ENVIRONMENTAL RISK ASSESSMENT OF RELEASES OF TRANSGENIC PLANTS CONTAINING VIRUS-DERIVED INSERTS

Sequences derived from the genomes of plant viruses are being used to provide virus resistance in transgenic crop plants. Although the envir onmental hazards associated with the release of such plants have been discussed widely, it has not been possible to reach generally acceptab le conclusions about their safety. A case-by-case approach to the risk assessment of real examples is recommended as a means of building up confidence and of indicating areas of uncertainty. A logical framework for risk assessment is suggested, a key feature of which is identific ation of the viruses in the release environment that may infect the tr ansgenic plants. Each of these is considered in relation to each of th e three main classes of hazard (transcapsidation, recombination and sy nergism), and the risk associated with each event is analysed.