Induction of a long-lived fusogenic state in viable plant protoplasts permeabilized by electric fields.

Electropermeabilized tobacco mesophyll protoplasts are shown to fuse by creating cell contact several minutes after electropulsation. Electropermeabilization was analysed by measuring calcein uptake. Experiments were performed at low temperature to avoid resealing of protoplast transient permeation structures. These results confirm that the long-lived permeabilized state induced by the electric field is associated to a fusogenic state, under viability conditions. This is indicative that as for mammalian cells, the electric field-induced membrane modifications, which give the permeable state, are such as to decrease the magnitude of the intercellular repulsive forces between plant protoplasts. Such a fusion method may be useful for somatic hybrids production with protoplasts showing morphological and physiological differences.