Mechanical induction of lateral root initiation in Arabidopsis thaliana.
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.
Ditengou
Franck Anicet
FA
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
Teale
William D
WD
Kochersperger
Philip
P
Flittner
Karl Andreas
KA
Kneuper
Irina
I
van der Graaff
Eric
E
Nziengui
Hugues
H
Pinosa
Francesco
F
Li
Xugang
X
Nitschke
Roland
R
Laux
Thomas
T
Palme
Klaus
K
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
D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis; D010937:Plant Growth Regulators; D011993:Recombinant Fusion Proteins