Integrated transcriptomic and proteomic analyses revealed the participation of endogenous protease inhibitors in the regulation of protease gene expression in Helicoverpa armigera

Insects adapt to plant protease inhibitors (PIs) present in their diet by differentially regulating multiple digestive proteases. However, mechanisms regulating protease gene expression in insects are largely enigmatic. Ingestion of Capsicum annuum protease inhibitor-7 (CanPI-7) arrests growth and development of Helicoverpa armigera (Lepidoptera: noctuidae). Using de novo RNA sequencing and proteomic analysis, we examined the response of H. armigera larvae fed on recombinant C. annuum PI (CanPI) at different time intervals. Here, we present evidence supporting a dynamic transition in H. armigera protease expression upon CanPI feeding with general down-regulation of protease genes at early time points (0.5 to 6 h) and significant up-regulation of specific trypsin, chymotrypsin and aminopeptidase genes at later time points (12 to 48 h).