Recent analyses of the luteovirus and related PEMV group have identified a capsid subunit implicated as the determinant of circulative aphid transmission. It is hypothesized that the recognition between virus and vector is mediated by specific receptors occurring in the aphids' salivary system. THe objectives of this study are twofold. First, it is proposed to apply sequence analysis of transmissible and nontransmissible strains of PEMV to examine the mechanism of expression and suppression of this phenotype. Second, the specificity of the virus-vector interaction will be exploited to produce specific probes for application in EM in situ localization studies to identify the site(S) within the vector leading to this recognition. This research concerns the molecular basis of aphid transmission of a group of economically important plant viruses known as the pea enation mosaic viruses. This study will provide information on the viral protein domains involved in aphid transmission of the virus, and the genetic mechanisms that lead to the expression of specific viral phenotypes. In addition, it will provide information on the pathway of virion transport, as well as on the presence and location of viral receptors in the aphid vector. Since there is currently no known plant resistance mechanisms for these viral groups, understanding this transmission process may suggest methods for both vector and virus control.
