title: Venus Flytrap HKT1-Type Channel Provides for Prey Sodium Uptake into Carnivorous Plant Without Conflicting with Electrical Excitability.
abstract: The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na(+)- and K(+)-permeable mutants function as ion channels rather than K(+) transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na(+)-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.
authors.affiliation: Julius-von-Sachs Institute, Department for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Böhm
authors.affiliation: Julius-von-Sachs Institute, Department for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Scherzer
authors.affiliation: School of Land and Food, University of Tasmania, Hobart TAS 7001, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Shabala
authors.affiliation: Julius-von-Sachs Institute, Department for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Krol
authors.affiliation: Zoology Department, College of Science, King Saud University, PO Box 2455, Riyadh 11451, Saudi Arabia; Department for Membrane Biophysics, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Neher
authors.affiliation: Julius-von-Sachs Institute, Department for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany. Electronic address: mueller@botanik.uni-wuerzburg.de.
authors.forename: T D
authors.initials: TD
authors.lastname: Mueller
authors.affiliation: Julius-von-Sachs Institute, Department for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany. Electronic address: hedrich@botanik.uni-wuerzburg.de.
authors.forename: R
authors.initials: R
authors.lastname: Hedrich
mesh_terms: D000818:Animals; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D031257:Droseraceae / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D055724:Electrophysiological Phenomena; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011235:Predatory Behavior; D012964:Sodium / Q000378:metabolism*
chemical_list: D027682:Cation Transport Proteins; D010940:Plant Proteins; D012964:Sodium
keywords: Dionaea muscipula; HKT1; action potential; glands; sodium channel; sodium uptake