Potassium (K+) gradients serve as a mobile energy source in plant vascular tissues.

Pawel Gajdanowicz (1) , Erwan Michard (1, 2) , Michael Sandmann (1) , Marcio Rocha (3) , Luiz Gustavo Guedes Corrêa (1, 3) , Santiago J Ramírez-Aguilar (3) , Judith L Gomez-Porras (1) , Wendy González (1, 4) , Jean-Baptiste Thibaud (2) , Joost T van Dongen (3) , Ingo Dreyer (1)

1 Heisenberg Group of Biophysics and Molecular Plant Biology
2 BPMP - Biochimie et Physiologie Moléculaire des Plantes
3 MPI-MP - Max-Planck-Institut für Molekulare Pflanzenphysiologie
4 Centro de Bioinformática y Simulación Molecular

The essential mineral nutrient potassium (K(+)) is the most important inorganic cation for plants and is recognized as a limiting factor for crop yield and quality. Nonetheless, it is only partially understood how K(+) contributes to plant productivity. K(+) is used as a major active solute to maintain turgor and to drive irreversible and reversible changes in cell volume. K(+) also plays an important role in numerous metabolic processes, for example, by serving as an essential cofactor of enzymes. Here, we provide evidence for an additional, previously unrecognized role of K(+) in plant growth. By combining diverse experimental approaches with computational cell simulation, we show that K(+) circulating in the phloem serves as a decentralized energy storage that can be used to overcome local energy limitations. Posttranslational modification of the phloem-expressed Arabidopsis K(+) channel AKT2 taps this "potassium battery," which then efficiently assists the plasma membrane H(+)-ATPase in energizing the transmembrane phloem (re)loading processes.

Mots clés: channel gating; energy limiting condition; phloem reloading; posttranslational regulation; potassium channel

Domaines: Biologie végétale

Pawel Gajdanowicz, Erwan Michard, Michael Sandmann, Marcio Rocha, Luiz Gustavo Guedes Corrêa, et al.. Potassium (K+) gradients serve as a mobile energy source in plant vascular tissues.. Proceedings of the National Academy of Sciences of the United States of America, 2011, 108 (2), pp.864-9. ⟨10.1073/pnas.1009777108⟩. ⟨hal-00555632⟩