Rna N-6-Methyladenosine Modification Suppresses Replication Of Rice Black Streaked Dwarf Virus And Is Associated With Virus Persistence In Its Insect Vector

N-6 methylation of adenosine (m(6)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 m(6)A effects on the same or different viruses have revealed contradictory roles for m(6)A in the viral life cycle. In this study, we sought to define the role of m(6)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 m(6)A in midgut cells of SBPHs. We then cloned two genes (LsMETTL3 and LsMETTL14) that encode m(6)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 m(6)A levels were negatively correlated with virus replication. More importantly, our results revealed that m(6)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.