Thidiazuron-induced regeneration and genetic transformation of grapevine rootstock varieties

In vitro regeneration from cell to plant, a technique considered to be an important precondition of gene transfer, was attempted in 12 grapevine rootstocks starting with anthers of the plants as inocula. Embryogenic callus was induced in solid Murashige-Skoog medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and thidiazuron (TDZ). Five of the tested rootstock cultivars (Borner, Richter 110, SO 4, St. George and Teleki 5 C) yielded embryogenic callus lines that regenerated entire plants. From these cultures Richter 110 and St. George varieties produced transgenic plants following Agrobacterium -mediated transformation with an nptII/gusA gene construct using a simple, but effective cocultivation protocol. The putative transgenic lines expressed the gusA gene. The T-DNA transfer and integration was confirmed by PCR analysis.