Further evidence for the transformation ofVinca rosea protoplasts byAgrobacterium tumefaciens spheroplasts.

Protoplasts ofVinca rosea were transformed by spheroplasts ofAgrobacterium tumefaciens harboring nopalinetype Ti plasmids according to the procedure of Hasezawa et al. (1981). These transformants frequently differentiated tracheids, but further differentiation to teratomata has not so far been observed. Transformation was confirmed by the improved detection of nopaline synthase, where the sensitivity and specificity of the enzyme reaction was increased by employing(14)C-α-ketoglutaric acid and(3)H-arginine as substrates. The nopaline synthase activity was identified by the comigration of these two radioisotopes in the cnromatogram. Furthermore, the T-DNA structure of one of these transformants was examined by Southern hybridization according to Thomashow et al. (1980) and compared with that ofVinca rosea crown gall.