title: Mechanical induction of lateral root initiation in Arabidopsis thaliana.
abstract: Lateral roots are initiated postembryonically in response to environmental cues, enabling plants to explore efficiently their underground environment. However, the mechanisms by which the environment determines the position of lateral root formation are unknown. In this study, we demonstrate that in Arabidopsis thaliana lateral root initiation can be induced mechanically by either gravitropic curvature or by the transient bending of a root by hand. The plant hormone auxin accumulates at the site of lateral root induction before a primordium starts to form. Here we describe a subcellular relocalization of PIN1, an auxin transport protein, in a single protoxylem cell in response to gravitropic curvature. This relocalization precedes auxin-dependent gene transcription at the site of a new primordium. Auxin-dependent nuclear signaling is necessary for lateral root formation; arf7/19 double knock-out mutants normally form no lateral roots but do so upon bending when the root tip is removed. Signaling through arf7/19 can therefore be bypassed by root bending. These data support a model in which a root-tip-derived signal acts on downstream signaling molecules that specify lateral root identity.
authors.affiliation: Institutes of Biology II and Biology III, Faculty of Biology, Albert-Ludwigs-Universität of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany. franck.ditengou@biologie.uni-freiburg.de
authors.forename: Franck Anicet
authors.initials: FA
authors.lastname: Ditengou
authors.forename: William D
authors.initials: WD
authors.lastname: Teale
authors.forename: Philip
authors.initials: P
authors.lastname: Kochersperger
authors.forename: Karl Andreas
authors.initials: KA
authors.lastname: Flittner
authors.forename: Irina
authors.initials: I
authors.lastname: Kneuper
authors.forename: Eric
authors.initials: E
authors.lastname: van der Graaff
authors.forename: Hugues
authors.initials: H
authors.lastname: Nziengui
authors.forename: Francesco
authors.initials: F
authors.lastname: Pinosa
authors.forename: Xugang
authors.initials: X
authors.lastname: Li
authors.forename: Roland
authors.initials: R
authors.lastname: Nitschke
authors.forename: Thomas
authors.initials: T
authors.lastname: Laux
authors.forename: Klaus
authors.initials: K
authors.lastname: Palme
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018522:Gravitropism; D007210:Indoleacetic Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000254:growth & development* / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism; D018520:Plant Shoots / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013314:Stress, Mechanical
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis; D010937:Plant Growth Regulators; D011993:Recombinant Fusion Proteins