In agroinfiltrated Nicotiana benthamiana leaves we
show for the first time for a cytorhabdovirus,lettuce necrotic yellows virus(LNYV),that one of the nucleocapsid core proteins,phosphoprotein(P)has relatively weak local RSS activity and delays systemic
silencing of a GFP reporter.Analysis of GFP small RNAs
indicated that the Pprotein did not prevent siRNA
accumulation. To explore RSS activity in insects,we used a Flock House virus replicon system in
Drosophila S2 cells.In contrast to the plant host,LNYV P protein did not exhibit RSS activity in the insect cells. Taken together our results suggest that P protein may target plant-specific components of RNA silencing post siRNA biogenesis.