Foxo Directly Regulates The Expression Oftor/S6kandvitellogeninto Modulate The Fecundity Of The Brown Planthopper

As a conserved transcription factor, FoxO plays a crucial role in multiple physiological processesin vivo, including stress resistance, longevity, growth and reproduction. Previous studies on FoxO have focused on human, mouse,Drosophila melanogasterandCaenorhabditis elegans, while there are few reports on agricultural pests and little is known about how FoxO modulates insect fecundity. In Asia, the brown planthopper (BPH)Nilaparvata lugens(Stal) is one of the most serious pests in rice production and high fecundity is the basis of the outbreak of BPH. Here, using the genome-wide ChIP-seq ofNlFoxO in BPH, we found thatNlFoxO binds to the promoters ofribosomal proteinS6 kinase(NlS6K)andserine/threonine-protein kinase mTOR(NlTOR)and increases their expression levels. We also found that NlFoxO directly binds to the exon ofvitellogenin(NlVg)and has a specific inhibitory effect on its expression. In addition, the number of eggs laid and their hatching rate decreased significantly after injection ofNlFoxOdouble-stranded RNA into BPH adults. Our findings provide direct evidence that FoxO modulates insect fecundity through binding to the promoters ofNlS6K, NlTORand the exon ofNlVgand affecting their gene expression in the Vg network.