Molecular control of transgene escape from genetically modified plants

Potential risks of gene escape from transgenic crops through pollen and see d dispersal are being actively discussed and have slowed down full utilizat ion of gene technology in crop improvement. To ban the transgene flow, barr en zones and 'terminator' technology were developed as GMO risk management technologies in transgenic crops. Unfortunately, the technologies have not protected reliably the transgene migration to wild relatives. The present s tudy offers a novel molecular technique to eliminate gene flow from transge nic plants to wild relatives by recoverable block of function (RBF). The RB F consists of a blocking sequence linked to the gene of interest and a reco vering sequence, all in one transformable construct. The blocking sequence blocks a certain molecular or physiological function of the host plant. Act ion of the blocking sequence leads to the death of the host plant or to an alteration in its phenotype resulting in inability for sexual reproduction in nature. The recovering construct recovers the blocked function of the ho st plant. The recovering construct is regulated externally by a specific ch emical or physical treatment of the plants and does not act under natural c onditions. In nature, hybrids of the transgenic plants with its wild relati ves carrying the RBF will die or be unable to reproduce because of the bloc king construct action. A wet-king model of RBF is described in this report as one example of the RBF concept. This RBF example is based on ba, nase (t he blocking construct) and barstar (the recovering construct) gene expressi on in tobacco under sulfhydryl endopeptidase (SH-EP) and a heat shock (HS) promoter, respectively. (C) 2001 Elsevier Science ireland Ltd. All rights r eserved.