title: Auxin reflux between the endodermis and pericycle promotes lateral root initiation.
abstract: Lateral root (LR) formation is initiated when pericycle cells accumulate auxin, thereby acquiring founder cell (FC) status and triggering asymmetric cell divisions, giving rise to a new primordium. How this auxin maximum in pericycle cells builds up and remains focused is not understood. We report that the endodermis plays an active role in the regulation of auxin accumulation and is instructive for FCs to progress during the LR initiation (LRI) phase. We describe the functional importance of a PIN3 (PIN-formed) auxin efflux carrier-dependent hormone reflux pathway between overlaying endodermal and pericycle FCs. Disrupting this reflux pathway causes dramatic defects in the progress of FCs towards the next initiation phase. Our data identify an unexpected regulatory function for the endodermis in LRI as part of the fine-tuning mechanism that appears to act as a check point in LR organogenesis after FCs are specified.
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Marhavý
authors.forename: Marleen
authors.initials: M
authors.lastname: Vanstraelen
authors.forename: Bert
authors.initials: B
authors.lastname: De Rybel
authors.forename: Ding
authors.initials: D
authors.lastname: Zhaojun
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Bennett
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
authors.forename: Eva
authors.initials: E
authors.lastname: Benková
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060049:Asymmetric Cell Division; D001692:Biological Transport; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D009154:Mutation; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; C449300:PIN3 protein, Arabidopsis; C479554:PIN7 protein, Arabidopsis; D010937:Plant Growth Regulators; D011993:Recombinant Fusion Proteins; C034182:1-naphthaleneacetic acid