Identification and functional characterization of a beta-glucosidase gene involved in solanine degradation in the ladybird beetle Henosepilachna vigintioctopunctata

Background: Solanaceous Plants synthesize the alkaloid alpha-solanine as a chemical defense against herbivorous insects. The plant feeder ladybird Henosepilachna vigintioctopunctata (Coleoptera: Coccinellidae), specialized on solanaceous hosts, causes significant economic losses to solanaceous crops such as potato, tomato and eggplant through its voracious feeding activity. However, little is known about the underlying adaptive mechanisms that enable Henosepilachna vigintioctopunctata to neutralize this plant toxin.

Results: Here, through transcriptome analysis and quantitative polymerase chain reaction (qPCR) validation, we identified a beta-glucosidase gene, HvBgla1, that is significantly up-regulated in response to alpha-solanine ingestion, with particularly high expression observed in midgut tissues. RNA interference (RNAi) mediated silencing of HvBgla1 reduced alpha-solanine degradation, leading to toxin accumulation in the midgut and hindgut. This was accompanied by a decrease in the degradation product solanidine in the midgut, and a reduction in the body weight of newly emerged adults from RNAi-treated larvae. Additionally, phylogenetic analysis revealed that HvBgla1 originated from a lineage-specific duplication clade exclusive to the tribe Epilachnini.

Conclusion: These findings suggest that HvBgla1 plays a crucial role in alpha-solanine detoxification, allowing Henosepilachna vigintioctopunctata to overcome solanaceous plant defenses. © 2026 Society of Chemical Industry.

Henosepilachna vigintioctopunctata; beta‐glucosidase; detoxification; solanine; toxins.