title: Israeli Acute Paralysis Virus Infection Leads to an Enhanced RNA Interference Response and Not Its Suppression in the Bumblebee Bombus terrestris.
abstract: RNA interference (RNAi) is the primary antiviral defense system in insects and its importance for pollinator health is indisputable. In this work, we examined the effect of Israeli acute paralysis virus (IAPV) infection on the RNAi process in the bumblebee,Bombus terrestris, and whether the presence of possible functional viral suppressors could alter the potency of the host's immune response. For this, a two-fold approach was used. Through a functional RNAi assay, we observed an enhancement of the RNAi system after IAPV infection instead of its suppression, despite only minimal upregulation of the genes involved in RNAi. Besides, the presence of the proposed suppressor 1A and the predicted OrfX protein in IAPV could not be confirmed using high definition mass spectrometry. In parallel, when bumblebees were infected with cricket paralysis virus (CrPV), known to encode a suppressor of RNAi, no increase in RNAi efficiency was seen. For both viruses, pre-infection with the one virus lead to a decreased replication of the other virus, indicating a major effect of competition. These results are compelling in the context ofDicistroviridaein multi-virus/multi-host networks as the effect of a viral infection on the RNAi machinery may influence subsequent virus infections.
authors.affiliation: Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium. kaat.cappelle@ugent.be.
authors.forename: Kaat
authors.initials: K
authors.lastname: Cappelle
authors.affiliation: Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium. guy.smagghe@ugent.be.
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium. maarten.dhaenens@ugent.be.
authors.forename: Maarten
authors.initials: M
authors.lastname: Dhaenens
authors.affiliation: Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium. ivan.meeus@ugent.be.
authors.forename: Ivan
authors.initials: I
authors.lastname: Meeus
mesh_terms: D000818:Animals; D001516:Bees / Q000276:immunology / Q000821:virology*; D056629:Dicistroviridae / Q000276:immunology* / Q000502:physiology*; D054884:Host-Pathogen Interactions; D034622:RNA Interference; D014762:Viral Interference; D014779:Virus Replication
keywords: Bombus terrestris; Israeli acute paralysis virus; RNA interference (RNAi); bee health; cricket paralysis virus; viral suppressors of RNAi