Overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors

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Overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors

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N. A. Ratcliffe, J. P. Furtado Pacheco, P. Dyson, H. C. Castro, M. S. Gonzalez, P. Azambuja and C. B. Mello,  Parasites and Vectors,  15:112. 2022.

This article presents an overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors. It first briefly summarises some of the disease-causing pathogens vectored by insects and emphasises the need for innovative control methods to counter the threat of resistance by both the vector insect to pesticides and the pathogens to therapeutic drugs. Subsequently, the state of art of paratransgenesis is described, which is a particularly ingenious method currently under development in many important vector insects that could provide an additional powerful tool for use in integrated pest control programmes. The requirements and recent advances of the paratransgenesis technique are detailed and an overview is given of the microorganisms selected for genetic modification, the effector molecules to be expressed and the environmental spread of the transgenic bacteria into wild insect populations. The results of experimental models of paratransgenesis developed with triatomines, mosquitoes, sandflies and tsetse flies are analysed. Finally, the regulatory and safety rules to be satisfied for the successful environmental release of the genetically engineered organisms produced in paratransgenesis are considered.

Summary of the analysis and selection of bacteria from vector microbiota for cultivation and genetic modification in vitro. The microorganism (A) is genetically modified by the insertion of an exogenous gene in a plasmid (B) or directly into the bacterial chromosome (C). The transgenic bacteria are offered to adult insects through an attractant bait. In the insect’s digestive tract, the genetically modified microorganism expresses a peptide capable of interrupting the transmission of the parasite or a dsRNA that can silence genes in the parasite or the vector, if these are sensitive to RNA interference, thereby blocking parasite development. Abbreviations: dsRNA, Double-stranded RNA Image from: Ratcliffe et al (2022) doi: 10.1186/s13071-021-05132-3