title: Transcriptomic response of Manduca sexta immune tissues to parasitization by the bracovirus associated wasp Cotesia congregata.
abstract: During oviposition, Cotesia congregata parasitoid wasps inject into their host, Manduca sexta, some biological factors such as venom, ovarian fluid and a symbiotic polydnavirus (PDV) named Cotesia congregata bracovirus (CcBV). During parasitism, complex interactions occur between wasp-derived factors and host targets that lead to important modifications in host physiology. In particular, the immune response leading to wasp egg encapsulation is inhibited allowing wasp survival. To date, the regulation of host genes during the interaction had only been studied for a limited number of genes. In this study, we analysed the global impact of parasitism on host gene regulation 24 h post oviposition by high throughput 454 transcriptomic analyses of two tissues known to be involved in the host immune response (hemocytes and fat body). To identify specific effects of parasitism on host transcription at this time point, transcriptomes were obtained from non-treated and parasitized larvae, and also from larvae injected with heat-killed bacteria and double stimulated larvae that were parasitized prior to bacterial challenge. Results showed that, immune challenge by bacteria leads to induction of certain antimicrobial peptide (AMP) genes in M. sexta larvae whether they were parasitized or not prior to bacterial challenge. These results show that at 24 h post oviposition pathways leading to expression of AMP genes are not all inactivated suggesting wasps are in an antiseptic environment. In contrast, at this time point genes involved in phenoloxidase activation and cellular immune responses were globally down-regulated after parasitism in accordance with the observed inhibition of wasp egg encapsulation.
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, UFR Sciences et Techniques, Université François-Rabelais, Tours, France.
authors.forename: Germain
authors.initials: G
authors.lastname: Chevignon
authors.affiliation: Department of Environment and Agrobiotechnologies Centre de Recherche Public - Gabriel Lippmann, Belvaux, Luxembourg.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Cambier
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, Genoscope (Centre National de Séquençage), Evry, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Da Silva
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, Genoscope (Centre National de Séquençage), Evry, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Poulain
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, UFR Sciences et Techniques, Université François-Rabelais, Tours, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Drezen
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, UFR Sciences et Techniques, Université François-Rabelais, Tours, France. Electronic address: elisabeth.huguet@univ-tours.fr.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Huguet
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, UFR Sciences et Techniques, Université François-Rabelais, Tours, France.
authors.forename: Sébastien J M
authors.initials: SJ
authors.lastname: Moreau
mesh_terms: D000818:Animals; D005216:Fat Body / Q000276:immunology / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism; D006790:Host-Parasite Interactions; D019476:Insect Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007814:Larva / Q000276:immunology / Q000469:parasitology / Q000821:virology; D018402:Manduca / Q000235:genetics / Q000276:immunology* / Q000469:parasitology* / Q000821:virology; D018071:Polydnaviridae / Q000276:immunology*; D059467:Transcriptome; D014863:Wasps / Q000502:physiology* / Q000821:virology
chemical_list: D019476:Insect Proteins
keywords: 454 sequencing; Antimicrobial peptide; Innate immunity; Manduca sexta; Parasitoid; Polydnavirus; Transcriptome