Introduction of foreign genes into Pharbitis nil calli using a vector derived from Agrobacterium pTi.

Transgenic calli of Pharbitis nil which grow in the presence of kanamycin were obtained by introduction of plasmid pBI121, which carries kanamycin resistance and the gene for beta-glucuronidase. The calli were shown to have fragments of vector DNA in their genome and high levels of beta-glucuronidase activity. This is the first report of the introduction of T-DNA into P. nil and the T-DNA has been shown to be integrated without apparent rearrangement in its genome. The range of copy numbers was between 3 and 5. The beta-glucuronidase activities measured were about 10 times higher than those of transgenic tobacco by introduction of the same plasmid as previously described by Jefferson et al. (1987). Thus, the widely used CaMV 35S promoter also appears to be very active in P. nil.