Exploring the grapevine fanleaf virus RNA-dependent RNA polymerase-host protein interactome for insights into symptom development
Larissa Osterbaan: Cornell University
<div>Grapevine fanleaf virus (GFLV) is one of the greatest viral threats to grapevine cultivation worldwide. GFLV-infected hosts exhibit diverse symptoms, yet the molecular mechanisms underpinning symptom development remain largely unknown. This bipartite positive-sense RNA virus requires both genomic RNAs for systemic infection, which can be established in the model species <em>Nicotiana benthamiana </em>by agroinoculation using infectious cDNA clones. Most GFLV strains are asymptomatic in <em>N. benthamiana. </em>An exception is GFLV strain GHu, which causes a systemic vein clearing. Symptoms of GFLV-GHu are associated with a region near the C-terminus of the RNA-dependent RNA polymerase (1E<sup>Pol</sup>). Using targeted mutagenesis, we recently showed that vein clearing symptom can be abolished, without affecting virus infectivity, by modifying a single codon in the 1E<sup>Pol</sup> coding region. Furthermore, we demonstrated that symptom development is dependent on amino acid identity, not nucleotide sequence, at this site. To further explain the mechanisms of symptom development, we hypothesized the existence of a specific GFLV-GHu-<em>N. benthamiana</em> protein interaction network. Mapping the 1E<sup>Pol</sup>-host protein interactome will provide insights into the molecular context of this protein central to GFLV replication and allow us to determine host interactants unique to GFLV-GHu, which may be associated with vein clearing symptom development in <em>N. benthamiana</em>.</div>
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