Regeneration from protoplasts—a supplementary literature review

Protoplast technology is important in, on the one hand, the application of various cellular methods in plant breeding (i.e. somatic hybridization, cybridization, direct DNA transfer via polyethylene glycol (PEG), electroporation, micro-injection), and various fundamental studies (e.g. on membrane transport, cell compartmentation, the cytoskeleton in relation to the cell cycle and cell division) on the other hand. For practical applications, plant regeneration from protoplasts is a prerequisite. In 1989, regeneration from protoplasts was listed (Roest & Gilissen 1989) for 214 higher plant species (Spermatophyta), representing 97 genera and 31 families. Since then, regeneration procedures for more than 100 higher plant species have been reported. These include many economically important agricultural and horticultural crops, as well as woody plant species. In this paper these new species are listed, supplemented with specific information on the donor tissue used, the culture technique applied, and the type of development of the regenerants. In addition, recent achievements in fundamental aspects of protoplast research, which gradually provide further insight into the genetical, physiological and ultrastructural background of the phenomenon of totipotency of plant cells, will be briefly reviewed.