Jinggangmycin-induced NlPR and NlABD4 genes regulate fecundity in the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae)

The brown planthopper (BPH), Nilaparvata lugens, is a typical insecticide-induced resurgence rice pest that caused severe damage to rice in the Asian areacountries. Previous studies have shown that the fungicide, Jinggangmycin (JGM), which is used to control rice sheet blight disease, could stimulate BPH fecundity, but the molecular mechanism remains to be further explored. In this study, based on transcriptomic analysis, we found that the PI3K-Akt signaling pathway was significantly enriched in BPH after feeding on JGM-treated rice, in which NlPR and NlABD4 genes were significantly up-regulated. We further investigated the physiological functions of NlPR and NlABD4 by RNAi, and the results showed that silencing of NlPR and NlABD4 markedly prolonged the developmental period of nymphs and significantly influenced nymph feeding behavior. Moreover, the NlPR and NlABD4 are specifically expressed in the ovary in female adults. Knockdown of NlPR and NlABD4 in the nymphal stage significantly reduced the antioxidant enzyme activity and gene expression levels in adults and inhibited female ovary development, reduced the expression levels of Vg and VgR, shortened the pre-oviposition and oviposition period, and reduced female reproduction. The current study revealed the physiological functions of NlPR and NlABD4 in the fecundity of BPH and demonstrated that the JGM stimulated BPH fecundity by altering the PI3K-Akt signaling-related genes. These results contribute to an understanding of insecticide-induced resurgence, offer novel insights for control of BPH, and provide a new strategy for the comprehensive management of BPH.