Expression Analysis of Hormone Receptor 38 (HR38) and Ecdysone-Induced Protein 75 (E75) Genes and Their Functional Implications in the Development of Heortia vitessoides Moore.

HR38 and E75 are early 20-hydroxyecdysone (20E)-responsive nuclear receptors that play important roles in insect molting and metamorphosis. Here, we cloned and characterized HvHR38 and HvE75 from Heortia vitessoides and analyzed their conserved domains and phylogenetic positions. Both genes exhibited distinct stage- and tissue-specific expression patterns closely associated with ecdysteroid-regulated developmental processes. Hormone-induction assays further demonstrated that the transcription of HvHR38 and HvE75 was strongly activated by 20E. RNA interference targeting either gene resulted in significant transcript knockdown, accompanied by incomplete molting, pupal deformities, and molting failure, ultimately leading to markedly reduced survival, with dsHvE75 causing the highest lethality. Collectively, these results suggest that HR38 and E75 function as key components of the early 20E-responsive transcriptional network involved in molting regulation, and highlight their potential as RNAi targets for species-specific and environmentally sustainable pest management.