Cocultivation Techniques - A further technique which would be useful when transferring DNA present in bacteria to higher plant cells involves the direct fusion of bacterial and plant cells. Its key components are:

(1) rapid culture method,

(2) optimal conditions for cocultivation of A. tumefaciens cells with protoplasts, and

(3) selection for hormone autotrophy.

Using the cocultivation technique adapted to the rapid plating system and early selection for hormone autotrophy, transformation frequencies as high as 80% have been observed with A.

tumefaciens strains carrying octopine, nopaline or agropine type Ti plasmids.