The epidemiological spread of many insect transmitted plant viruses involves molecular interactions between the virus and a population of cells in the insect host (vector). For successful interactions and virus transmission to occur, specific virus encoded proteins are critical determinants. Virus retention sites are also essential factors and their specific locations within the insect vary among different insect-plant virus systems. The overall HYPOTHESIS to be evaluated is that transmission of foregut-borne viruses, such as the whitefly transmitted viruses in the genus Crinivirus, is mediated by specific virus capsid component(s) and specific retention sites within the foregut of the insects. A novel immunofluorescent localization assay as well as biochemical and molecular approaches will be used to address the following SPECIFIC AIMS: 1) determine if a capsid component, the minor coat protein (CPm), of the crinivirus Lettuce infectious yellows virus (LIYV) can block the specific retention and transmission of LIYV, 2) determine the specific vector retention sites of the crinivirus Lettuce chlorosis virus (LCV), 3) determine if LIYV and LCV co-localize to similar sites in their common whitefly vector, 4) identify, through the use of engineered mutants, the molecular determinants of crinivirus retention and transmission, 5) determine the atomic structure of the LIYV CPm to precisely map the amino acid determinants involved in mediating virus retention and transmission. Results emanating from this project will provide insights into mechanisms underlying the whitefly transmission of criniviruses, and contribute to a broader understanding of virus-vector interactions. This will facilitate the design of blocking agents aimed at controlling the spread of viruses in the future. BROADER IMPACTS: The training opportunities made available through this project will enable trainees of different cultural and socio-economic backgrounds to benefit from the cross-disciplinary and technological/scientific expertise provided by the participating laboratories, as well as from NSF-affiliated programs, such as the CAMP Project, established at and supported by UC Riverside.
