Transinfection of Culicoides sonorensis biting midge cell lines with Wolbachia pipientis

Authors: GHOSH, ARNAB - Texas Tech University; Jasperson, Dane; Cohnstaedt, Lee; BRELSFOARD, COREY - Texas Tech University

Submitted to: Vector-Borne and Zoonotic Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2019
Publication Date: 10/15/2019
Citation: Ghosh, A., Jasperson, D.C., Cohnstaedt, L.W., Brelsfoard, C. 2019. Transinfection of Culicoides sonorensis biting midge cell lines with Wolbachia pipientis. Vector-Borne and Zoonotic Diseases. 12:483. https://doi.org/10.1186/s13071-019-3716-0.
DOI: https://doi.org/10.1186/s13071-019-3716-0

Interpretive Summary: Biting midges can transmit various pathogens of veterinary importance. Reducing the biting midge populations or the contact between insects and animals will reduce pathogen transmission. Endosymbionts or organisms within the biting midges can be used as an alternative to pest control. This type of Wolbachia driven pest control has worked well with mosquitoes and this is the first reports of intentional infection of the symbiont into biting midges for the purpose of pathogen reduction or pest control. Successful introduction resulted in persistent infection of the biting midge cell lines and an increase in the immune response. Suggesting that the Wolbachia infection may be useful for reducing biting midge populations or reducing pathogen transmission.

Technical Abstract: Background: Biting midges of the genus Culicoides vector multiple veterinary pathogens and are difficult to control. Endosymbionts particularly Wolbachia pipientis may offer an alternative to control populations of Culicoides and/or impact disease transmission in the form of population suppression or replacement strategies. Methods: Culicoides sonorensis cell lines were transfected with a Wolbachia infection using a modified shell vial technique. Infections were confirmed using PCR and cell localization using fluorescent in situ hybridization (FISH). The stability of Wolbachia infections and density was determined by qPCR. qPCR was also used to examine immune genes in the IMD, Toll, and JACK/STAT pathways to determine if Wolbachia were associated with an immune response in infected cells. Results: Here we have transfected two Culicoides sonorensis cell lines (W3 and W8) with a Wolbachia infection (walbB) from donor Ae. albopictus Aa23 cells. PCR and FISH show the presence of Wolbachia infections in both C. sonorensis cell lines. Infection densities were higher in the W8 cell lines when compared to W3. In stably infected cells, genes in the immune Toll, IMD, and JAK/STAT pathways were upregulated, along with Attacin and an Attacin-like anti-microbial peptides. Conclusion: The successful introduction of Wolbachia infections in C. sonorensis cell lines and the upregulation of immune genes, suggest the utility of using Wolbachia for a population replacement and/or population suppression approach to limit the transmission of C. sonorensis vectored diseases. Results support the further investigation of Wolbachia induced pathogen inhibitory effects in Wolbachia infected C. sonorensis cell lines and the introduction of Wolbachia into C. sonorensis adults via embryonic microinjection to examine for reproductive phenotypes and host fitness effects of a novel Wolbachia infection.