Response of CDA 5 in Hyphantria cunea to Bt toxin ingestion and Knockdown in transfected Sf9 cells

Chitin deacetylases ( CDA s) are critical enzymes required for chitin degradation, which play an important role in modifying the physical properties of insect cuticles and peritrophic matrices. A novel chitin deacetylase gene ( hccda5 ) was identified from Hyphantria cunea . The recombinant expressed Hc CDA 5 protein, containing a chitin deacetylase domain ( CDAD ), did not show chitin deacetylase activity, but instead showed a strong chitin‐binding activity. Transcriptional analysis using qRT ‐ PCR indicated that hccda5 was mainly expressed in the midgut of H. cunea larvae. Feeding H. cunea larvae with Bt ( Bacillus thuringiensis ) Cry1A protein induced its downregulation. The gene of hccda5 was successfully silenced by different ds RNA s in insect cell line ( Spodoptera frugiperda line, Sf9), which provided a tool to study the function of an expressed gene in insect cell line and laid a foundation for RNA i of hccda5 in H. cunea larvae.