title: Sequential induction of auxin efflux and influx carriers regulates lateral root emergence.
abstract: In Arabidopsis, lateral roots originate from pericycle cells deep within the primary root. New lateral root primordia (LRP) have to emerge through several overlaying tissues. Here, we report that auxin produced in new LRP is transported towards the outer tissues where it triggers cell separation by inducing both the auxin influx carrier LAX3 and cell-wall enzymes. LAX3 is expressed in just two cell files overlaying new LRP. To understand how this striking pattern of LAX3 expression is regulated, we developed a mathematical model that captures the network regulating its expression and auxin transport within realistic three-dimensional cell and tissue geometries. Our model revealed that, for the LAX3 spatial expression to be robust to natural variations in root tissue geometry, an efflux carrier is required--later identified to be PIN3. To prevent LAX3 from being transiently expressed in multiple cell files, PIN3 and LAX3 must be induced consecutively, which we later demonstrated to be the case. Our study exemplifies how mathematical models can be used to direct experiments to elucidate complex developmental processes.
authors.affiliation: 1] Centre for Plant Integrative Biology, University of Nottingham, Loughborough, UK [2] Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough, UK [3] Unité Mixte de Recherche 7265, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, Aix-Marseille Université, Laboratoire de Biologie du Développement des Plantes, Saint-Paul-lez-Durance, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Péret
authors.forename: Alistair M
authors.initials: AM
authors.lastname: Middleton
authors.forename: Andrew P
authors.initials: AP
authors.lastname: French
authors.forename: Antoine
authors.initials: A
authors.lastname: Larrieu
authors.forename: Anthony
authors.initials: A
authors.lastname: Bishopp
authors.forename: Maria
authors.initials: M
authors.lastname: Njo
authors.forename: Darren M
authors.initials: DM
authors.lastname: Wells
authors.forename: Silvana
authors.initials: S
authors.lastname: Porco
authors.forename: Nathan
authors.initials: N
authors.lastname: Mellor
authors.forename: Leah R
authors.initials: LR
authors.lastname: Band
authors.forename: Ilda
authors.initials: I
authors.lastname: Casimiro
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kleine-Vehn
authors.forename: Steffen
authors.initials: S
authors.lastname: Vanneste
authors.forename: Ilkka
authors.initials: I
authors.lastname: Sairanen
authors.forename: Romain
authors.initials: R
authors.lastname: Mallet
authors.forename: Göran
authors.initials: G
authors.lastname: Sandberg
authors.forename: Karin
authors.initials: K
authors.lastname: Ljung
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
authors.forename: Eva
authors.initials: E
authors.lastname: Benkova
authors.forename: Jiří
authors.initials: J
authors.lastname: Friml
authors.forename: Eric
authors.initials: E
authors.lastname: Kramer
authors.forename: John R
authors.initials: JR
authors.lastname: King
authors.forename: Ive
authors.initials: I
authors.lastname: De Smet
authors.forename: Tony
authors.initials: T
authors.lastname: Pridmore
authors.forename: Markus
authors.initials: M
authors.lastname: Owen
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Bennett
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008957:Models, Genetic; D009928:Organ Specificity; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C531125:LAX3 protein, Arabidopsis; D026901:Membrane Transport Proteins; C449300:PIN3 protein, Arabidopsis