RNA interference-mediated silencing of vATPase subunits A and E affect survival and development of the 28-spotted ladybeetle, Henosepilachna vigintioctopunctata

Abstract

RNA interference (RNAi) has emerged as a powerful tool for developing novel management strategies for controlling insect pests. The 28-spotted ladybeetle, Henosepilachna vigintioctopunctata is one of the most important pests attacking solanaceous plants in Asia. In this study, the potential of dietary RNAi to manage H. vigintioctopunctata was investigated using both in vitro synthesized and bacterially expressed double-stranded RNAs (dsRNAs) of HvvATPase A and HvvATPase E. The expression levels of HvvATPase A and HvvATPase E were higher in Malpighian tubules than in other tissue types. The silencing of HvvATPase A and HvvATPase E led to significant mortality in H. vigintioctopunctata larvae. In addition, the ingestion of HvvATPase A and HvvATPase E significantly deterred feeding behavior and subsequently arrested the development of H. vigintioctopunctata. Notably, the bacterially expressed dsRNAs consistently caused higher mortality in larvae and adults. Finally, the nontarget effects of the dsRNAs of H. vigintioctopunctata on the predatory ladybeetle Propylaea japonica were evaluated. P. japonica 1st instar larvae were administered vATPase A and vATPase E dsRNAs from H. vigintioctopunctata and P. japonica under the worst-case scenario, in which dsGFP served as negative control. There were significant effects of dsHvvATPase A on P. japonica at the transcriptional level but not at the organismal level, whereas dsHvvATPase E did not effect P. japonica at either the transcriptional or the organismal level. Collectively, the results of the study suggest that HvvATPase A and HvvATPase E can act as novel molecular targets for the control of H. vigintioctopunctata.