NtCIPK9: A Calcineurin B-Like Protein-Interacting Protein Kinase From the Halophyte Nitraria tangutorum, Enhances Arabidopsis Salt Tolerance

Lu Lu; Xinying Chen; Liming Zhu; Mengjuan Li; Jingbo Zhang; Xiuyan Yang; Pengkai Wang; Ye Lu; Tielong Cheng; Jisen Shi; Yin Yi; Jinhui Chen

doi:10.3389/fpls.2020.01112

NtCIPK9: A Calcineurin B-Like Protein-Interacting Protein Kinase From the Halophyte Nitraria tangutorum, Enhances Arabidopsis Salt Tolerance

Front Plant Sci. 2020 Aug 21:11:1112. doi: 10.3389/fpls.2020.01112. eCollection 2020.

Authors

Lu Lu¹, Xinying Chen¹, Liming Zhu¹, Mengjuan Li¹, Jingbo Zhang², Xiuyan Yang³, Pengkai Wang¹, Ye Lu¹, Tielong Cheng¹, Jisen Shi¹, Yin Yi^{4

5}, Jinhui Chen¹

Affiliations

¹ Key Laboratory of Forestry Genetics & Biotechnology of Ministry of Education, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
² Experimental Center of Desert Forestry, Chinese Academy of Forestry, Dengkou, China.
³ Research Center of Saline and Alkali Land of National Forestry and Grassland Administration, China Academy of Forestry, Beijing, China.
⁴ State Forestry Administration Key Laboratory of Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Guizhou Normal University, Guiyang, China.
⁵ Guizhou Provincial Key Laboratory of Plant Physiology and Developmental Regulation, Guizhou Normal University, Guiyang, China.

Abstract

Calcineurin B-like protein-interacting protein kinases (CIPKs) play essential roles in plant abiotic stress response. In order to better understand salt tolerance, we cloned and analyzed the NtCIPK9 gene from the halophyte Nitraria tangutorum. Phylogenetic analysis shows that NtCIPK9 belongs to a sister clade with the Arabidopsis AtCIPK9 gene and is thought to localize to the plasma membrane. NtCIPK9 shows the highest expression level in the Nitraria tangutorum root under normal growth conditions, whereas after NaCl treatment, the highest expression was found in the blade. NtCIPK9-overexpressing Arabidopsis plants have a higher seed germination rate, longer root length, and displayed higher salt tolerance than wild type seedlings under salt stress conditions. Furthermore, NtCIPK9 overexpression might enhance the expression of genes related to K⁺ transportation after NaCl treatment. Thus, we conclude that NtCIPK9 increases transgenic plant salt tolerance and reduces damage associated with salt stress by promoting the expression of genes controlling ion homeostasis. Our results suggest that NtCIPK9 could serve as an ideal candidate gene to genetically engineer salt-tolerant plants.

Keywords: CIPK9; Nitraria tangutorum; halophyte; ion homeostasis; salt tolerance.