Acquisition and Retention of Potato virus Y Helper Component in the Transmission of Potato aucuba mosaic virus by Aphids

Potato aucuba mosaic virus (PAMV) is transmissible by aphids in a non-persistent manner but only in the presence of a Potyvirus helper component (HC) such as that of Potato virus Y (PVY) that must be acquired beforehand or simultaneously. To compare the acquisi- tion and persistence of PAMV and PVY-HC, the PVY- HC was acquired ®rst and then PAMV. The acquisition access and post-acquisition fasting periods were varied. The results show that PAMV and PVY particles, and also PVY-HC could be acquired in 10 s. Some PVY-HC activity could be detected in fasting aphids at least 6 h after acquisition whereas PAMV infectivity was retained for only 2 h. These ®ndings are compatible with the non-persistent transmission concept being controlled by enzymatic release of PAMV particles bound to aphid mouthparts by PVY-HC.