title: The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake.
abstract: Carnivorous plants, such as the Venus flytrap (Dionaea muscipula), depend on an animal diet when grown in nutrient-poor soils. When an insect visits the trap and tilts the mechanosensors on the inner surface, action potentials (APs) are fired. After a moving object elicits two APs, the trap snaps shut, encaging the victim. Panicking preys repeatedly touch the trigger hairs over the subsequent hours, leading to a hermetically closed trap, which via the gland-based endocrine system is flooded by a prey-decomposing acidic enzyme cocktail. Here, we asked the question as to how many times trigger hairs have to be stimulated (e.g., now many APs are required) for the flytrap to recognize an encaged object as potential food, thus making it worthwhile activating the glands. By applying a series of trigger-hair stimulations, we found that the touch hormone jasmonic acid (JA) signaling pathway is activated after the second stimulus, while more than three APs are required to trigger an expression of genes encoding prey-degrading hydrolases, and that this expression is proportional to the number of mechanical stimulations. A decomposing animal contains a sodium load, and we have found that these sodium ions enter the capture organ via glands. We identified a flytrap sodium channel DmHKT1 as responsible for this sodium acquisition, with the number of transcripts expressed being dependent on the number of mechano-electric stimulations. Hence, the number of APs a victim triggers while trying to break out of the trap identifies the moving prey as a struggling Na(+)-rich animal and nutrition for the plant.
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Böhm
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: Sönke
authors.initials: S
authors.lastname: Scherzer
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Krol
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Kreuzer
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: von Meyer
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany; Naturwissenschaftliches Labor für Schüler, Friedrich-Koenig-Gymnasium, 97082 Würzburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Lorey
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Mueller
authors.affiliation: School of Land and Food, University of Tasmania, Hobart, TAS 7001, Australia.
authors.forename: Lana
authors.initials: L
authors.lastname: Shabala
authors.affiliation: Plant Molecular Genetics Department, National Centre for Biotechnology (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus University Autónoma, 28049 Madrid, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Monte
authors.affiliation: Plant Molecular Genetics Department, National Centre for Biotechnology (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus University Autónoma, 28049 Madrid, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Solano
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany; Zoology Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
authors.forename: Khaled A S
authors.initials: KA
authors.lastname: Al-Rasheid
authors.affiliation: Institute of Forest Sciences, University of Freiburg, Georges-Koehler-Allee 53/54, 79085 Freiburg, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Rennenberg
authors.affiliation: School of Land and Food, University of Tasmania, Hobart, TAS 7001, Australia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
authors.affiliation: Department for Membrane Biophysics, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany. Electronic address: eneher@gwdg.de.
authors.forename: Erwin
authors.initials: E
authors.lastname: Neher
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs Platz 2, 97082 Würzburg, Germany. Electronic address: hedrich@botanik.uni-wuerzburg.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Hedrich
mesh_terms: D000200:Action Potentials; D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism*; D031257:Droseraceae / Q000502:physiology*; D020387:Food Chain; D007313:Insecta; D054883:Oxylipins / Q000378:metabolism*; D018515:Plant Leaves / Q000502:physiology; D015398:Signal Transduction; D012964:Sodium / Q000378:metabolism*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; C011006:jasmonic acid; D012964:Sodium