Joshi_2025_Int.J.Biol.Macromol__148673

Helicoverpa armigera, a devastating agricultural pest, poses significant threats to global crop productivity. Targeting the Juvenile Hormone (JH) degradation pathway might offer a promising approach for pest management due to its pivotal role in insect development and reproduction. In this study, we developed a nano clay-based formulation of double-stranded RNA (dsRNA) targeting three key JH degradation pathway genes: Juvenile Hormone Esterase (HaJHE), Juvenile Hormone Epoxy Hydrolase (HaJHEH), and Juvenile Hormone Diol Kinase (HaJHDK). Expression analysis revealed tissue and stage-specific patterns of these genes, with qRT-PCR confirming high expression levels of specific isoforms in key developmental transition: the pre-pupal stage. Treatment with bacterially expressed dsRNAs achieved >50 % silencing of target genes, resulting in delay in larval-to-pupal transitions. Bioassay demonstrated that treatment with LDH-based dsRNA nanocarrier resulted in downregulation of target genes, causing developmental delays, including prolonged larval and pupal stages. Metabolomic analysis further indicated reduced accumulation of JH degradation pathway metabolites, highlighting the pathway-specific action of dsRNAs. Furthermore, combinatorial application of dsRNAs resulted in higher mortalities compared to individual dsRNA application. These results suggest that the application of the LDH-based dsRNA nanocarrier formulation against H. armigera JH degradation pathway for spray-induced gene silencing could serve as a potential insect management strategy.