Abstract: 【Aim】 This study focuses on the cloning and prokaryotic expression of the sex pheromone biosynthesis activating neuropeptide gene PxylPBAN in the diamondback moth, Plutella xylostella. Additionally, the effects of RNAi-mediated PxylPBAN silencing on the expression of genes involved in both the juvenile hormone pathway and the sex pheromone synthesis pathway were detected to explore the role of PxylPBAN in sex pheromone synthesis. 【Methods】 The full-length CDS of PxylPBAN  in P. xylostella was cloned using RT-PCR. PxylPBAN was expressed in a prokaryotic expression system and subsequently purified. RNAi was conducted by injecting dsPxylPBAN into female pupae of P. xylostella, followed by the RT-qPCR verification of the expression levels of PxylPBAN, juvenile hormone pathway genes PxylJHAMT, PxylnJHBP, PxylhJHBP and PxylMet, as well as the sex pheromone synthesis pathway genes PxylACC and PxylFAR6 at 24, 48 and 72 h post injection. 【Results】 The cloning process successfully generated a 582 bp full-length CDS for PxylPBAN (GenBank accession number: LOC105391112), of P. xylostella, encoding a 193 amino acid protein with the estimated molecular weight of approximately 21.85 kD. The recombinant PxylPBAN protein was produced through prokaryotic expression. RNAi result revealed a significant down-regulation in expression level of PxylPBAN following the injection of dsPxylPBAN compared to the control group injected with dsEGFP of P. xylostella, with the most pronounced decrease observed at 24 h post injection. Additionally, the expression levels of PxylJHAMT, PxylnJHBP, PxylhJHBP, PxylMet, PxylACC and PxylFAR6 of P. xylostella in the dsPxylPBAN-injected group were significantly reduced as compared to those in the control group. 【Conclusion】 This study successfully obtained the recombinant PxylPBAN protein and identified PxylPBAN as a key gene in the juvenile hormone pathway and sex pheromone synthesis pathway in P. xylostella. These findings establish a theoretical basis for understanding the regulatory relationship between PxylPBAN and juvenile hormones in sex pheromone biosynthesis in P. xylostella.

Key words:  Plutella xylostella, pheromone biosynthesis activating neuropeptide, juvenile hormone, gene cloning, prokaryotic expression, RNA interference