Density dependent enhancement effect ofWolbachiaand the host RNAi response to a densovirus inAedescells

The endosymbiotic bacterium Wolbachia pipientis has been shown to restrict a range of RNA viruses in Drosophila melanogaster and transinfected dengue mosquito, Aedes aegypti . Here, we show that Wolbachia infection enhances replication of Aedes albopictus densovirus (AalDNV-1), a single stranded DNA virus, in Aedes cell lines in a density-dependent manner. Analysis of previously produced small RNAs of Aag2 cells showed that Wolbachia- infected cells produced greater proportions of viral derived short interfering RNAs as compared to uninfected cells. Additionally, we found production of viral derived PIWI-like RNAs (vpiRNA) produced in response to AalDNV-1 infection. Nuclear fractions of Aag2 cells produced a primary vpiRNA signature U 1 bias whereas the typical “ping-pong” signature (U 1 - A 10 ) was evident in the cytoplasmic fraction. This is the first report of the density-dependent enhancement of DNA viruses by Wolbachia . Further, we report the generation of vpiRNAs in a DNA virus-host interaction for the first time.