title: Auxin-dependent regulation of lateral root positioning in the basal meristem of Arabidopsis.
abstract: 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).
authors.affiliation: Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, Technologiepark 927, B-9052 Gent, Belgium.
authors.forename: Ive
authors.initials: I
authors.lastname: De Smet
authors.forename: Takuya
authors.initials: T
authors.lastname: Tetsumura
authors.forename: Bert
authors.initials: B
authors.lastname: De Rybel
authors.forename: Nicolas
authors.initials: N
authors.lastname: Frei dit Frey
authors.forename: Laurent
authors.initials: L
authors.lastname: Laplaze
authors.forename: Ilda
authors.initials: I
authors.lastname: Casimiro
authors.forename: Ranjan
authors.initials: R
authors.lastname: Swarup
authors.forename: Mirande
authors.initials: M
authors.lastname: Naudts
authors.forename: Steffen
authors.initials: S
authors.lastname: Vanneste
authors.forename: Dominique
authors.initials: D
authors.lastname: Audenaert
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Bennett
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
mesh_terms: 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*
chemical_list: C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; C030737:indoleacetic acid