Efficient allocation of the essential nutrient potassium (K+ ) is a central determinant of plant ion homeostasis and involves AKT2 K+ channels. Here, we characterize four AKT2 K+ channels from cotton and report that xylem and phloem expressed GhAKT2bD facilitates K+ allocation and that AKT2-silencing impairs plant growth and development. We uncover kinase activity-dependent activation of GhAKT2bD-mediated K+ uptake by AtCBL4-GhCIPK1 calcium signalling complexes in HEK293T cells. Moreover, AtCBL4-AtCIPK6 complexes known to convey activation of AtAKT2 in Arabidopsis also activate cotton GhAKT2bD in HEK293T cells. Collectively, these findings reveal an essential role for AKT2 in the source-sink allocation of K+ in cotton and identify GhAKT2bD as subject to complex regulation by CBL-CIPK Ca2+ sensor-kinase complexes.
Keywords: AKT2; CBL; CIPK; K+ channel; cotton; potassium allocation.
© 2022 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.