RNAi-Based Functional Genomics in Hemiptera

SIMPLE SUMMARY: RNA interference (RNAi) is a powerful strategy to understand the function of novel and critical insect genes. In this review, we highlight the pros and cons of using RNAi as a functional genomics tool, the range of applications and explore RNAi delivery approaches such as topical and carrier/nano-particle-mediated RNAi for silencing insect genes in Hemiptera. We explore factors contributing to observed variations in RNAi efficiency and possible solutions to improve RNAi based investigations. We briefly summarise and provide experimental insight on the key RNAi studies in agricultural hemipteran pests that will be applicable to lesser-studied hemipteran’s, as well as informing functional genomics studies across diverse insect pests. ABSTRACT: RNA interference (RNAi) is a powerful approach for sequence-specific gene silencing, displaying tremendous potential for functional genomics studies in hemipteran insects. Exploiting RNAi allows the biological roles of critical genes to be defined and aids the development of RNAi-based biopesticides. In this review, we provide context to the rapidly expanding field of RNAi-based functional genomics studies in hemipteran insects. We highlight the most widely used RNAi delivery strategies, including microinjection, oral ingestion and topical application. Additionally, we discuss the key variables affecting RNAi efficacy in hemipteran insects, including insect life-stage, gene selection, the presence of nucleases, and the role of core RNAi machinery. In conclusion, we summarise the application of RNAi in functional genomics studies in Hemiptera, focusing on genes involved in reproduction, behaviour, metabolism, immunity and chemical resistance across 33 species belonging to 14 families.