AtWNK9 is regulated by ABA and dehydration and is involved in drought tolerance in Arabidopsis

• Published in: Plant physiology and biochemistry Vol. 77; pp. 73 - 83
• Main Authors: Xie, Minmin, Wu, Dan, Duan, Guifang, Wang, Liqun, He, Reqing, Li, Xiushan, Tang, Dongying, Zhao, Xiaoying, Liu, Xuanming
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01.04.2014; Elsevier
• Subjects: ABA; Abscisic Acid - metabolism; Abscisic Acid - pharmacology; Adaptation, Physiological - genetics; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; AtWNK9; Biological and medical sciences; DNA, Bacterial; Drought tolerance; Droughts; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes, Plant; Mutagenesis, Insertional; Plant physiology and development; Plants, Genetically Modified; Signal Transduction; Stress, Physiological - genetics; Water; ABA; Arabidopsis; Drought tolerance; AtWNK9; Tolerance; Dehydration; Arabidopsis thaliana; Plant physiology; Cruciferae; Drought resistance; Dicotyledones; Sesquiterpenes; Angiospermae; Abscisic acid; Plant growth substance; Spermatophyta; Experimental plant
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2014.01.022

WNK (with no lysine [K]) kinases play important regulatory roles in flowering, as well as salt and osmotic stress tolerance in plants. Here, we report that AtWNK9, a member of the Arabidopsis WNK gene family, was induced by exogenous abscisic acid (ABA) treatment and dehydration stress. Overexpression of AtWNK9 from the cauliflower mosaic virus 35S promoter in Arabidopsis resulted in increased sensitivity to ABA, strong inhibition of primary root elongation, increased proline accumulation, reduced stomatal aperture, and a reduced rate of water loss. In addition, plant survival under drought stress was improved compared to wild type. In contrast, a mutant with a T-DNA insertion in AtWNK9 showed reduced ABA sensitivity and an increased rate of water loss; further, it showed increased susceptibility to drought stress. The transcription of a number of ABA signaling components, including ABI1, ERA1, ABI3, and ABF3, was up-regulated in AtWNK9 transgenic plants and down-regulated in the wnk9 mutant in response to ABA. Some ABA-responsive and biosynthetic genes, as well as other drought-related genes, were altered at various levels in AtWNK9 transgenic plants and wnk9 mutants under dehydration stress. Overall, these findings suggest that AtWNK9 plays a positive role in ABA signaling and improves drought tolerance in transgenic Arabidopsis. •Expression of AtWNK9 is induced by ABA and dehydration.•AtWNK9 transgenic Arabidopsis has enhanced sensitivity to ABA and drought tolerance.•Mutation in AtWNK9 results in reduced sensitivity to ABA and drought tolerance.•Expression levels of ABA-related genes are altered in AtWNK9 transgenic plants.•Expression levels of drought-related genes are altered in AtWNK9 transgenic plants.