The microRNA pathway activation in insect cell model upon Autographa californica multiple nucleopolyhedrovirus infection

Background: The immune system of insects exerts fundamentally different antiviral mechanisms thanmammals. MicroRNAs (miRNAs) play vital roles in developing insect antiviral immunity. MiRNAs expressionprofiles of insects changed significantly during baculovirus infection. Methods: Differential expression profiles ofmiRNAs in Spodoptera frugiperda were monitored by next-generation sequencing (NGS) and RT-qPCR duringAutographa californica multiple nucleopolyhedrovirus (AcMNPV) infection. The transcription levels of genes weredetected by RT-qPCR. The 50% tissue culture infective dose (TCID50) endpoint dilution assay was used to determinethe proliferation of progeny virus. Results: NGS revealed that 49 miRNAs were differentially expressed in Sf9 cells,and 10 of them were significantly up- or down-regulated. Though RT-qPCR analysis, we observed the similar trendsfor the expression patterns of significantly differentially expressed miRNAs from NGS. Moreover, the transcriptionlevels of core genes, Exportin5, Dicer1, and Argonaute1, in miRNA biogenesis pathways were significantly increasedafter AcMNPV infection. For five selected miRNAs, miR-34-5p could regulate the proliferation of baculovirusprogeny virus and energy metabolism. Conclusion: The miRNAs biogenesis pathway in Sf9 cells plays an importantrole and may be stimulated to resist AcMNPV infection. This work provides evidence for the molecular mechanismof baculovirus-insect interaction and offers novel ideas and directions for green pest control technology.