Proline-rich nuclear receptor coactivator (Pnrc), the Drosophila aaquetzalli homologue, is important in survival of Henosepilachna vigintioctopunctata

Abstract

To develop a novel control strategy via a combination of double stranded RNA (dsRNA)-based pesticide and biocontrol in Henosepilachna vigintioctopunctata, we endeavored to identify potential dsRNAs that can cause living and non-feeding beetles to provide food for predators and parasitoids. In this context, depletion of proline-rich nuclear receptor coactivator (Pnrc), the Drosophila melanogaster aaquetzalli homologue, damages cuticle integrity. In the current paper, RNA interference (RNAi) targeting Hvpnrc by an injection of 200, 500 or 1000 ng of dspnrc into the third instar larvae significantly reduced the level of corresponding transcript and repressed pupation and adult eclosion, in a dose-dependent manner. The resultant female adults were malformed, with misshapen elytra and hindwings. They seldom moved, consumed less potato foliage, and hardly laid eggs. Most Hvpnrc RNAi beetles remained alive for more than a week before death. Silencing of Hvpnrc at the fourth larval instar or pupal stages caused more severe defective phenotypes. The Hvpnrc depleted adults seldom moved and did not consume potato foliage. They did not oviposit and eventually died within 10 days post eclosion. Taken together, dspnrc can cause delayed death and can exert an antifeeding effect; a dspnrc-based pesticide may be compatible with biocontrol when applied to the potato field to control H. vigintioctopunctata.