There is only one report on the in vivo function of NSs from Tomato spotted wilt virus, the type member of Tospovirus genus, as a suppressor of PTGS [3] . There has been no further work on this protein. RNA silencing or PTGS is a major strategy by which plants mount defense responses against molecular parasites such as viruses [37, 38] . The RNA silencing pathway involves the initial processing of viral dsRNA into small interfering RNA (siRNA) duplexes of length 21-25 nt by DICER or its homologs. One of the strands of the siRNA incorporated into the RNA induced silencing complex (RISC) specifically targets viral mRNA with a complementary sequence for degradation [39] . Viruses evade such a defense response by expressing viral suppressors of RNA silencing (VSRs). VSRs encoded by viruses of different families and genera [40, 41] share no homology at the level of primary sequence and the mechanisms by which they inactivate the PTGS are different. The results presented in this manuscript implicate that NSs might act as a suppressor of PTGS by removing 59 phosphate from dsRNA, the substrate for DICER. It has been observed that DICER does not recognize the dephosphorylated dsRNA [42] and therefore removal of the 59 phosphate by NSs could eventually block the PTGS pathway. Interestingly, even in some animal viruses dephosphorylated viral RNA fails to induce the Interferon pathway [43, 44] thereby suppressing the host defense mechanism. Further, ATP is required for the PTGS pathway. The ATPase activity of NSs might result in the suppression of this pathway. The ATPase and 59 phosphatase function of NSs could also be of functional importance in the replication and transcription of the virus. 