Partner of bursicon Regulates Pheromone Gland Development and Sex Pheromone Biosynthesis in Helicoverpa armigera.

Bursicon, a heterodimeric neuropeptide composed of Burs-α and its binding subunit Partner of bursicon (Pburs), is primarily known to regulate insect cuticle tanning and also participates in wing expansion, reproduction and immunity. Pburs is highly expressed during pheromone gland (PG) maturation in female Helicoverpa armigera, a major agricultural pest, indicating its potential role in PG development and function. In this study, we cloned the full-length coding sequence of HaPburs and verified its high conservation across insects. qPCR revealed PG transcripts peaking at 48 h post-emergence in scotophase. RNAi-mediated knockdown reduced HaPburs transcript levels by 60.01%, resulting in abnormal PG morphology characterized by irregular melanized protrusions. Silencing HaPburs lowered the major sex pheromone component (Z)-11-hexadecenal by 42.66%, reduced male attraction and mating rates to 59.15% and 56.25% of controls, and markedly decreased cumulative fecundity. HaPburs-knockdown significantly downregulated the transcription of HaPKA and HaACC, two key genes involved in sex pheromone biosynthesis. These results suggest that HaPburs mediates PG morphogenesis and sex pheromone biosynthesis, further modulating sex pheromone-mediated reproductive communication in H. armigera. The study expands the known reproductive functions of bursicon and provides a promising molecular target for eco-friendly pest management.