| Autor: |
Dindas J; Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, 97082, Würzburg, Germany., Scherzer S; Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, 97082, Würzburg, Germany., Roelfsema MRG; Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, 97082, Würzburg, Germany., von Meyer K; Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, 97082, Würzburg, Germany., Müller HM; Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, 97082, Würzburg, Germany., Al-Rasheid KAS; College of Science, King Saud University, Riyadh, 11451, Saudi Arabia., Palme K; Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, BIOSS Centre for Biological Signaling Studies, Centre for Biological Systems Analysis, 79104, Freiburg, Germany., Dietrich P; Molecular Plant Physiology, Department of Biology, University of Erlangen-Nürnberg, Staudtstrasse 5, 91058, Erlangen, Germany., Becker D; Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, 97082, Würzburg, Germany., Bennett MJ; Centre for Plant Integrative Biology, Plant & Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, LE12 3RD, UK., Hedrich R; Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, 97082, Würzburg, Germany. hedrich@botanik.uni-wuerzburg.de. |
| Abstrakt: |
Auxin is a key regulator of plant growth and development, but the causal relationship between hormone transport and root responses remains unresolved. Here we describe auxin uptake, together with early steps in signaling, in Arabidopsis root hairs. Using intracellular microelectrodes we show membrane depolarization, in response to IAA in a concentration- and pH-dependent manner. This depolarization is strongly impaired in aux1 mutants, indicating that AUX1 is the major transporter for auxin uptake in root hairs. Local intracellular auxin application triggers Ca 2+ signals that propagate as long-distance waves between root cells and modulate their auxin responses. AUX1-mediated IAA transport, as well as IAA - triggered calcium signals, are blocked by treatment with the SCF TIR1/AFB - inhibitor auxinole. Further, they are strongly reduced in the tir1afb2afb3 and the cngc14 mutant. Our study reveals that the AUX1 transporter, the SCF TIR1/AFB receptor and the CNGC14 Ca 2+ channel, mediate fast auxin signaling in roots. |
