Agrobacterium-mediated transformation of strawberry calli and recovery of transgenic plants.

Transformed calli and shoots of strawberry (Fragaria × ananassa Duch.) cv. Redcoat were obtained using Agrobacterium tumefaciens carrying plasmid pB1121. Inoculated leaf explants produced transgenic calli at a frequency of 3% on selection medium containing 50 μg/ml kanamycin. Twenty per cent of selected caili regenerated, giving rise to transgenic shoots. All transgenic calli and shoots expressed substantial amounts of GUS and NPT-II activity. The Southern blot analysis confirmed the insertion of both marker genes into the strawberry genome as single and multiple copy inserts. The transgenic shoots elongated on rooting medium in the presence of 25 μg/ml kanamycin, but exhibited reduced rooting ability.