Oral RNAi of diap1 in a pest results in rapid reduction of crop damage

Selecting an appropriate target gene is critical to the success of feeding RNA interference (f-RNAi)-based pest control. Gene targets have been chosen based on their ability to induce lethality. However, lethality induction by f-RNAi is slow-acting and crop damage can progress during this time. Here, we show that f-RNAi of death-associated inhibitor of apoptosis protein 1 (diap1), but not two conventional targets vacuolar ATPase subunit A and E, induces acute feeding cessation in the solanaceous pest, Henosepilachna vigintioctopunctata during 24-48 hours. We also found that the feeding cessation by diap1 f-RNAi has species-specificity and occurs with only 1.6 ng dsRNA. Our results suggest that diap1 is an appropriate target in the context of rapid reduction of crop damage. We propose that acute feeding disorder should be assessed as a novel criterion for selecting appropriate target genes for RNAi-based pest control in addition to the conventional criterion based on lethality.