Complete protection from Henosepilachna vigintioctopunctata by expressing long double‐stranded RNAs in potato plastids

Abstract RNA interference (RNAi) has emerged as a powerful technology for pest management. Previously, we have shown that plastid‐mediated RNAi (PM‐RNAi) can be utilized to control the Colorado potato beetle, an insect pest in the Chrysomelidae family; however, whether this technology is suitable for controlling pests in the Coccinellidae remained unknown. The coccinellid 28‐spotted potato ladybird ( Henosepilachna vigintioctopunctata ; HV) is a serious pest of solanaceous crops. In this study, we identified three efficient target genes ( β‐Actin , SRP54 , and SNAP ) for RNAi using in vitro double‐stranded RNAs (dsRNAs) fed to HV, and found that dsRNAs targeting β‐Actin messenger RNA (ds ACT ) induced more potent RNAi than those targeting the other two genes. We next generated transplastomic and nuclear transgenic potato ( Solanum tuberosum ) plants expressing HV ds ACT . Long ds ACT stably accumulated to up to 0.7% of the total cellular RNA in the transplastomic plants, at least three orders of magnitude higher than in the nuclear transgenic plants. Notably, the transplastomic plants also exhibited a significantly stronger resistance to HV, killing all larvae within 6 d. Our data demonstrate the potential of PM‐RNAi as an efficient pest control measure for HV, extending the application range of this technology to Coccinellidae pests.