Key issues in the deliberate release of genetically-manipulated bacteria
The deliberate release of a genetically engineered bacterium often requires that a complex pathway be travelled through scientific and regulatory questions. It is important to consider the scientific aim of the release and the nature of the modification (deletion or insertion, site of insertion, level of expression) and its likely effect on survival of the organism and the possibility of gene transfer. In Australia, the Genetic Manipulation Advisory Committee assesses applications and makes recommendations about pre-release testing and procedures for conducting field release. Two examples of field release of genetically manipulated bacteria in Australia are considered. Firstly, the commercial product Agrobacterium strain K1026 (‘NoGall’TM), a genetically engineered biological control agent for crown gall disease of stone fruits and roses. Secondly, a lacZY-marked derivative of a strain of Pseudomonas corrugata, that can act as a biological control agent against take-all disease of wheat. Prior to release, bacterial survival and competition was tested in soil microcosms. The distribution and survival of the organism were monitored after field release. Since 1992 the marked bacteria have been recovered only after enrichment. Assessment of risk should consider the survival and spread of the genetically manipulated bacterium and its foreign DNA and the impact of the inoculated bacteria on other (‘non-target’) organisms.