Hairpin RNAs have been used to confer resistance to viruses in plants through RNA silencing. However, it has not been demonstrated that RNA silencing was effective against inoculation by aphids of non-persistently transmitted viruses, the major route of plant virus spread in nature. As a proof-of-principle strategy, we made use of Agrobacterium tumefaciens to transiently express a hairpin RNA homologous to Potato virus Y (PVY) in plant tissues. A complete and specific interference with aphid transmission of PVY was achieved by inducers of RNA silencing, as demonstrated by specific siRNAs accumulation in agroinfiltrated tissues. To our knowledge, this is the first report of successful interference with non-persistent transmission of a plant virus using RNA interference.MV was supported by doctoral fellowships from CONICYT-BID (Chile). This work was supported by grant BIO2006-10944 from CICYT-MEC (Spain).Peer reviewed