RNA interference targeting trehalase genes induced larval mortality and developmental malformations in Henosepilachna vigintioctopunctata

BACKGROUND: Trehalases (Tres), key enzymes in energy metabolism and chitin biosynthesis, are crucial for insect growth and development. Although the essential roles of trehalase have been demonstrated in several insects, the functional diversification of trehalase family members and their potential as RNA interference (RNAi) targets in Henosepilachna vigintioctopunctata remain unclear. RESULTS: Seven HvTre genes were identified. Developmental expression patterns showed pronounced stage-dependent variation in soluble HvTre1 genes, whereas membrane-bound HvTre2 genes remained relatively stable. RNAi bioassays revealed that silencing HvTre1-1 or HvTre1-5 reduced the survival rates of first-instar larvae to approximately 30% and 36%, respectively, significantly lower than those observed after silencing the other HvTre genes. Biochemical analyses in first-instar larvae indicated marked disruption of carbohydrate metabolism: dsHvTre1-1 and dsHvTre1-5 significantly reduced trehalose and glycogen levels, and HvTre1-1 knockdown further decreased glucose content and trehalase activity. In fourth-instar larvae, silencing HvTre1-1 or HvTre1-5 significantly reduced pupation and adult emergence rates and caused severe developmental deformities. Conversely, in adults developed from double-stranded RNA-treated fourth-instar larvae, biochemical assays showed increased glycogen and glucose levels as well as trehalase activity, accompanied by reduced chitinase activity and significantly decreased expression levels of HvCHS and HvUAP, which are members of the chitin biosynthesis pathway. CONCLUSIONS: These results provide insight into the stage-dependent roles of trehalase in maintaining carbohydrate homeostasis and chitin-associated development in this pest and highlight HvTre1-1 and HvTre1-5 as promising RNAi targets for managing H. vigintioctopunctata. © 2026 Society of Chemical Industry.