Abstract
N6 methylation of adenosine (m6 A) was recently discovered to play a role in regulating the life cycle of various viruses by modifying viral and host RNAs. However, different studies on m6 A effects on the same or different viruses have revealed contradictory roles for m6 A in the viral life cycle. In this study, we sought to define the role of m6 A on infection by rice black streaked dwarf virus (RBSDV), a double-stranded RNA virus, of its vector small brown planthopper (SBPH). Infection by RBSDV decreased the level of m6 A in midgut cells of SBPHs. We then cloned two genes (LsMETTL3 and LsMETTL14) that encode m6 A RNA methyltransferase in SBPHs. After interference with expression of the two genes, the titre of RBSDV in the midgut cells of SBPHs increased significantly, suggesting that m6 A levels were negatively correlated with virus replication. More importantly, our results revealed that m6 A modification might be the epigenetic mechanism that regulates RBSDV replication in its insect vector and maintains a certain virus threshold required for persistent transmission.