Plant viral RNA silencing suppressor(RSS)proteins have been
shown to interfere with different steps of the RNA silencing pathway
as reviewed in and The majority of RSS act by sequestering short-interfering RNA(siRNA)
such as tombusvirus P19 and invertebrate Flock House virus(FHV)B2 proteins or by inhibiting
the activity of Argonaute(AGO)protein(s)as reported for cucumber mosaic virus(CMV)2b protein
P19 and B2 proteins exhibit RSS activity in both
plant and insect cells,while CMV 2b acts as a RSS only in plants