Functional characterization of chitin deacetylase 1 gene disrupting larval-pupal transition in the drugstore beetle using RNA interference

Chitin deacetylases (CDAs) are chitin degradation enzymes that strictly regulate growth and development in insects. In this study, we identified and characterized a full-length cDNA of the CDA gene (SpCDA1) in the drugstore beetle, Stegobium paniceum. The open reading frame of SpCDA1 (1614 bp) encoded a 537 amino acid protein, which possessed typical domain structures of CDAs. Phylogenetic comparison to other insect CDAs revealed that SpCDA1 belongs to Group Ib CDAs. Quantitative real-time PCR analyses showed that SpCDA1 was highly expressed in late larval stages. Significant increase of SpCDA1 transcript level in the larvae was observed upon the exposure of 20-hydroxyecdysone. Injection of double-stranded RNA (dsRNA) of SpCDA1 into the late larvae significantly reduced SpCDA1 transcript levels, resulted in larval-pupal molting difficulty and produced high larval mortality. After 15 days, the survival rate of S. paniceum in dsSpCDA1 group was significantly reduced by 72% compared to the control. The results demonstrated that SpCDA1 is essential for successful larval-pupal transition in S. paniceum and this gene may be a potential target for pest control.