acid-Induced Antioxidant Defense in Maize
- Author
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Zhu, Yuan, Yan, Jingwei, Liu, Weijuan, Liu, Lei, Sheng, Yu, Sun, Yue, Li, Yanyun, Scheller, Henrik Vibe, Jiang, Mingyi, Hou, Xilin, Ni, Lan, and Zhang, Aying
- Subjects
Plant Biology ,Biological Sciences ,Genetics ,Abscisic Acid ,Antioxidants ,Calcium-Calmodulin-Dependent Protein Kinases ,Droughts ,Gene Expression Regulation ,Plant ,Hydrogen Peroxide ,Phosphorylation ,Plant Proteins ,Plants ,Genetically Modified ,Seedlings ,Serine ,Tobacco ,Transcription Factors ,Zea mays ,Agricultural and Veterinary Sciences ,Plant Biology & Botany ,Plant biology - Abstract
Calcium/calmodulin-dependent protein kinase (CCaMK) has been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense and enhance the tolerance of plants to drought stress. However, its downstream molecular events are poorly understood. Here, we identify a NAC transcription factor, ZmNAC84, in maize (Zea mays), which physically interacts with ZmCCaMK in vitro and in vivo. ZmNAC84 displays a partially overlapping expression pattern with ZmCCaMK after ABA treatment, and H2O2 is required for ABA-induced ZmNAC84 expression. Functional analysis reveals that ZmNAC84 is essential for ABA-induced antioxidant defense in a ZmCCaMK-dependent manner. Furthermore, ZmCCaMK directly phosphorylates Ser-113 of ZmNAC84 in vitro, and Ser-113 is essential for the ABA-induced stimulation of antioxidant defense by ZmCCaMK. Moreover, overexpression of ZmNAC84 in tobacco (Nicotiana tabacum) can improve drought tolerance and alleviate drought-induced oxidative damage of transgenic plants. These results define a mechanism for ZmCCaMK function in ABA-induced antioxidant defense, where ABA-produced H2O2 first induces expression of ZmCCaMK and ZmNAC84 and activates ZmCCaMK. Subsequently, the activated ZmCCaMK phosphorylates ZmNAC84 at Ser-113, thereby inducing antioxidant defense by activating downstream genes.
- Published
- 2016