Decoding the potential mechanisms of 20-hydroxyecdysone (20E) terminating diapause of Pieris rapae through integrated...

Pieris rapae is a serious pest on cruciferous vegetables, and diapause is a key event for its overwintering survival. Our previous study demonstrated that 20-hydroxyecdysone (20E) is a crucial factor in diapause regulation. However, the mechanism by which 20E regulates diapause remains unknown.

Here, we showed that diapause pupae of P. rapae exhibited lower 20E biosynthesis gene expression than non-diapause pupae, and 20E treatment effectively terminated diapause. Furthermore, we conducted a comprehensive analysis that integrated transcriptome data from diapause pupae after 20E injection with that from both diapause and non-diapause, and identified a total of 337 up-regulated and 937 down-regulated target genes of 20E terminating diapause. Further investigations found that 20E treatment inhibited FoxO expression and promoted S6K expression in diapause pupae, and injection of the S6K inhibitor rapamycin and double-stranded RNA (dsRNA) into non-diapause pupae resulted in the developmental delay. Additionally, the results showed 20E treatment altered the expression of genes related to lipid metabolism, including the synthetic genes ELOVL, SCD, and FAR, as well as the degradation gene ACOX1. This was accompanied by a reduction in triglyceride content and enhanced lipid dissociation. Moreover, antioxidant enzyme genes GST, SOD and CAT were found to express highly in diapause pupae, and their gene expression and enzyme activity were inhibited by 20E injection.

This study systematically analyzes genes responding to 20E in diapause pupae of P. rapae, decodes the potential molecular mechanisms of 20E terminating diapause, and provides support for the utilization of ecdysone analogs as pesticides in diapause-based pest management. © 2025 Society of Chemical Industry.