AGROBACTERIUM TUMEFACIENS-MEDIATATED TRANSFORMATION OF SHOOT-BUDS OF CHICORY

Vegetative propagation of chicory via axillary shoot proliferation is one of the best ways to obtain an offspring with complete genetic stab ility. These shoot buds were used in transformation experiments using Agrobacterium tumefaciens strains containing binary plasmids carrying the neomycin phosphotransferase gene (nptII) and the beta-glucuronidas e gene (uidA). Selection was carried out on basal medium containing 10 0 mg l(-1) kanamycin. Transformed plantlets were recovered at a freque ncy of about 10% within four weeks after co-cultivation. The presence of the uidA gene was demonstrated by transient gene expression experim ents using the histochemical GUS staining procedure. Evidence for stab le transformation was shown by subculturing leaf discs on kanamycin se lection medium, and Southern blot analysis confirmed the integration o f the nptII and the uidA genes in the plant genome. Analysis of the pr ogenies showed that kanamycin resistance was inherited as a single dom inant trait. This method for obtaining transgenic chicory plants repre sents an alternative to leaf disc transformation.