Optimization of direct gene transfer in tomato

Abstract

The successful transformation of callus derived protoplasts of the tomato genotype MSK93 was recently described. Transformants were obtained with plasmid DNA containing the kanamycin resistance gene from Tn5 with expression signals from the nos gene as a selectable marker (plasmid pneoΔ18). In addition a (0. 8 kb) tomato sequence which promoted autonomous replication in yeast was cloned into pneoΔ18 resulting in pCTW22. Because thus far only a limited number of transformants were obtained (exclusively with pCTW22) and no diploid plants could be regenerated from these callus derived protoplasts, the transformation procedures were further optimized with leaf derived protoplasts of MSK93.