AILV-V is unable to revert GFP silencing while interferes with cell-to-cell movement of silencing signal.

<p>In <b>A,</b> progression of GFP silencing (indicated by dark red areas along the major veins) in a plant of <i>N. benthamiana</i>, line 16c, at 14 dpi with the TMV-GFP vector. Silenced areas were inoculated with AILV-V but no desilencing effects were observed at 30 dpi with AILV-V; rather the silenced areas expanded (in <b>B</b>) following the spread of TMV-GFP infection. In <b>C</b> Free GFP was expressed transiently in 16c <i>N. benthamiana</i> from the binary vector pBIN-mGFP4 carried by <i>A. tumefaciens</i>. Prior to agroinfiltration, leaves were mock-inoculated with buffer (Mock) or with AILV-V (AILV), PVY-SON41 (PVY), AILV-V and PVY- SON41 (AILV+PVY) and PVA-B11 (PVA). Upon ectopic expression of GFP, a thin border of dark red tissue was visible at 14 dpi in plants mock-inoculated indicating short-range movement of GFP silencing. This border was not produced in leaves of plants inoculated with AILV-V, suggesting a viral interference with cell-to-cell movement of the silencing signal. Green fluorescent areas visible in AILV+PVY, PVY and PVA infected plants indicate suppression of silencing driven by VSR coded by PVY-SON41 and PVA-B11.