Genetically modified trees: Utilisation and risk assessment

Summary

Over the past 80 years, considerable effort has been directed at tree improvement through conventional breeding. Mass selection and reselection based on progeny testing have yielded large genetic gains for chosen traits and allowed the establishment of seed orchards representing successive stages of improvement. Plantation forestry, based on successful breeding of superior tree genotypes, is becoming more widely used by international forestry companies, since it offers the possibility to grow and manage forests of high economic value and superior quality. A wide range of tree species such as poplars (Populus spp.), willows (Salix spp.) and sugi (Cryptomeria japonica) have been vegetatively propagated for centuries.

Nowadays tissue culture methods facilitates large-scale propagation of genotypes for research (for ex. genetic transformation) and practical applications such as breeding and reforestation. Culture methods for the endemic aspen, birch and spruce in Finland are already so well developed that routine and large scale propagation for reforestation is presently done with aspen and hybrid aspen and has been done in the recent past with birch. In both agriculture and forestry, DNA markers have been employed to identify elite genotypes and detect genomic regions relating to important traits.

It is not surprising that with an increasing world demand for pulp, paper and timber products, along with the growing awareness of the high ecological and social value of indigenous forests, more efforts have been directed at molecular tree improvement for plantation forestry. Genetic engineering in forestry has become a reality and the first transgenic trees are in the field (for ex. In Finland, New Zealand, USA etc.) for evaluation of gene expression, growth performance and the change of lignin composition.

The limited availability of solid biological data creates one of the most difficult challenges in the risk assessment of GMO (genetically modified) plants. As a whole, successful risk assessment of GMOs is bound to require an interdisciplinary approach, utilising knowledge from many different fields of science (molecular biology, gene technology, evolutionary biology, various disciplines of ecology, agriculture, etc.)

One way of meeting these challenges is to examine the problem by utilising systematic risk analysis procedures. Aim of our study is to use genetically modified trees for analysing biochemical pathways leading to important traits and to develop methods and knowledge for the risk assessment of genetically modified forest trees.