Exogenous application of double-stranded RNA to reduce grapevine Pinot gris virus titre in in vitro grown Vitis vinifera

A method of delivering short synthetic double-stranded RNA (dsRNA) to stimulate RNA interference (RNAi)-mediated control for grapevine Pinot gris virus (GPGV) in grapevines was developed and evaluated in this study. The dsRNA molecule targeting the RNA-dependent RNA polymerase (RdRp) gene of the GPGV genome was designed and produced by a twostep polymerase chain reaction (PCR) approach followed by in vitro transcription of the amplicon. A significant decrease in virus titre was observed seven days after dipping shoot tips of GPGV-infected tissue culture (TC) plantlets into a solution of GPGV-RdRp-dsRNA followed by re-introduction to TC. The effect was more pronounced in shoot tips dipped in the GPGV-RdRp-dsRNA solution for 24 hours than in tips dipped for two hours. This study represents the first successful demonstration of dsRNA-mediated control in TC plantlets for GPGV and offers a promising avenue to provide virus-free material to nurseries, contributing to the overall health and sustainability of the viticulture industry.