Pathogen perception : RRS1, a resistance protein with unique features and PopP2, a bacterial effector targeting several plant proteins
RRS1-R, a gene conferring broad spectrum resistance to Rs, the causal agent of bacterial wilt, encodes a novel R protein combining domains found in plant TIR-NBS-LRR resistance proteins and a WRKY motif characteristic of some plant transcriptional factors. PopP2, a Rs type III effector is the avirulence protein matching RRS1-R. These two key elements have been used to decipher mechanisms underlying pathogen perception. The main goal of our work consists in (i) the identification of other components of the perception complex, (ii) the characterization of host components targeted by PopP2 acetyltransferase activity and (iii) the identification of RRS1-R target genes.
Plant disease: genes involved in plant development and susceptibility
Mutants affected in disease development in response to virulent strains of Rs were identified and correspond to the so-called CLAVATA genes. CLV1, an extracellular Leucine-Rich Repeat (LRR) receptor kinase and CLV2, a LRR protein without a kinase domain, are known to control the balance between meristem cell proliferation and differentiation. Using a combination of genetic, biochemical and cellular approaches, our goal is to analyze the mechanisms underlying the increased tolerance of the clv1 and clv2 mutants.
Contract ANR-PRCI “Nuclear Activities of DNA-Associated Immune Receptors (RADAR)”, 2015-2019, Coordinator: L. Deslandes, 280 k€ (collaboration with J. E. Parker and K. Niefind).
Contract IDEX-Emergence “Modulation of Chromatin Architecture by bacterial Effectors (MOCA)”, 2016-2018, Coordinator: L. Deslandes, 142 k€.
INRA SPE Department Scientific project –Amorçage “Identification des mécanismes de régulation épigénétique au sein des cellules en interaction avec deux bioagresseurs racinaires (INTACT)”, 2016-2018, Coordinator: Stéphanie JAUBERT-POSSAMAI, 40 k€.
INRA SPE Department Scientific project «Plant responses to multistresses: Study and modelling of plant immune response alteration at moderately high temperature », Coordinator R. Berthomé, 2014 –2015, 30 k€.
Contract ANR-JCJC “Identification of host components involved in a perception complex (PERCEPTome)”, 2010-2014, Coordinator: L. Deslandes, 230 k€.
FRAIB Research contact “Impact of a moderate increase of temperature on plant immune response to Ralstonia solanacearum:study of the calcium signaling pathway ”, Coordinators R. Berthomé/D. Aldon, 2014, 10 k€.
Our local collaborations involve Laurent Noel, LIPM (Xanthomonas/Arabidopsis interaction), Nemo Peeters/Fabienne Vailleau, LIPM (Ralstonia pathogenesis), Jean-Philippe Galaud, LRSV (Calmodulin and plant-pathogen interactions), Laurent Camborde, LRSV (Monitoring of protein-DNA associations) and Alain Jauneau/Cécile Pouzet (Plateforme Toulouse Réseau-Imagerie (TRI)).
At the national level, we are collaborating with H. Keller and B. Favery, ISA Sophia, (Susceptibility responses), Y. Couté/Alexandra Kraut, Plateforme d’analyses protéomiques, Plateforme Edyp-Grenoble (acetylation of host component), Alexandre Berr, IBMP Strasbourg (Epigenetic regulation of immune responses).
At the international level, we collaborate with Jane Parker (Max Planck Institute, Kôln) and Karsten Niefind (University of Köln) (ANR PRCI RADAR), Stefan Knapp (Oxford University), Hirofumi Yoshioka (Nagoya University), Gitta Coaker (UC Davis).