Plating of isolated tobacco mesophyll protoplasts on agar medium

A technique was developed to derive cell and plant clones from isolated mesophyll protoplasts of tobacco. The protoplasts, plated on a fully defined agar medium, divided and grew actively forming visible colonies after one month of culture. Efficiency of colony formation depended on cell density and light condition during incubation. Under standard conditions, 60% of plated protoplasts formed colonies. Upon transfer onto suitable media, these colonies differentiated shoots and roots, and eventually regenerated whole plants. Advantages of mesophyll protoplasts as the source of clones as well as implication of the plating technique for genetical studies are discussed.