RNA interference-mediated knockdown of IAP in Lygus lineolaris induces mortality in adult and pre-adult life stages

In recent years, RNA interference (RNAi) has been validated as a viable approach for functional genetic studies in non-model organisms. In this report we demonstrate the efficacy of RNAi in the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Miridae: Hemiptera). A L. lineolaris inhibitor of apoptosis gene (LlIAP) has been identified and cloned. The translated sequence encodes a 381 amino acid protein similar to other insect IAPs and contains two conserved baculovirus inhibitor of apoptosis protein repeat (BIR) domains. Microinjection of double stranded RNA (dsRNA) corresponding to two disparate portions of the gene resulted in decreased LlIAP mRNA quantities relative to controls. Both nymphs and adult specimens injected with IAP dsRNA exhibited significantly reduced lifespan compared with those injected with non-insect dsRNA (eGFP). Thus, RNAi-mediated knockdown of LlIAP expression has been correlated with a lethal phenotype in adults and nymphs.