K+ channel profile and electrical properties of Arabidopsis root hairs

FEBS Letters

Becker, Dirk¹  Felle, Hubert H.²  Ache, Peter¹  Hedrich, Rainer¹  Meyerhoff, Oliver¹  Ivashikina, Natalya¹ 

[1] Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany;Botany I, University of Giessen, Senckenbergstr. 17 u. 25, 35390 Giessen, Germany

关键词: Root hairs;    Potassium channel;    Nod factor;    Channel-gating;    Patch-clamp;    Ion-sensitive microelectrodes;   

DOI  :  10.1016/S0014-5793(01)03114-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Ion channels and solute transporters in the plasma membrane of root hairs are proposed to control nutrient uptake, osmoregulation and polar growth. Here we analyzed the molecular components of potassium transport in Arabidopsis root hairs by combining K⁺-selective electrodes, reverse transcription-PCR, and patch-clamp measurements. The two inward rectifiers AKT1 and ATKC1 as well as the outward rectifier GORK dominated the root hair K⁺ channel pool. Root hairs of AKT1 and ATKC1 loss-of-function plants completely lack the K⁺ uptake channel or exhibited altered properties, respectively. Upon oligochitin-elicitor treatment of root hairs, transient changes in K⁺ fluxes and membrane polarization were recorded in wild-type plants, while akt1-1 root hairs showed a reduced amplitude and pronounced delay in the potassium re-uptake process. This indicates that AKT1 and ATKC1 represent essential α-subunits of the inward rectifier. Green fluorescent protein (GFP) fluorescence following ballistic bombardment with GORK promoter-GFP constructs as well as analysis of promoter-GUS lines identified this K⁺ outward rectifier as a novel ion channel expressed in root hairs. Based on the expression profile and the electrical properties of the root hair plasma membrane we conclude that AKT1-, ATKC- and GORK-mediated potassium transport is essential for osmoregulation and repolarization of the membrane potential in response to elicitors.

【 授权许可】

Unknown