Inducible promoters for marker gene elimination using the Cre/lox recombination system

The production of genetically modified plants usually requires the use of marker genes that enable the targeted selection of transformed cells and their regeneration into whole plants. These are usually antibiotic resistance marker genes (ARMG), which are, however, irrelevant for the possible practical use of the plants after successful regeneration.

As part of a joint project of the Federal Ministry of Education and Research (BMBF) on the subject of "Optimizing the biological safety of transgenic plants", the cre/lox recombination system of bacteriophage P1 was tested at RLP AgroScience for the elimination of ARMG on vines. For this purpose, a vector system was developed that makes it possible to remove ARMG after transformation and regeneration by means of induced activity of the Cre recombinase. The special feature is that the cre gene cassette localized together with the ARMG on the vector is also removed from the genome by a sequence-specific recombination event, controlled by an external stimulus (autoexcision). Various inducible promoters have been and are being tested for this control.