Persistent Spodoptera frugiperda rhabdovirus infection in Sf9 cells is not restricted by Wolbachia wMelPop-CLA and wAlbB strains and is targeted by the RNAi machinery.

The endosymbiotic bacterium Wolbachia pipientis confers RNA virus refractoriness in Drosophila and Aedes mosquitoes. Questions remain about the Wolbachia- virus restriction phenotype and how extensive this phenomenon may be within other arthropods. Here, we generated two Spodoptera frugiperda cell lines stably transinfected with two strains of Wolbachia , w AlbB and w MelPop-CLA. Despite the high density of Wolbachia in stably infected Sf9 cells, RT-PCR indicated the presence of the negative-sense RNA virus Spodoptera frugiperda rhabdovirus (SfRV) in Wolbachia -infected and uninfected cell lines. No differences in the replication of SfRV between Sf9 and Wolbachia -infected cells was found. RNA-Seq analysis of the parental Sf9 cells supported SfRV's presence in these cells with abundant 20 nt virus-derived small RNAs indicating active replication of SfRV in these cells. Overall, this study supports a growing body of evidence that Wolbachia does not restrict negative-sense RNA viruses and generates an in vitro model to examine Lepidoptera- Wolbachia virus interactions. • Generation of Spodoptera frugiperda (Sf9) cells stably infected with Wolbachia w MelPop and w AlbB strains. • RT-PCR revealed Spodoptera frugiperda rhabdovirus (SfRV) persistently infects Wolbachia -infected and uninfected cell lines. • RT-qPCR of SfRV genomic RNA suggests SfRV was not affected by Wolbachia infection. • Analysis of small RNA sequencing indicated that the RNAi response in Sf9 cells targets SfRV. • Endogenous SfRV-like loci in the Sf9 genome produce abundant 27-29 nt piRNAs. [ABSTRACT FROM AUTHOR]