title: Regulation of plant growth and metabolism by the TOR kinase.
abstract: The TOR (target of rapamycin) kinase is present in nearly all eukaryotic organisms and regulates a wealth of biological processes collectively contributing to cell growth. The genome of the model plant Arabidopsis contains a single TOR gene and two RAPTOR (regulatory associated protein of TOR)/KOG1 (Kontroller of growth 1) and GβL/LST8 (G-protein β-subunit-like/lethal with Sec thirteen 8) genes but, in contrast with other organisms, plants appear to be resistant to rapamycin. Disruption of the RAPTOR1 and TOR genes in Arabidopsis results in an early arrest of embryo development. Plants that overexpress the TOR mRNA accumulate more leaf and root biomass, produce more seeds and are more resistant to stress. Conversely, the down-regulation of TOR by constitutive or inducible RNAi (RNA interference) leads to a reduced organ growth, to an early senescence and to severe transcriptomic and metabolic perturbations, including accumulation of sugars and amino acids. It thus seems that plant growth is correlated to the level of TOR expression. We have also investigated the effect of reduced TOR expression on tissue organization and cell division. We suggest that, like in other eukaryotes, the plant TOR kinase could be one of the main contributors to the link between environmental cues and growth processes.
authors.affiliation: Institut Jean-Pierre Bourgin (IJPB), UMR 1318 INRA AgroParisTech, 78026 Versailles Cedex, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dobrenel
authors.forename: Chloé
authors.initials: C
authors.lastname: Marchive
authors.forename: Rodnay
authors.initials: R
authors.lastname: Sormani
authors.forename: Manon
authors.initials: M
authors.lastname: Moreau
authors.forename: Milena
authors.initials: M
authors.lastname: Mozzo
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Montané
authors.forename: Benoît
authors.initials: B
authors.lastname: Menand
authors.forename: Christophe
authors.initials: C
authors.lastname: Robaglia
authors.forename: Christian
authors.initials: C
authors.lastname: Meyer
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006801:Humans; D008954:Models, Biological; D010802:Phylogeny; D063245:Plant Development; D010944:Plants / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*
chemical_list: D058570:TOR Serine-Threonine Kinases