The long term goal of the proposed research is to understand the interactions which regulate a synergistic virus infection. Experiments focus on synergistic interactions between potato virus X (PVX) and any of several related viruses from the potyvirus group of plant viruses. The PVX/potyvirus synergisms are characterized by a large increase in the level of PVX in co-infected cells as compared to cells infected with PVX only, but no corresponding increase or decrease in the level of the potyvirus. Our recent work indicates that the regulation of PVX RNA replication is altered in the synergistic co-infections. The main focus of this proposal is to delineate the potyviral sequences which regulate various aspects of the PVX/potyviral synergism using stable transformation experiments in whole plants and in synchronously infected protoplasts. A further aim is to clarify the role of long distance viral movement in localization of the acute synergistic response. %%% Recent studies have shown similarities in diverse plant and animal viruses based on genome organization, mechanisms of gene expression, and sequence homology of virally encoded, nonstructural proteins. These results suggest that elucidation of molecular mechanisms for virus interactions obtained in one system may well apply to a diverse group of other virus systems.
