Jesús Amo, Alberto Lara, Almudena Martínez‐Martínez, Vicente Martínez, Francisco Rubio, Manuel Nieves‐Cordones

15
Sep 20, 2021
Plant, Cell & Environment
DOI :
10.1111/pce.14189
Article
show_chart

Regulation of root transport systems is essential under fluctuating nutrient supply. In the case of potassium (K+), HAK/KUP/KT K+ transporters and voltage‐gated K+ channels ensure root K+ uptake in a wide range of K+ concentrations. In Arabidopsis, the CIPK23/CBL1‐9 complex regulates both transporter‐ and channel‐mediated root K+ uptake. However, research about K+ homeostasis in crops is in demand due to species‐specific mechanisms. In the present manuscript, we studied the contribution of the voltage‐gated K+ channel LKT1 and the protein kinase SlCIPK23 to K+ uptake in tomato plants by analyzing gene‐edited knock‐out tomato mutant lines, together with two‐electrode voltage‐clamp experiments in Xenopus oocytes and protein‐protein interaction analyses. It is shown that LKT1 is a crucial player in tomato K+ nutrition by contributing ~50% to root K+ uptake under K+‐sufficient conditions. Moreover, SlCIPK23 was responsible for ~100% of LKT1 and ~40% of the SlHAK5 K+ transporter activity in planta. Mg+2 and Na+ compensated for K+ deficit in tomato roots to a large extent and the accumulation of Na+ was strongly dependent on SlCIPK23 function. The role of CIPK23 in Na+ accumulation in tomato roots was not conserved in Arabidopsis, which expands the current set of CIPK23‐like protein functions in plants. This article is protected by copyright. All rights reserved.
Please Log In to leave a comment.