P-613 - Identification of grapevine host factors with pro-viral activity

Grapevine red blotch virus (GRBV) poses a threat to wine grape production. The lack of a suitable treatment necessitates the development of novel control strategies. During infection, virus proteins must interact with host proteins to carry out essential steps of infection. Disruptions in these protein interactions lead to the failure of viral infection. The first step to exploring these host genes as potential targets for gene editing is the systematic identification of pro-viral host factors. Our study focuses on identifying host factors of four GRBV proteins, C1 (replication associate protein), C2, C3, and C1:2 (full length replicase). Our approach used the yeast-two-hybrid system with viral proteins as baits, screened against a prey library of grapevine cDNA to identify interactors in vitro. The promising interactors of each bait protein will then be validated in planta using Bimolecular Fluorescence Complementation (BiFC) in microvine protoplasts. In vitro screenings of all four GRBV proteins have been conducted. From these screens, 8 promising host interactors of GRBV have been identified. Positive controls have been validated for the in-planta assay, and preparation of the experimental vectors has been initiated. Overall, identifying these interactors has generated insightful information about the strategy of GRBV to promote its replication and spread. This could provide a future roadmap for developing GRBV-resistance via gene editing.