Genetic And Functional Analysis Of Potential Target For RNAi-based Control-NloxN1 Gene Of Nilaparvata Lugens

The brown planthopper(BPH),Nilaparvata lugens Stal(Hemiptera:Delphacidae),is a typical monophagous pest which only feeds on the rice.BPH is one of the most destructive insect pests in China and many southeastern Asian countries,causing a serious loss of rice yield every year.It has been reported that Fox transcription factors play critical roles in regulation of metabolism,proliferation,apoptosis,development,organogenesis,differentiation and control of oxidative stress through both activation and repression of target gene expression by multiple mechanisms.Therefore,it is significant to clarify the functions and molecular mechanism of Fox family,so that provides important theoretical basis for insect pest control.In this study,we cloned the NlFoxN1 cDNA sequence of FoxN subfamily from BPH.The ORF was 191 lbp in length and was potential to encode a 69.9kDa protein containing 636 amino acid residues.It has the typical conserved domain Forkhead(FH)of Fox family,a DNA-binding domain of Fox protein.The alignment analysis showed that a high amino acid identity on FH domain among different species of insects.qRT-PCR analysis showed that NlFoxNl has the highest expression in egg-hatching stage of BPH,and it is mainly expressed in the ovary.Then we employed RNA interference(RNAi)of NIFoxN1,and found that the RNAi significantly reduced the hatching rate of BPH,however,it didn’t influence the development of ovary and the number of eggs.In addition,it was found that knockdown of NIFoxN1 lead to a remarkable death rate during eclosion.All the results implied that NIFoxNl could regulate the development of embryo and the process of eclosion.Our results demonstrated that NlFoxN1 of BPH has important significance for RNAi-base pest control and enhanced our understanding of the molecular mechanism of Fox transcription.