POU transcription factor nubbin ( HvNub ) is required for the wing development and reproduction in the 28‐spotted ladybeetle, Henosepilachna vigintioctopunctata

BACKGROUND: The conserved POU-homeodomain transcription factor Nubbin (Nub) is essential for insect development. Given the agricultural impact of the 28-spotted ladybeetle, Henosepilachna vigintioctopunctata, a major solanaceous crop pest, we characterized its nub ortholog (HvNub) and evaluated its potential for RNA interference (RNAi)-based control. RESULTS: HvNub encodes a 485-amino acid protein with conserved homeodomain and POU-specific domains, phylogenetically clustering with coleopteran insects. Expression analysis revealed ubiquitous HvNub transcripts, peaking in eggs, and enriched in heads, ovaries and thoracic segments (T2/T3). RNAi silencing in larvae caused severe developmental defects: 55% mortality and 45% deformity by pupation, with 0% adult survival. Phenotypes included wing malformations, fluid accumulation and impaired melanization, linked to dysregulation of 20-hydroxyecdysone pathway genes (Hvshd, HvECR, HvUSP, HvE75, HvFtzF1) and Hvebony. Crucially, adult females subjected to RNAi exhibited atrophied ovaries, 60% reduced fecundity and near-complete loss of egg hatchability (0.9% versus 83% controls), and with unhatched eggs containing deformed larvae. This was associated with downregulation of HvVg and HvVgR, and embryonic transcriptome dysregulation affecting cell structure, binding, endocrine system and signal transduction. CONCLUSION: Our findings demonstrate HvNub's critical roles in postembryonic development and female reproduction, establishing its high potential as an RNAi target for managing H. vigintioctopunctata. © 2026 Society of Chemical Industry.