Ti Plasmid Homologous Sequences Present in Tissues fromAgrobacteriumPlasmid-transformedPetuniaProtoplasts

摘要

Suspension cell protoplasts of albinoPetunia hybridahave been transformed by isolatedAgrobacterium tumefaciensTi plasmid. Uptake of octopine Ti plasmid (pTiACH5) into protoplasts was stimulated by poly-L-ornithine and polyethylene glycol (PEG). The frequency and efficiency of transformation of protoplasts to phytohormone autotrophy was compared using the two uptake agents with various concentrations of plasmid. Transformation was most efficient with PEG-mediated uptake, 5μg of Ti plasmid per 106protoplasts giving a frequency of 6×10−5. Octopine was not synthesised in any of the transformants after the second subculture on hormone-free medium. DNA-DNA hybridisation showed the presence of DNA homologous to the T-DNA region of pTiACH5 in all clones analy