Variation among clones of Myzus persicae and Myzus nicotianae in the transmission of a poorly and a highly aphid-transmissible isolate of potato leafroll luteovirus (PLRV)

Fifteen clones of Myzus persicae (Mp) and two of Myzus nicotianae (Mn) were used to assess the aphid transmission of two isolates of PLRV characterize d as highly (HAT) and poorly (PAT) transmissible. Experiments conducted und er controlled conditions showed that the HAT isolate was very efficiently t ransmitted by all the clones tested. In contrast, an important aphid clonal effect was observed with the PAT isolate, with mean transmission rates by 15 clones being low (0-26%) and by the two others much higher (57 and 71%). Transmission values for each clone were shown to be stable over time and i ndependent of the kind of source plant used for acquisition, either infecte d Physalis floridana plants propagated by cuttings or grown from seedlings previously inoculated by aphids. These results lead to the conclusion that poor transmissibility cannot be related to intrinsic properties of either t he viral particles or the aphid clones on their own: the transmission proce ss and its specificity depend on interactions between both parameters.