title: TIR1/AFB-Aux/IAA auxin perception mediates rapid cell wall acidification and growth of Arabidopsis hypocotyls.
abstract: Despite being composed of immobile cells, plants reorient along directional stimuli. The hormone auxin is redistributed in stimulated organs leading to differential growth and bending. Auxin application triggers rapid cell wall acidification and elongation of aerial organs of plants, but the molecular players mediating these effects are still controversial. Here we use genetically-encoded pH and auxin signaling sensors, pharmacological and genetic manipulations available for Arabidopsis etiolated hypocotyls to clarify how auxin is perceived and the downstream growth executed. We show that auxin-induced acidification occurs by local activation of H+-ATPases, which in the context of gravity response is restricted to the lower organ side. This auxin-stimulated acidification and growth require TIR1/AFB-Aux/IAA nuclear auxin perception. In addition, auxin-induced gene transcription and specifically SAUR proteins are crucial downstream mediators of this growth. Our study provides strong experimental support for the acid growth theory and clarified the contribution of the upstream auxin perception mechanisms.
authors.affiliation: Institute of Science and Technology Austria, Klosterneuburg, Austria.
authors.forename: Matyáš
authors.initials: M
authors.lastname: Fendrych
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, INRA - Centre de Versailles-Grignon, Saclay Plant Science, Versailles, France.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Leung
authors.affiliation: Institute of Science and Technology Austria, Klosterneuburg, Austria.
authors.forename: Jiří
authors.identifier: 0000-0002-8302-7596
authors.initials: J
authors.lastname: Friml
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D004789:Enzyme Activation; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D018546:Hypocotyl / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000187:drug effects / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D011956:Receptors, Cell Surface; C000623004:SAUR19 protein, Arabidopsis; C501405:TIR1 protein, Arabidopsis; D006180:Proton-Translocating ATPases
keywords: A. thaliana; auxin; cell biology; cell wall; growth; hypocotyl; plant biology