Early flowering and genetic containment studies in transgenic poplar

Despite of the immense potential of gene technologies for tree breeding, release of genetic modified trees is still very rare. Biosafety concerns have hitherto limited application of gene technologies. The potential risks of transgenic trees, in particular transfer of recombinant DNA into the gene pool of a given species via vertical gene transfer, have been motive of concern. Biosafety research may allow avoiding potential risks of this technology. However, the evaluation of strategies for prevention of vertical gene transfer, probably the most important concern toward transgenic trees, has been hindered by the long time they require to reach the reproductive phase. We tested different strategies for promoting early flowering in poplar, aiming the development of a system for biosafety studies on gene containment. Early flowering poplar containing the 35S::LFY or HSP::FT gene constructs allowed first approaches for the faster evaluation of gene containment. However, some drawbacks, e.g., disturbed vegetative growth and flower development, still limit their potential application on biosafety research. A non-transgenic hybrid aspen showing a short vegetative phase was successfully used for the evaluation of the PrMA-LE1::STS sterility gene construct