Boosting dsRNA delivery in plant and insect cells with peptide- and polymer-based carriers: case-based current status and future perspectives.

Abstract Since the discovery of this naturally occurring endogenous regulatory and defence mechanism, RNA interference (RNAi) has been exploited as a powerful tool for functional genomic research. In addition, it has evolved as a promising candidate for a sustainable, specific and ecofriendly strategy for pest management and plant improvement. A key element in this technology is the efficient delivery of dsRNAs into the pest or plant tissues. While several examples using transgenic plants expressing the dsRNAs have proved the potential of this technology, nontransgenic approaches are investigated as alternatives, allowing flexibility and circumventing technical limitations of the transgenic approach. However, the efficacy of environmental RNAi is affected by several barriers, such as extracellular degradation of the dsRNA, inefficient internalization of the dsRNA in the cell and low endosomal escape into the cytoplasm, resulting in variable or low RNAi responses. In the medical field, carrier systems are commonly used to enhance RNA delivery and these systems are being rapidly adopted by the agricultural industry. Using four case studies, this chapter demonstrates the potential of carriers to improve the RNAi response in pest control for aquatic-living mosquito larvae and RNAi-resilient Lepidoptera and to cross the plant cell wall, allowing efficient environmental RNAi in plants.