The post-transcriptional gene silencing technique RNA interference (RNAi) is showing great

potential for the development of a new strategy for a safe and specific control of important pest insects; however, the efficacy of RNAi in insects is highly variable.

In this proposal, the applicant will develop novel delivery systems that could enhance the RNAi efficiency in insects by attempting to improve the persistency of the dsRNA in the insect body and the cellular uptake from the gut. First, different delivery systems will be developed, including dsRNA-producing bacteria, virus-induced RNAi, dsRNA coated by biodegradable polymers and dsRNA protected by liposomic agents. In a second phase, RNAi efficiency will be evaluated in a number of carefully selected pest species covering a broad taxonomical range and exhibiting distinct RNAi responses. In a final part, starting with the best working delivery system(s) from the first phase of the research, an attempt will be made to further enhance the efficiency of RNAi in the selected species by optimizing the dsRNA design itself, including target gene, gene region and sRNA length.

This project should lead to a more clear understanding of how RNAi efficiency can be improved by enhancing dsRNA stability in the insect body, improving uptake from the gut and optimizing the dsRNA design. It will also directly lead to the development of a new, environmentally safe strategy to control important pest insects without the need for GMO plants.