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 Brazilian 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 contains marker genes for resistance to kanamycin and phosphinothricin plus the gene for the enzyme β-glucuronidase. A two step regeneration/selection procedure produced shoots of potato cultivar Mantiqueira with in vitro resistance to kanamycin and to phosphinothricin. After transfer to the greenhouse, the potentially transgenic plants, sprayed with the herbicide Finale(®) (20% a.i.; Hoechst(®)) remained green as compared to control clones that died immediately afterwards. Southern blot analysis and histochemical and fluorimetric assay for β-glucuronidase indicated that the gene coding for the enzyme was integrated in the potato genome and could be expressed in potato tissues. No success was obtained for transformation of cultivars Aracy and Baronesa using this procedure.