title: Lateral root emergence in Arabidopsis is dependent on transcription factor LBD29 regulation of auxin influx carrier LAX3.
abstract: Lateral root primordia (LRP) originate from pericycle stem cells located deep within parental root tissues. LRP emerge through overlying root tissues by inducing auxin-dependent cell separation and hydraulic changes in adjacent cells. The auxin-inducible auxin influx carrier LAX3 plays a key role concentrating this signal in cells overlying LRP. Delimiting LAX3 expression to two adjacent cell files overlying new LRP is crucial to ensure that auxin-regulated cell separation occurs solely along their shared walls. Multiscale modeling has predicted that this highly focused pattern of expression requires auxin to sequentially induce auxin efflux and influx carriers PIN3 and LAX3, respectively. Consistent with model predictions, we report that auxin-inducible LAX3 expression is regulated indirectly by AUXIN RESPONSE FACTOR 7 (ARF7). Yeast one-hybrid screens revealed that the LAX3 promoter is bound by the transcription factor LBD29, which is a direct target for regulation by ARF7. Disrupting auxin-inducible LBD29 expression or expressing an LBD29-SRDX transcriptional repressor phenocopied the lax3 mutant, resulting in delayed lateral root emergence. We conclude that sequential LBD29 and LAX3 induction by auxin is required to coordinate cell separation and organ emergence.
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors: Silvana
authors: S
authors: Porco
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK Laboratoire Reproduction et Développement des Plantes, Univ. Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342 Lyon, France.
authors: Antoine
authors: A
authors: Larrieu
authors: Molecular Genetics, Department of Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, The Netherlands.
authors: Yujuan
authors: Y
authors: Du
authors: Department of Plant Biology and Genome Center, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
authors: Allison
authors: A
authors: Gaudinier
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK Department of Biology, Graduate School of Science, Kobe University, Kobe 657-8501, Japan.
authors: Tatsuaki
authors: T
authors: Goh
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors: Kamal
authors: K
authors: Swarup
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors: Ranjan
authors: R
authors: Swarup
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors: Britta
authors: B
authors: Kuempers
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors: Anthony
authors: A
authors: Bishopp
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK Institute of Plant Sciences, 21 Altenbergrain, Bern 3006, Switzerland.
authors: Julien
authors: J
authors: Lavenus
authors: Departamento Anatomia, Biologia Celular Y Zoologia, Facultad de Ciencias, Universidad de Extremadura, Badajoz 06006, Spain.
authors: Ilda
authors: I
authors: Casimiro
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK.
authors: Kristine
authors: K
authors: Hill
authors: Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria.
authors: Eva
authors: E
authors: Benkova
authors: Department of Biology, Graduate School of Science, Kobe University, Kobe 657-8501, Japan.
authors: Hidehiro
authors: H
authors: Fukaki
authors: Department of Plant Biology and Genome Center, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
authors: Siobhan M
authors: SM
authors: Brady
authors: Molecular Genetics, Department of Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, The Netherlands.
authors: Ben
authors: B
authors: Scheres
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK Centre National de la Recherche Scientifique, Biochimie et Physiologie Moléculaire des Plantes, Montpellier SupAgro, 2 Place Pierre Viala, Montpellier 34060, France malcolm.bennett@nottingham.ac.uk benjamin.peret@supagro.fr.
authors: Benjamin
authors: 0000-0003-1336-0796
authors: B
authors: Péret
authors: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham LE12 5RD, UK malcolm.bennett@nottingham.ac.uk benjamin.peret@supagro.fr.
authors: Malcolm J
authors: 0000-0003-0475-390X
authors: MJ
authors: Bennett
mesh_terms: D017360:Arabidopsis / Q000378:metabolism* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism* / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C531125:LAX3 protein, Arabidopsis; C583247:LBD29 protein, Arabidopsis; D026901:Membrane Transport Proteins; D014157:Transcription Factors
keywords: Arabidopsis; Auxin; LBD29; Lateral root emergence; Root development