Auxin-dependent regulation of lateral root positioning in the basal meristem of Arabidopsis.
In plants, the developmental mechanisms that regulate the positioning of lateral organs along the primary root are currently unknown. We present evidence on how lateral root initiation is controlled in a spatiotemporal manner in the model plant Arabidopsis thaliana. First, lateral roots are spaced along the main axis in a regular left-right alternating pattern that correlates with gravity-induced waving and depends on AUX1, an auxin influx carrier essential for gravitropic response. Second, we found evidence that the priming of pericycle cells for lateral root initiation might take place in the basal meristem, correlating with elevated auxin sensitivity in this part of the root. This local auxin responsiveness oscillates with peaks of expression at regular intervals of 15 hours. Each peak in the auxin-reporter maximum correlates with the formation of a consecutive lateral root. Third, auxin signaling in the basal meristem triggers pericycle cells for lateral root initiation prior to the action of INDOLE-3-ACETIC ACID14 (SOLITARY ROOT).
De Smet
Ive
I
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, Technologiepark 927, B-9052 Gent, Belgium.
Tetsumura
Takuya
T
De Rybel
Bert
B
Frei dit Frey
Nicolas
N
Laplaze
Laurent
L
Casimiro
Ilda
I
Swarup
Ranjan
R
Naudts
Mirande
M
Vanneste
Steffen
S
Audenaert
Dominique
D
Inzé
Dirk
D
Bennett
Malcolm J
MJ
Beeckman
Tom
T
D017360:Arabidopsis / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000502:physiology*; D001683:Biological Clocks; D018522:Gravitropism; D007210:Indoleacetic Acids / Q000494:pharmacology*; D018519:Meristem / Q000502:physiology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000254:growth & development*
C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; C030737:indoleacetic acid