LAUSR

BACKGROUND Spodoptera frugiperda (S. frugiperda) is one of the significant migratory pests in the Global Alert issued by the Food and Agriculture Organization of the United Nations. As an insect-specific microbial insecticide, baculovirus has been used to control various pests. microRNA-34-5p (miR-34-5p) is related to regulating the growth, reproduction, and innate immunity to pathogens of insects, playing an essential role in host-virus interactions. In this study, we explored the critical function of miR-34-5p encoded by S. frugiperda in the anti-Autographa californica multiple Nucleopolyhedrovirus (AcMNPV), providing a reference for designing the miR-34-5p target biopesticide against S. frugiperda and a theoretical basis for widely applying microRNAs (miRNAs) in green pest control technology. RESULTS The miR-34-5p identified as down-regulated in Sf9 cells and S. frugiperda larvae infected by AcMNPV was focused on. The regulatory function of miR-34-5p in the AcMNPV-S. frugiperda interactions was studied by transfecting synthetic mimics and inhibitors and constructing recombinant bacmids with miR-34-5p overexpression. miR-34-5p inhibited the production of infectious budded virions (BVs) at the cellular and insect levels, inhibited the replication of the viral DNA and glucose metabolism, and increased the transcription level of the antimicrobial peptide gloverin. Furthermore, the virus genes odv-e66, ac78, and ie2 were demonstrated to be direct targets. CONCLUSION We systematically revealed the mechanism by which miR-34-5p is involved in the insect antiviral process. miR-34-5p inhibited the replication and infection of AcMNPV by directly targeting AcMNPV genes, especially ac78 and ie2. Our study provides a new direction and thinking for the prevention and green control of lepidopteran pests. This article is protected by copyright. All rights reserved.