VRTP IMPACT - Virus-resistant transgenic plants: ecological impact of gene flow (UBC)

Duration: 2001-2004   




Framework 5: Quality of Life and Management of Living Resources

The objective of this project is to provide detailed evaluation of the two sources of potential genotypic impact that could result from large-scale cultivation of virus-resistant transgenic plants, and particularly ones expressing viral sequences.

Genotypic impact could result from two types of gene flow: one involving recombination between viral sequences transcribed from the transgene and the genome of an infecting virus, and another due to the potential for sexual outcrossing between the transgenic plant and a compatible wild species.

In both cases, this requires not only close examination of the interaction of the transgenic plants, on the one hand with the genome of other viruses, and on the other hand with related plant species, but also requires establishment of baselines on the role of these same processes in a non-transgenic context. Thus, the idea of impact as used here only concerns additional, i.e. above borderline, novel effects that could be caused by interaction of the transgenic plants with their biological environment.

In order to address these interlocking concerns, the VRTP IMPACT project has been divided into four Workpackages.Each of these will involve collaboration among several participants, and as a result, most of the participants are involved in more than one Workpackage.The first two workpackages (WPs I & II) are organised in a parallel fashion to evaluate the impact of recombination between transgene sequences and those of the genome of two particularly important groups of plant viruses, the potyviruses and the cucumoviruses, which are extremely different in both their biological and molecular properties, and thus may have different aptitudes for recombination in transgenic plants.WPs I & II will centre on comparisons of the outcome of recombination in transgenic plants with that in non-transgenic ones.Since our knowledge of the prevalence in nature of recombinant virus genomes is extremely sparse, this question will be address in a separate workproject (WP III) that will involve molecular epidemiology studies of virus populations in Spain, France.In WP IV, we will examine the impact of plant to plant gene flow from two major crop species where this is known to occur, rapeseed and beet. In both cases, this will involve field andglasshouse studies to evaluate if a virus resistance gene could confer a fitness advantage on the receptor wild or weedy species.