Insect host-parasitoid systems are examples of fascinating and complex interactions. Parasitoids have adapted to their respective hosts by developing several strategies ensuring the success of parasitism, providing physiological alterations and overcoming the immune response of their host. Maternal factors (venom, calyx fluid with or without polydnaviruses, and ovarian proteins), introduced into the host by the female wasps during egg deposition together with embryonic factor (teratocytes), play a key role in host regulation and immune suppression. Teratocytes are specialized cells deriving from the dissociation of the membrane surrounding the parasitoid embryo(serosa), and are released in the host haemocoel when the parasitoid egg hatches. They release several molecules impacting physiology, development and nutritional suitability of the host. To date only a single protein (a putative chitinase) has been identified in T. nigriceps teratocytes. Here, we use high-throughput RNA sequencing (RNA-Seq) to generate a de novo transcriptome of T. nigriceps teratocytes. RNA-Seq data assembly resulted in 24,569 contigs which were subsequently annotated using the BLASTx algorithm against the NR database and further functionally analysed using the Blast2GO software. The distribution of the species associated with top BLAST hits shows that a high proportion of genes in the T. nigriceps teratocyte transcriptome is most similar to genes belonging to different parasitoid wasp species, in particular, to Microplitis demolitor. Among the predicted proteins identified, several are potentially involved in host immunosuppression such as ovalbumin-related X-like proteins, serpin proteins, chitinases and Rho GAP proteins. Moreover, similar to the transcriptomic analysis of M. demolitor teratocytes, we identified putative antimicrobial peptides. These preliminary results led us to hypothesize that teratocytes are not only responsible for host immunosuppression but at the same time could prevent host infection by pathogen intruders, supporting the immunosuppressed host through the production of parasitoid-derived AMPs.

Generation and analysis of a comprehensive Toxoneuron nigriceps teratocyte transcriptome

Rosanna Salvia;Andrea Scala;Marisa Nardiello;Donatella Farina;Sabino Aurelio Bufo;Patrizia Falabella
2018

Abstract

Insect host-parasitoid systems are examples of fascinating and complex interactions. Parasitoids have adapted to their respective hosts by developing several strategies ensuring the success of parasitism, providing physiological alterations and overcoming the immune response of their host. Maternal factors (venom, calyx fluid with or without polydnaviruses, and ovarian proteins), introduced into the host by the female wasps during egg deposition together with embryonic factor (teratocytes), play a key role in host regulation and immune suppression. Teratocytes are specialized cells deriving from the dissociation of the membrane surrounding the parasitoid embryo(serosa), and are released in the host haemocoel when the parasitoid egg hatches. They release several molecules impacting physiology, development and nutritional suitability of the host. To date only a single protein (a putative chitinase) has been identified in T. nigriceps teratocytes. Here, we use high-throughput RNA sequencing (RNA-Seq) to generate a de novo transcriptome of T. nigriceps teratocytes. RNA-Seq data assembly resulted in 24,569 contigs which were subsequently annotated using the BLASTx algorithm against the NR database and further functionally analysed using the Blast2GO software. The distribution of the species associated with top BLAST hits shows that a high proportion of genes in the T. nigriceps teratocyte transcriptome is most similar to genes belonging to different parasitoid wasp species, in particular, to Microplitis demolitor. Among the predicted proteins identified, several are potentially involved in host immunosuppression such as ovalbumin-related X-like proteins, serpin proteins, chitinases and Rho GAP proteins. Moreover, similar to the transcriptomic analysis of M. demolitor teratocytes, we identified putative antimicrobial peptides. These preliminary results led us to hypothesize that teratocytes are not only responsible for host immunosuppression but at the same time could prevent host infection by pathogen intruders, supporting the immunosuppressed host through the production of parasitoid-derived AMPs.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11563/134417
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