Culturing Marker-free Transgenic Plants

Selectable marker genes, which were required for the efficient generation of transgenic plants, are useless once transgenic plants are produced. To overcome the safety concerns raised by selectable marker genes, several strategies, mostly through co-transformation, site-specific recombination and transposition, have been proposed to produce marker-free transgenic plants.The removal of marker genes will expedite public acceptance of transgenic crops. The progress in this field was reviewed.