GENETIC-MODIFICATION OF THE COMMERCIAL APPLE CULTIVARS GALA, GOLDEN DELICIOUS AND ELSTAR VIA AN AGROBACTERIUM-TUMEFACIENS-MEDIATED TRANSFORMATION METHOD

Modern biotechnological techniques, including genetic modification, of fer important tools to plant breeders for the introduction of resistan ce genes into a fruit crop such as apple. However, the transformation methods necessary to generate transgenic apple plants from commercial cultivars are often tedious or unavailable. In this article we report on an Agrobacterium tumefaciens-mediated transformation method for the commercial apple cultivars Gala, Golden Delicious and Elstar. Souther n blot analysis confirmed the integration of both selection and marker genes, nptII and gus, with one or two copies per genome being present . For transformation, leaf segments were co-cultivated with a supervir ulent Aglobacterium strain, containing the nptII and gus genes. GUS-po sitive shoots were induced on calli which were able to proliferate-on kanamycin-containing medium. The transformation efficiencies, based on the number of GUS-positive shoots, were 0.7-8% per leaf explant for G ala, 0.2-6% for Golden Delicious and 0.4-0.8% for Elstar. The GUS-posi tive clones tested were able to form roots on kanamycin-containing med ium and developed into transgenic plants. The use of this transformati on method for the introduction of antimicrobial genes is discussed.