title: Potassium (K+) gradients serve as a mobile energy source in plant vascular tissues.
abstract: 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.
authors.affiliation: Heisenberg Group of Biophysics and Molecular Plant Biology, Institute of Biochemistry and Biology, University of Potsdam, D-14476 Potsdam-Golm, Germany.
authors.forename: Pawel
authors.initials: P
authors.lastname: Gajdanowicz
authors.forename: Erwan
authors.initials: E
authors.lastname: Michard
authors.forename: Michael
authors.initials: M
authors.lastname: Sandmann
authors.forename: Marcio
authors.initials: M
authors.lastname: Rocha
authors.forename: Luiz Gustavo Guedes
authors.initials: LG
authors.lastname: Corrêa
authors.forename: Santiago J
authors.initials: SJ
authors.lastname: Ramírez-Aguilar
authors.forename: Judith L
authors.initials: JL
authors.lastname: Gomez-Porras
authors.forename: Wendy
authors.initials: W
authors.lastname: González
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Thibaud
authors.forename: Joost T
authors.initials: JT
authors.lastname: van Dongen
authors.forename: Ingo
authors.initials: I
authors.lastname: Dreyer
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics; D019295:Computational Biology / Q000379:methods; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018745:Genome, Plant; D008954:Models, Biological; D008957:Models, Genetic; D008962:Models, Theoretical; D009154:Mutation; D010100:Oxygen / Q000737:chemistry; D010641:Phenotype; D018521:Plant Physiological Phenomena; D011188:Potassium / Q000737:chemistry*; D015221:Potassium Channels / Q000235:genetics; D011499:Protein Processing, Post-Translational
chemical_list: C097485:AKT2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D015221:Potassium Channels; D011188:Potassium; D010100:Oxygen