Foliar spray double-stranded RNA targeting HvIAP1 induces high larval and adult mortality in Henosepilachna vigintioctopunctata.

Background: Exogenous double-stranded RNA (dsRNA) has the potential to serve as an effective alternative to conventional chemical pesticides for the control of insect pests, because it can specifically inhibit essential gene expression in these organisms. However, identifying suitable gene targets remains a crucial step in the development of RNA interference (RNAi)-based pest control strategies.

Results: In this study, three apoptosis-related genes were selected to evaluate their potential for RNAi-induced lethality in Henosepilachna vigintioctopunctata via foliar spray dsRNAs. Our results revealed that silencing of HvIAP1 (inhibitor of apoptosis protein 1) had a significant lethal effect on larvae, whereas silencing of HvAIF1 and HvASPP1 did not, correlating with distinct expression patterns. Larvae ingested leaves sprayed with bacterially expressed dsHvIAP1 at a concentration of 100 ng/cm resulting in the impairment of cuticle tanning, cessation of feeding, and ultimately, 100% mortality within 7 days. In addition, the potential of dsHvIAP1 to mediate for adult control was also investigated and showed that administration of 200 ng/cm dsHvIAP1 resulted in 100% adult mortality within 9 days, accompanied by a significant reduction in leaf consumption and suppression of HvIAP1 expression compared with the dsGFP group.

Conclusions: Our findings demonstrate that HvIAP1 is a highly lethal molecular target with a notable difference in the concentration required for larval and adult mortality. These findings provide a foundation for the future development of RNAi pesticides for environmentally friendly control of H. vigintioctopunctata. © 2025 Society of Chemical Industry.