Henosepilachna vigintioctopunctata is a notorious defoliator of many solanaceous and cucurbitaceous plants. Today, two environmentally friendly control methods for the beetles are: 1) conservation and augmentation of indigenous natural enemies (Ze et al., 2023a); 2) the use of RNA interference (RNAi) product (Guo et al., 2023, Liu et al., 2023, Ze et al., 2023a). In order to improve the compatibility of the two promising approaches, a dsRNA-based pesticide should exert an antifeeding effect to reduce leaf damage, and should act as a slow-acting insecticide that can keep the pests living for a substantial time period to provide food for predators and parasitoids (Ze et al., 2023a). Our most recent endeavor identifies a p-diphenol:dioxygen oxidoreductase laccase 2 gene Hvlac2. It is a suitable dsRNA target gene compatible with the two environmentally friendly control approaches (Ze et al., 2023a). This successful attempt promotes us to seek more potential target genes.

It is well known that normal legs, wings and mouthparts enable H. vigintioctopunctata beetles to forage host plants, settle on foliage and gnaw nutritious leaves. The walking, flying and feeding are driven by skeletal muscles that are attached at either end to the cuticle (Chapman, 1998). Therefore, disrupting cuticle structure by RNAi targeting specific genes may destroy the cuticular sites attached by skeletal muscles, and may impair muscle contraction and affect motion and locomotion. The resultant H. vigintioctopunctata beetles may be living and less moving, flying and feeding (Ze et al., 2023a). In this context, we noted aaquetzalli (aqz) gene in Drosophila melanogaster, which encodes a mammal homologue of proline-rich nuclear receptor coactivator (Pnrc) (Zhou et al., 2000). Dmaqz is required pleiotropically during Drosophila embryogenesis (Ivanov et al., 2004, Mendoza-Ortiz et al., 2018, Perrimon et al., 1996). Dmaqz mutant germline clones displays cuticular holes (Perrimon et al., 1996), loss of epithelial integrity and mislocalization of membrane proteins (Mendoza-Ortiz et al., 2018). However, whether deficiency of Pnrc in insects causes delayed death and exerts an antifeeding role remains to be proven.

In the current paper, we identified Hvpnrc and ascertained that RNAi against Hvpnrc impaired the larval-pupal-adult transition. The resultant beetles consumed less foliage and hardly oviposited, most of them remained alive for more than a week before death. Our results will enable to develop a novel control strategy via combining a dspnrc-based pesticide with biocontrol in H. vigintioctopunctata.