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The team aims at deciphering the physiological and molecular bases of the specificity of multitrophic interactions involving insect hosts, associated bacterial symbionts, and parasitoid wasps.  
Our research projects focus for instance on: the insect immune response and how it is possibly modulated by bacterial symbionts, the evolution of virulence factors from venom of Hymenopteran parasitoids, or the role played by extra-cellular vesicles in the transfer of information between host and parasitoid species. 

Scientific context

Understanding the mechanisms sustaining the outcome and specificity of interactions between species is a main goal of ongoing researches in biology. Results may indeed open new research areas and they already have practical implications for animal and plant health. In this context, our work aim at understanding the molecular and biochemical mechanisms involved in eukaryote-eukaryote parasitic interactions (insect host - insect parasitoid) as well as eukaryote-prokaryote (insect - bacteria) interactions, with the final objective of "deciphering" multitrophic relationships. We thus perform an integrative approach with a strong background of evolutionary biology. 

General theme and objectives

Main research objectives are :

• understand the mechanisms allowing host shift in parasitoid species by characterizing the key physiological factors involved in host specificity : e.g. parasitoid virulence factors and their targets in the host, host resistance mechanisms. We also focus on the mechanisms at the origin of the observed variability of venom virulence factors in parasitoids and perform experimental selection approaches to assess whether this factors can rapidly evolve. 
• understand how primary and secondary symbionts interfere with the immune competence of phloemophagous insects and their immune response to parasitoid wasps. This project participated in the current research focus on the link between immunity, metabolism, and symbiosis. 
• decipher sex determination mechanisms in endoparasitoids (haplo-diploid organisms) - Secondary project

Biological models

• Insect hosts : Drosophila spp (including D. melanogaster and the invasive pest D. suzukii), Acyrthosiphon pisum (pea aphid), Ceratitis capitata
• Insect parasitoids : Leptopilina spp (parasitoids of Drosophila spp.), Asobara spp (parasitoids of Drosophila spp.), Venturia canescens (parasitoid of Lepidoptera), Psyttalia spp. (parasitoids of Diptera, olive fly and fruit flies)
• Bacterial symbionts (primary and secondary symbionts) of Acyrthosiphon pisum

Originality of the scientific project

Multidisciplinary approaches – Integration of different trophic levels

Current research projects

Interactions between phytophagous insects (Diptera) and parasitoid wasps

• Understand the bases of the intra- and interspecific variation of virulence in endoparasitoid wasps
  • assessment of the level of inter-individual variation of venom proteins and development of a method allowing global analysis of venom and associated statistical analyses
  • analysis of the importance of gene duplications and changes in the regulation of gene expression in the striking variation of venom composition.
  • development of RNAi to target venom proteins of endoparasitoid wasps (Colinet et al., 2014)
• Understand the nature and decipher the role of venosomes, extracellular vesicles produced in the venom of some parasitoid species 

Interactions between phytophagous insects (Aphids), symbionts and parasitoid wasps

• Improve our knowledge of the cellular immunity of aphids
• Understand the variation in immune components of aphids associated with the presence of different symbionts/symbiont strains
• Assess the possible role of symbionts in the outcome of immune and physiological interactions between aphids and their parasitoid wasps

Application

Development of new methods for the biological control of insect pests (aphids, Diptera) - Development of methods/markers for quality control of parasitoid auxiliaries

Research networks and partnersPartenariat scientifique

• Networks : GDR 2153 (Evolution of parasitic interactions and role of symbiotic microorganisms), REID (Réseau d’Étude des Interactions Durables), BAPOA (Adaptative biology of aphids and associated organisms), Biologie Adaptative des Pucerons et des Organismes associés), GDR Invabio (Biological Invasions)
• National : dans le cadre des ANR Paratoxose, Climevol, Sextinction, ImBio, IMetSym, de projets Région et INRA SPE et du Labex Signalife (http://signalife.unice.fr/)
• International : University of Loyola (Chicago), University of Naples, partners of the european project DROPSA