Virus -host interactions in alfalfa mosaic virus-Arabidopsis thaliana pathosystem

Hosts amenable to studies at the molecular level are currently not available to identify host genes involved in AMV infection. So, we identified and characterized Arabidopsis as a host for AMV. Sixty five ecotypes supported AMV infection, while 3 could not be infected. However, none of the susceptible ecotypes displayed any characteristic symptoms. AMV infection in Col-0 ecotype, which supported vigorous systemic infection and accumulated higher levels of AMV than in the symptomatic host Nicotiana tabacum, was further characterized by using infectivity assays, electron microscopy, and protoplast assays. Using two hybrid assays, candidate Arabidopsis proteins that interacted with AMV coat protein were identified. Some of the putative interacting partners have been implicated in other virus infections and hence constitute primary candidates for confirmation in in vitro and in planta pull-down assays. To do that, we developed many tools including affinity-tagged recombinant proteins and antibodies. One candidate CP-host protein interaction was also demonstrated in vitro by using pull-down assays. Yeast two-hybrid assays also identified one Arabidopsis protein that interacted with the methyltransferase domain of the AMV P1 protein