Tulokset ja vaikuttavuus

Experimental part of the research project and the reporting of the results are in progress. Risk analysis part of the research project has been completed and the results will be reported as a scientific paper. Risk analyses have revealed that there is a huge amount of lacking basic information on the biology of GM-trees which makes thorough risk assessment of GM-trees difficult. In February, 2002, we organized a so called quided brain-storming with specialists from different fields of science to identify the hazards included in the open and contained use of GM-trees. The brain storming session was guided and the results of the session summarized by the risk management specialists from the Technical Research Centre of Finland, VTT. In general, a total number of the specified hazards varied between 50 and 70. When the hazards were categorized into specific groups, two groups of hazards were clearly dominant over the others, 1) the hazard of transgenes to spread into soil ecosystem throug h microbial processes, and 2) the hazard of transgenes to spread into nature through reproduction, i.e. through pollen and seeds. Later, we have organized several risk analysis sessions using different kinds of risk analyses methods directed to reveal the hazards included in the different steps of GM-tree production and cultivation. In the experimental part of the research, we have mainly focussed on the chitinase transgenic silver birches. In the greenhouse experiment, chitinase transgenic birches were found to be more resistant against fungal pathogen Pyrenopeziza betulicola than the control trees (Pappinen et al. 2002). The expression of a sugar beet chitinase IV gene in silver birch was observed to be stable during the 3 year field trial. According to field trial data, the expression of sugar beet chitinase did not increase birch resistance against leaf spot disease. Instead, some resistance against birch rust was achieved among some chitinase transgenic birch lines (Pasonen et al . 2004). At the same time when constitutive overexpression of chitinases is expected to increase plants’ resistance against fungal diseases, increased levels of chitinases may have harmful effects on beneficial chitin containing organisms, like symbiotic ectomycorrhizal fungi (EM). We have studied the effects of sugarbeet chitinase IV gene expression and 4 CL antisense transformation on mycorrhiza formation in chitinase transgenic and lignin modified silver birch seedlings in vitro (Pasonen et al 2004, Seppänen et al. 2004). Phylogenetic approach has been used to study the evolutionary history of chitinases and to investigate the usefulness of phylogenetic analyses as an information source for the risk assessment of chitinase transgenic silver birches. We have phylogenetically analysed silver birch chitinase amino acid sequences belonging to family 18 and 19 glycosyl hydrolases together with the other related sequences from the GenBank and determined which types of chitinases are pre sent in silver birch and studied their relationships to other chitinases. The resulting phylogenetic tree showed that very similar chitinases as type IV chitinase transferred from sugar beet (Beta vulgaris) to birch already exists in silver birch. Some bacterial chitinases from Streptomyces and Burkholderia, as well as a chitinase from an oomycetous fungus Phytophtora infestans grouped together with the class IV chitinases of plants, indicating ancient horizontal gene transfer events from plants to microbes (Lohtander et al. 2004).