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Updated: Apr 22, 2026
Chitosan/Interfering RNA Nanoparticle Mediated Gene Silencing in Disease Vector Mosquito Larvae
Published on: March 25, 2015
Inducing RNA interference in the arbovirus vector, Culicoides sonorensis
Abstract:
Biting midges in the genus Culicoides are important vectors of arboviral diseases, including epizootic haemorrhagic disease, bluetongue and most likely Schmallenberg, which cause significant economic burdens worldwide. Research on these vectors has been hindered by the lack of a sequenced genome, the difficulty of consistent culturing of certain species and the absence of molecular techniques such as RNA interference (RNAi). Here, we report the establishment of RNAi as a research tool for the adult midge, Culicoides sonorensis. Based on previous research and transcriptome analysis, which revealed putative small interfering RNA pathway member orthologues, we hypothesized that adult C. sonorensis midges have the molecular machinery needed to perform RNA silencing. Injection of control double-stranded RNA targeting green fluorescent protein (dsGFP), into the haemocoel of 2-3-day-old adult female midges resulted in survival curves that support virus transmission. dsRNA injection targeting the newly identified C. sonorensis inhibitor of apoptosis protein 1 (CsIAP1) orthologue resulted in a 40% decrease of transcript levels and 73% shorter median survivals as compared with dsGFP-injected controls. These results reveal the conserved function of IAP1. Importantly, they also demonstrate the feasibility of RNAi by dsRNA injection in adult midges, which will greatly facilitate studies of the underlying mechanisms of vector competence in C. sonorensis.
Insights
RNA interference (RNAi) is now a viable research tool for adult biting midges (Culicoides sonorensis). This breakthrough enables new studies into how these important arbovirus vectors transmit diseases.
Area of Science:
- Entomology
- Molecular Biology
- Vector-borne Diseases
Background:
- Biting midges (Culicoides spp.) are significant vectors of economically impactful arboviruses globally.
- Research on Culicoides vectors is limited by a lack of genomic data and molecular tools like RNA interference (RNAi).
Purpose of the Study:
- To establish RNA interference (RNAi) as a functional research tool in adult Culicoides sonorensis.
- To investigate the feasibility of using dsRNA injection for gene knockdown in adult midges.
Main Methods:
- Transcriptome analysis to identify RNAi pathway components.
- Injection of double-stranded RNA (dsRNA) targeting green fluorescent protein (dsGFP) as a control.
- Injection of dsRNA targeting the Culicoides sonorensis inhibitor of apoptosis protein 1 (CsIAP1) gene.
- Monitoring of transcript levels and median survival rates post-injection.
Main Results:
- Successful establishment of RNAi in adult C. sonorensis.
- Injection of dsRNA targeting CsIAP1 led to a 40% reduction in transcript levels.
- CsIAP1 knockdown resulted in a 73% decrease in median survival compared to controls.
- Control dsGFP injection did not significantly impact survival, supporting virus transmission models.
Conclusions:
- RNAi is a feasible and powerful tool for functional genomics in adult C. sonorensis.
- The conserved function of inhibitor of apoptosis protein 1 (IAP1) was confirmed in this species.
- This advancement will significantly accelerate research into the vector competence of C. sonorensis.
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