Arabidopsis K+ transporter HAK5-mediated high-affinity root K+ uptake is regulated by protein kinases CIPK1 and CIPK9. (2nd June 2020)

• Record Type: Journal Article
• Authors: Lara, Alberto; Ródenas, Reyes; Andrés, Zaida; Martínez, Vicente; Quintero, Francisco J; Nieves-Cordones, Manuel; Botella, M Angeles; Rubio, Francisco
• Editors: Dietz, Karl-Josef
• Is Part Of: Journal of experimental botany. Volume 71:Number 16(2020)
• Page Start: 5053
• Page End: 5060
• Publication Date: 2020-06-02
• Subjects: Arabidopsis -- AtCBL -- AtCIPK -- AtHAK5 -- potassium -- uptake; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/eraa212
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract : Arabidopsis protein kinases CIPK1 and CIPK9, in addition to CIPK23, regulate K + transporter HAK5-mediated K + uptake, and their genes were induced by K + deprivation. Abstract: The high-affinity K + transporter HAK5 is the major contributor to root K + uptake from dilute solutions in K + -starved Arabidopsis plants. Its functionality is tightly regulated and its activity is enhanced under K + starvation by the transcriptional induction of the AtHAK5 gene, and by the activation of the transporter via the AtCBL1–AtCIPK23 complex. In the present study, the 26 members of the Arabidopsis CIPK protein kinase family were screened in yeast for their capacity to activate HAK5-mediated K + uptake. Among them, AtCIPK1 was the most efficient activator of AtHAK5. In addition, AtCIPK9, previously reported to participate in K + homeostasis, also activated the transporter. In roots, the genes encoding AtCIPK1 and AtCIPK9 were induced by K + deprivation and atcipk1 and atcipk9 Arabidopsis KO mutants showed a reduced AtHAK5-mediated Rb + uptake. Activation of AtHAK5 by AtCIPK1 did not occur under hyperosmotic stress conditions, where AtCIPK1 function has been shown to be required to maintain plant growth. Taken together, our data contribute to the identification of the complex regulatory networks that control the high-affinity K + transporter AtHAK5 and root K + uptake.