You are here : Home > Research > Luminy Plant Genetics and Biop ... > Research topics > Regulation of plant growth by energy signaling pathways

Regulation of plant growth by energy signaling pathways

Published on 25 February 2019

​​Scientists involved : Benoît Menand, Marie-Hélène Montané, Christophe Robaglia, Cécile Lecampion, Annemarie Matthes, Seddik Harchouni, Adam Barrada, Rikhia Majumder

Collaborations : Christian Meyer (INRA, IJPB, Versailles), Lyubov Ryabova (CNRS, IBMP Strasbourg), Carole Caranta (INRA Avignon), IMM proteomic platform http://www.imm.cnrs.fr/proteomique

 

​Project

At the whole plant level photosynthetic energy status is connected with growth control and with responses to external stresses (drought, mineral deprivation, pathogen attacks, etc.). Growth control is largely mediated through the global and specific activity of the protein synthesis machinery and through regulation of the cell cycle. Some mechanisms controlling growth are very ancient and phylogenetically well conserved. However, it is largely unknown how these mechanisms have become integrated with the energy resources specific to photosynthetic organisms, and/or to what extent they played a decisive role during evolution and the colonization of land by plants. One of the major conserved eukaryotic signaling pathways that tunes growth and metabolism is the TOR signaling pathway (Fig. 1). The TOR (Target Of Rapamycin) protein is a large phosphatidylinositol-3 kinase-like protein kinase (PIKK) that is conserved in most eukaryotes.

 

We study the TOR pathway in flowering plants such as Arabidopsis thaliana, but also in the moss Physcomitrella patens.  Because P. patens belongs to a basal group of land plants it will help us identify elements of the TOR pathway that are conserved in photosynthetic eukaryotes. Unlike other model plants P. patens is also amenable to gene targeting, making it a powerful model system for studying signaling system components. We are also using P. patens to investigate the relationship between two major energy signaling pathways in the cytosol and the chloroplast.

 

We are developing pharmacological, genetic, cellular biology and proteomic approaches to study the TOR signaling pathway in plants. The pharmacological strategy consists in using ATP-competitive inhibitors (called asTORis for active site TOR inhibitors), recently developed for the human TOR kinase, on plants (Montané and Menand 2013, Fig 2.). Using these new pharmacological tools, we have shown that plant TOR regulates growth by controlling the number of proliferating meristem cells (Fig. 3). We are currently using mutants in combination with asTORis to identify components of the plant TOR pathway at the tissue and organ level. We are also searching for new targets of plant TOR using proteomics. 


 

 
 

Main targets and functions of the TOR/S6K signaling pathway in mammals and plants.: B. Menand/CNRS

Dose-dependent inhibition of plant growth by the active site TOR inhibitor AZD-8055. Arabidopsis thaliana plants were grown for 3 days without drug or DMSO, transferred to drug-containing plates and grown for 6 days. Pictures of vertically grown whole plants (upper panel) and of aerial part (lower panel) on AZD-8055.

B. Menand/CNRS and M.-H. Montané/CEA, J. Exp. Bot. 2013

 
 
Active site TOR inhibitor reduces the size of the meristem and the proliferation zone in Arabidopsis roots but not the G2 phase of the cell cycle. DIC microscopy pictures of the root tip with the meristematic zone delimited by arrows. CYCB1;1::GUS expression (in blue) marks cells in the G2 phase of the cell cycle.

B. Menand/CNRS and M.-H. Montané/CEA, J. Exp. Bot. 2013


​Main publications in HAL repository

  • Montané M-H and Menand B (2013) ATP-competitive mTOR kinase inhibitors delay plant growth by triggering early differentiation of meristematic cells but no developmental patterning change. Journal of Experimental Botany, 64 (14): 4361-4374.
  • Dobrenel T, Marchive C, Azzopardi M, Clément G, Moreau M, Sormani R, Robaglia C, Meyer C (2013) Sugar metabolism and the plant target of rapamycin kinase: a sweet operaTOR? Front Plant Sci. 4:93. doi: 10.3389/fpls.2013.00093.
  • Moreau M, Azzopardi M, Clement G, Dobrenel T, Marchive C, Renne C, Martin-Magniette Ml, Taconnat L, Renou JP, Robaglia C, Meyer C (2012) Mutations in the Arabidopsis Homolog of LST8/G beta L, a Partner of the Target of Rapamycin Kinase, Impair Plant Growth, Flowering, and Metabolic Adaptation to Long Days. Plant Cell 24(2): 463-481
  • Schepetilnikov M, Kobayashi K, Geldreich A, Caranta C, Robaglia C, Keller M, Ryabova LA. (2011). Viral factor TAV recruits TOR/S6K1 signalling to activate reinitiation after long ORF translation. EMBO Journal doi:10.1038/emboj.2011.39.
  • Deprost D, Yao L, Sormani R, Moreau M, Leterreux G, Nicolai M, Bedu M, Robaglia C And Meyer C (2007) The Arabidopsis TOR kinase links plant growth, yield, stress resistance and mRNA translation. EMBO Rep. 8(9):864-70.
  • Menand B, Desnos T, Nussaume L, Berger F, Bouchez D, Meyer C &  Robaglia C (2002) Expression and disruption of the Arabidopsis TOR (Target of Rapamycin) gene. Proceedings of the National Academy of Sciences USA 99, 6422-6427.