Transient expression of the plasmid pCaMVCAT in plant protoplasts following transformation with polyethyleneglycol

Petunia and carrot protoplasts have been transformed with the plasmid pCaMVCAT by the use of polyethyleneglycol (PEG) as a facilitator. Transformation was revealed by the appearance of the chloramphenicol-acetyl transferase (CAT) enzyme within the tranformed cells. Maximal activity of the CAT enzyme was detected within 15 h following transformation, while after 60 h, its activity was significantly reduced, indicating transient expression of the CAT gene. The efficiency of transformation was highly dependent on the presence of CaCl₂ in the transformation system, was stimulated by non-functional carrier DNA and was independent on the molecular weight (MW) of PEG used.