A strategy for screening an inhibitor of viral silencing suppressors, which attenuates symptom development of plant viruses.

To find out whether we can control plant virus diseases by blocking viral RNA silencing suppressors (RSSs), we developed a strategy to screen inhibitors that block the association of RSSs with siRNAs using a surface plasmon resonance assay. The screened chemicals were tested in competition with RSSs for binding to siRNAs using a mobility shift assay. We then confirmed that tested chemicals actually inhibited the RSS activity in vivo using a protoplast assay which was developed for this purpose. This entire system can be adapted to screening inhibitors of not only plant viruses but also some animal viruses possessing RSSs.