Genetic transformation of Vitis vinifera L. cvs Thompson Seedless and Chardonnay with the pear PGIP and GFP encoding genes

Transgenic plants of Vitis vinifera L. cvs. Chardonnay and Thompson Seedless expressing the β-glucuronidase gene (GUS) and either the pear polygalacturonase inhibiting protein gene (PGIP) or the green fluorescent protein gene (GFP) were produced via somatic embryogenesis. Various media and culture conditions were tested in order to develop an efficient transformation method. Best results were obtained when embryogenic callus was initiated from anthers cultured on PIV medium and maintained in PT medium. Embryogenic lines of the rootstocks Saint George, 110 Richter and Freedom and from inflorescence primordia of Chardonnay and 110 Richter were also established using the same media. Inoculation with 109 cells·ml-1 Agrobacterium resulted in a higher number of selected calli than cultures inoculated with 107 or 108 cells·ml-1. Plants were regenerated in a modified WP medium from up to 46 % of the selected callus. Approximately 80 % of the lines expressed GUS and either PGIP or GFP but a low correlation was found between β-glucuronidase and polygalacturonase inhibiting protein activities.