Molecular Co-Chaperone SGT1 Is Critical for Cell-to-Cell Movement and Systemic Infection of Tomato Spotted Wild Virus in Nicotiana benthamiana.

Tospovirus is a tripartite negative stranded RNA virus and is considered as one of the most devastating plant viruses. Successful virus infection in plant requires many host factors. To date, very few host factors have been identified as important in infection in plants. We reported earlier that NSm protein encoded by (TSWV), a type species of the genus plays critical roles in viral cell-to-cell and long-distance movement. In this study, we determined that molecular co-chaperone NbSGT1 interacted with TSWV NSm in . TSWV infection significantly upregulated the expression of gene and transient overexpression of in leaves accelerated TSWV infection. In contrast, silencing the gene expression using a virus-induced gene silencing (VIGS) approach strongly inhibited TSWV NSm cell-to-cell movement, as well as TSWV local and systemic infection in plants. Furthermore, NbSGT1 was found to regulate the infection of both American and Euro/Asia type tospoviruses in plant. Collectively, our findings presented in this paper and the results published previously indicated that molecular co-chaperone NbSGT1 plays important roles in modulating both positive stranded and tripartite negative stranded RNA virus infection in plants.