Cross-Talk Between Aphid Transmission, Long-Distance Transport, and Virion Assembly of a Closterovirus
Spread and survival of aphid-transmitted viruses depend on interactions between the virus, the vector, and the host plant. For phloem-limited viruses such as Beet yellows virus (BYV), aphid transmission requires virion assembly and transport in the plant vascular system. BYV genome encodes five proteins involved in the local movement, and an additional protein, p20, specifically required for the vascular movement. Strikingly, five out of these six proteins are also the virion components. Preliminary experiments indicated that p20 and two other virion proteins, p64 and CPm, are likely to play major roles in BYV aphid transmission. An infectious cDNA copy of the BYV genome will be used to screen the determinants of the long distance movement and aphid transmission in a Nicotiana benthamiana/Myzus persicae model. These screens will be facilitated
by the presence of a reporter gene, GFP, in the BYV cDNA clone, which permits visualization of infection by epifluorescent and confocal microscopy. Furthermore, an availability of the agroinfection allows us to uncouple processes of assembly, transport and transmission. We will dissect the pathway of BYV infection spread following aphid-mediated plant inoculation and identify the cells along the entire pathway. We will also determine the mechanisms responsible for the cross-talk between the long distance transport, aphid transmission, and virion assembly.