Host aphid immunosuppression by Aphidius ervi venom

<p>Dataset referred to the manuscript:&nbsp;</p> <p><span><span><span><strong>Host aphid immunosuppression by </strong></span></span></span><span><span><span><em><strong>Aphidius</strong></em></span></span></span><span><span><span><strong> </strong></span></span></span><span><span><span><em><strong>ervi</strong></em></span></span></span><span><span><span><strong> venom</strong></span></span></span></p> <p><span><span><strong>Elia Russo</strong></span></span><span>^{<span><strong>1&sect;</strong></span>}</span><span><span><strong>, Andrea Becchimanzi</strong></span></span><span>^{<span><strong>1,2&sect;</strong></span>}</span><span><span><strong>, Giulia Magoga</strong></span></span><span>^{<span><strong>1</strong></span>}</span><span><span><strong>, Matteo Montagna</strong></span></span><span>^{<span><strong>1,2</strong></span>}</span><span><span><strong>, Ilaria Di Lelio</strong></span></span><span>^{<span><strong>1,2</strong></span>}</span><span><span><strong>* &amp; Francesco Pennacchio</strong></span></span><span>^{<span><strong>1,2</strong></span>}</span><span><span><strong>*</strong></span></span></p> <p>&nbsp;</p> <p>^{<span>1</span>}<span>University of Naples &lsquo;Federico II&rsquo; - Department of Agricultural Sciences, Naples, Italy, and </span>^{<span>2</span>}<span>BAT Center - Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples &lsquo;Federico II&rsquo;, Naples, Italy</span></p> <p>&nbsp;</p> <p><span><span><strong>bstract </strong></span></span></p> <p><span><span>The host immunosuppression by parasitic wasps is an important component of the host regulation strategy. The venom injected at the oviposition is one of the key-factors involved in this host alteration and, in some parasitoids, its immunosuppressive role is complemented by wasp&rsquo;s symbionts. Most studies in this research area are related to hosts belonging to Lepidoptera and Diptera, for which a strong immune response is observed, whereas little is known for hemimetabolous host species, characterized by apparently much weaker defense barriers. To fill this research gap, here we focus on the host&ndash;parasitoid system </span></span><span><span><em>Acyrthosiphon pisum</em></span></span><span><span> </span></span><span>(Harris) </span><span><span>(Hemiptera: Aphididae) &ndash; </span></span><span><span><em>Aphidius ervi</em></span></span><span><span> Haliday (Hymenoptera: Braconidae). We functionally characterized </span></span><span><span>a serine</span></span><span><span> protease homolog (</span></span><span><span><em>Ae</em></span></span><span><span>SPH) protein </span></span><span><span>in vivo, </span></span><span><span>identified in the venom of the aphid endoparasitoid </span></span><span><span><em>A. ervi</em></span></span><span><span>, generating </span></span><span><span><em>Ae</em></span></span><span><span>SPH-depleted female wasps by RNA interference and evaluating their capacity to successfully parasitize the host. Parasitism success rate was negatively affected by </span></span><span><span><em>Ae</em></span></span><span><span>SPH knockdown and associated with an increased phenoloxidase (PO) cascade activation in aphids, scored by measuring PO enzymatic activity and the expression of</span></span><span><span><em> phenoloxidase activating factor 2</em></span></span><span><span>, a</span></span><span><span> proPO-activating gene upregulated in response to </span></span><span><span><em>A. ervi</em></span></span><span><span> parasitism. Our results indicate that </span></span><span><span><em>Ae</em></span></span><span><span>SPH contributes to parasitism success by inhibiting the melanization response of the host, which is therefore an important component of the defense barriers involved in the parasitoid egg suppression. The undergoing studies on other virulence factors in </span></span><span><span><em>A. ervi</em></span></span><span><span> venom will allow to further characterize the immunosuppression strategy and its possible broader role in the host regulation through its action on aphid symbiont development. </span></span></p>