A low K+ signal is required for functional high‐affinity K+ uptake through HAK5 transporters. Issue 3 (26th May 2014)

• Record Type: Journal Article
• Authors: Rubio, Francisco; Fon, Mario; Ródenas, Reyes; Nieves‐Cordones, Manuel; Alemán, Fernando; Rivero, Rosa M.; Martínez, Vicente
• Is Part Of: Physiologia plantarum. Volume 152:Issue 3(2014:Nov.)
• Page Start: 558
• Page End: 570
• Publication Date: 2014-05-26
• Subjects: Plant physiology -- Periodicals; 571.2
• DOI: 10.1111/ppl.12205
• Languages: English
• ISSNs: 0031-9317

Abstract

<abstract abstract-type="main" id="ppl12205-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="ppl12205-para-0001">The high‐affinity K<sup>+</sup> transporter HAK5 is a key system for root K<sup>+</sup> uptake and, under very low external K<sup>+</sup>, the only one capable of supplying K<sup>+</sup> to the plant. Functional HAK5‐mediated K<sup>+</sup> uptake should be tightly regulated for plant adaptation to different environmental conditions. Thus, it has been described that the gene encoding the transporter is transcriptionally regulated, being highly induced under K<sup>+</sup> limitation. Here we show that environmental conditions, such as the lack of K<sup>+</sup>, NO<sub>3</sub><sup>−</sup> or P, that induced a hyperpolarization of the plasma membrane of root cells, induce <italic>HAK5</italic> transcription. However, only the deprivation of K<sup>+</sup> produces functional HAK5‐mediated K<sup>+</sup> uptake in the root. These results suggest on the one hand the existence of a posttranscriptional regulation of HAK5 elicited by the low K<sup>+</sup> signal and on the other that HAK5 may be involved in yet‐unknown functions related to NO<sub>3</sub><sup>−</sup> and P deficiencies. These results have been obtained here with <italic>Solanum lycopersicum</italic> (cv. Micro‐Tom) as well as <italic>Arabidopsis thaliana</italic> plants, suggesting that the posttranscriptional regulation of high‐affinity HAK transporters take place in all plant species.</p> </abstract>