TRANSFORMATION OF POTATO (SOLANUM-TUBEROSUM) CV MANTIQUEIRA USING AGROBACTERIUM-TUMEFACIENS AND EVALUATION OF HERBICIDE RESISTANCE

In search of establishing a system for genetic transformation of Brazi lian potato cultivars, Agrobacterium tumefaciens carrying the plasmid pGV1040, was used to transform leaf discs of three cultivars of local importance, i.e., Aracy, Baronesa and Mantiqueira. This plasmid contai ns marker genes for resistance to kanamycin and phosphinothricin plus the gene for the enzyme beta-glucuronidase. A two step regeneration/se lection procedure produced shoots of potato cultivar Mantiqueira with in vitro resistance to kanamycin and to phosphinothricin. After transf er to the greenhouse, the potentially transgenic plants, sprayed with the herbicide Finale(R) (20% a.i.; Hoechst(R)) remained green as compa red to control clones that died immediately afterwards. Southern blot analysis and histochemical and fluorimetric assay for beta-glucuronida se indicated that the gene coding for the enzyme was integrated in the potato genome and could be expressed in potato tissues. No success wa s obtained for transformation of cultivars Aracy and Baronesa using th is procedure.