Using dsRNA specific to integrin β1 subunit by suppressing immune and developmental processes to control a hot pepper pest, Helicoverpa assulta. Helicoverpa assulta transcriptome

Integrin is a cell surface heterodimeric protein interacting with the extracellular matrix and mediating environmental signals through cell membranes. A full-length cDNA sequence of the integrin β1 subunit gene (HaITGb1) was cloned from the Oriental tobacco budworm, Helicoverpa assulta, and analyzed for its physiological function in both immune response and development. HaITGb1 was expressed in all developmental stages from egg to adult and in all tested larval tissues of hemocytes, fat body, gut, and epidermis. Utilizing an RNA interference (RNAi) approach, injection of -a specific double-stranded RNA (dsRNA) in larvae suppressed HaITGb1 transcript levels and significantly impaired hemocytes in their extracellular matrix adherence properties. Furthermore, the RNAi treatment significantly suppressed hemocyte nodule formation in response to bacterial challenge, which resulted in significantly enhanced susceptibility to both pathogenic and non-pathogenic bacteria. The RNAi treatment also interfered with H. assulta larval and pupal development. These results suggest that dsRNA specific to HaITGb1 could be used to develop a novel control technique against H. assulta by dsRNA alone or by combining it with other biological control agents.