Development of highly efficient genetic transformation protocols for table grape Sugraone and Crimson Seedless

Genetic engineering of grapevine is a powerful tool to study gene function as well as to introduce new traits into existing Vitis cultivars without altering their essential characters and identity. Agrobacterium-mediated transformation is one of the most efficient methods for gene transfer, but the efficiency of the procedure depends on several parameters such as the grapevine genotype, the selection strategy, the Agrobacterium strain, and concentration used to infect as well as the culture method among others. This chapter describes highly efficient genetic transformation protocols for seedless table grapevine cultivars Sugraone and Crimson Seedless by co-culturing embryogenic calli with Agrobacterium tumefaciens. The procedures are specific for each cultivar by adjusting the kanamycin concentration used to select transformed cells (20 mg/L and 50 mg/L kanamycin for Crimson Seedless and Sugraone, respectively) and the low Agrobacterium density used to infect the embryogenic calli (0.06 OD(600) being more effective for the transformation of Crimson Seedless and 0.2 OD(600) for Sugraone). Other factors that affect the transformation efficiency are the initial amount of embryogenic calli used to co-culture with Agrobacterium and the culture method of calli.