title: Class I TCP-DELLA interactions in inflorescence shoot apex determine plant height.
abstract: Regulation of plant height, one of the most important agronomic traits, is the focus of intensive research for improving crop performance. Stem elongation takes place as a result of repeated cell divisions and subsequent elongation of cells produced by apical and intercalary meristems. The gibberellin (GA) phytohormones have long been known to control stem and internodal elongation by stimulating the degradation of nuclear growth-repressing DELLA proteins; however, the mechanism allowing GA-responsive growth is only slowly emerging. Here, we show that DELLAs directly regulate the activity of the plant-specific class I TCP transcription factor family, key regulators of cell proliferation. Our results demonstrate that class I TCP factors directly bind the promoters of core cell-cycle genes in Arabidopsis inflorescence shoot apices while DELLAs block TCP function by binding to their DNA-recognition domain. GAs antagonize such repression by promoting DELLA destruction and therefore cause a concomitant accumulation of TCP factors on promoters of cell-cycle genes. Consistent with this model, the quadruple mutant tcp8 tcp14 tcp15 tcp22 exhibits severe dwarfism and reduced responsiveness to GA action. Altogether, we conclude that GA-regulated DELLA-TCP interactions in inflorescence shoot apex provide a novel mechanism to control plant height.
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Davière
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Wild
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Regnault
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Baumberger
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Herfried
authors.initials: H
authors.lastname: Eisler
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France; Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/SupAgro/UM2, 34060 Montpellier, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Genschik
authors.affiliation: Institut de Biologie Moléculaire des Plantes, UPR2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France. Electronic address: patrick.achard@ibmp-cnrs.unistra.fr.
authors.forename: Patrick
authors.initials: P
authors.lastname: Achard
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism; D056626:Inflorescence / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005875:Gibberellins; D010937:Plant Growth Regulators; D014157:Transcription Factors