title: Ion currents involved in early Nod factor response in Medicago sativa root hairs: a discontinuous single-electrode voltage-clamp study.
abstract: Nod factor [NodRm-IV(Ac,S)], isolated from the bacterium Rhizobium meliloti, induces a well-known depolarization in Medicago sativa (cv Sitel) root hairs. Analysis of this membrane response using the discontinuous single-electrode voltage-clamp technique (dSEVC) shows that anion channel, K+ channel and H+-ATPase pump currents are involved in young growing root hairs. The early Nod-factor-induced depolarization is due to increase of the inward ion current and inhibition of the H+ pump. It involved an instantaneous inward anion current (IIAC) and/or a time-dependent inward K+ current (IRKC). These two ion currents are then down-regulated while the H+ pump is stimulated, allowing long-term rectification of the membrane potential (Em). Our results support the idea that the regulation of inward current plays a primary role in the Nod-factor-induced electrical response, the nature of the ions carried by these currents depending on the activated anion and/or K+ channels at the plasma membrane.
authors.affiliation: Institut des Sciences Végétales, Centre National de la Recherche Scientifique, Bât 22, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France. armen@isv.cnrs-gif.fr
authors.forename: A
authors.initials: A
authors.lastname: Kurkdjian
authors.forename: F
authors.initials: F
authors.lastname: Bouteau
authors.forename: A M
authors.initials: AM
authors.lastname: Pennarun
authors.forename: M
authors.initials: M
authors.lastname: Convert
authors.forename: D
authors.initials: D
authors.lastname: Cornel
authors.forename: J P
authors.initials: JP
authors.lastname: Rona
authors.forename: U
authors.initials: U
authors.lastname: Bousquet
mesh_terms: D020013:Calcium Signaling / Q000187:drug effects; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism*; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D000455:Medicago sativa / Q000187:drug effects* / Q000378:metabolism* / Q000382:microbiology; D008564:Membrane Potentials / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D017494:Proton Pumps / Q000187:drug effects / Q000378:metabolism; D016962:Sinorhizobium meliloti / Q000378:metabolism
chemical_list: D007473:Ion Channels; D008070:Lipopolysaccharides; C092082:Nod factor IV, Rhizobium meliloti; D015221:Potassium Channels; D017494:Proton Pumps