The Gene Technology Act 2000 (the Act) and the Gene Technology Regulations 2001 (the Regulations) set out requirements which the Gene Technology Regulator (the Regulator) must follow when considering an application for a licence to intentionally release a genetically modified organism (GMO) into the environment.
For a licence to be issued, the Regulator must be satisfied that the release will not pose any risks to human health and safety or the environment that can not be managed. To this end, Section 51 of the Act requires the Regulator to prepare a risk assessment and risk management plan (RARMP) for each licence application, in consultation with a wide range of expert groups and stakeholders.
The University of Queensland (UQ) applied for a licence (application number DIR 026) for the limited and controlled release of genetically modified (GM) papaya in the Shire of Redlands, Queensland. Seven lines of GM papaya have been modified to delay the process of fruit ripening, while an eighth line contains a ‘reporter’ gene that will allow evaluation of the operation of the gene regulatory elements used in the other GM papayas. Up to 300 plants of these eight GM papaya lines will be grown in an area of one hectare, from June 2003 to December 2006.
Papaya fruits have poor storage qualities and delayed ripening may prevent spoilage during transportation and storage. Six of these GM papaya lines have modifications which are expected to decrease production of the plant hormone ethylene, which is the ‘trigger’ for initiation of the ripening process in papaya fruit. The seventh of these GM papayas has a modified ethylene receptor, expected to reduce sensitivity to ethylene. All seven GM papaya lines are expected to exhibit delayed fruit ripening.
All of the GM papayas also contain bacterial antibiotic resistance genes, which were used solely to aid in selection of genetically modified cells in the initial laboratory stages of development of the GM papayas.
The applicant will gather key information from the release about the effect of the genetic modification and the function of the inserted genes. The UQ indicated that these data could not be generated without a field release as fruit production is not possible in glasshouse-grown papaya trees, which can grow to several metres in height before reaching reproductive maturity. However, the release will be strictly limited and controlled. The GM papaya plants in the release will be grown within a self-supporting ‘insect-proof’ enclosure†, which will also prevent access by animals. None of the papaya plants from the release, or their by-products, will be used for human or animal feed. Fruit and some other plant tissues generated in the release will be analysed in the laboratory for physiological, nutritional and quality attributes and for expression of the inserted genes.
Two limited and controlled releases of GM papaya were approved in Australia under the previous voluntary system that was overseen by the Genetic Manipulation Advisory Committee. These releases received ‘deemed’ licences under the new regulatory system that are due to expire on 21 June 2003. There have been no reports of adverse effects on human health or the environment resulting from these releases of GM papaya.
Licence application DIR 026/2002 covers three of the lines that were previously authorised for release (PR-128) at this site. The issuing of a licence in respect of this application enables the continued evaluation of 20 plants of these three lines, as well as the release of up to five new lines of GM papaya.
The evaluation process
Licence application DIR 026/2002 from the University of Queensland has been evaluated, and a risk assessment and risk management plan (RARMP) prepared, in accordance with the Act and the Regulations, using a Risk Analysis Framework. This framework was developed by the Regulator in consultation with the public and key State, Territory and Commonwealth government stakeholders and the Gene Technology Technical Advisory Committee, and is available at www.ogtr.gov.au/pdf/public/raffinal.pdf.
Details of the process that the Regulator must follow, including the prescribed consultation process on the application, and the matters that must be considered in preparing a RARMP, are set out in Appendix 6 of the RARMP. The complete RARMP can be obtained from the OGTR or from the OGTR’s web site at www.ogtr.gov.au.
The risk assessment considered information contained in the application (including information required by Act and the Regulations on the GMO, the parent organism, the proposed dealings and on potential impacts on human health and safety and the environment), submissions received during consultation and current scientific knowledge.
Through this process, potential hazards to human health and safety or the environment that may be posed by release of GM papayas were identified. These have been evaluated on the basis of the likelihood of each hazard occurring and the likely impact of the hazard were it to be realised. The identified potential hazards relate to:
toxicity or allergenicity to humans and other organisms: could the GM papayas with delayed fruit ripening or reporter gene expression be more toxic or allergenic than non-GM papaya, as a result of the novel gene products or because of unforseen or unintended effects;
weediness: could the GM papayas be harmful to the environment because of inherent weediness or increased potential for weediness; and
transfer of introduced genes to other organisms: could the new genes introduced into the GM papayas transfer to non-GM papaya or to other organisms, with adverse consequences.
Conclusions of the risk assessment
The Regulator considers that the limited and controlled release of GM papayas with delayed fruit ripening or reporter gene expression will not pose a significant risk to public health and safety, or to the Australian environment, that cannot be managed. The assessment of each potential hazard identified above is summarised under a separate heading below.
The GM papayas are unlikely to prove more toxic or allergenic to humans or other organisms than conventional papaya, because none of the introduced proteins, or the native proteins with modified expression in the GM papaya, have any known intrinsic toxicity or allergenicity. However, detailed toxicity and allergenicity studies have yet to be conducted. Food Standards Australia New Zealand (FSANZ) is responsible for human food safety assessment, and FSANZ approval would need to be obtained before these GM papayas could be used in human food. Currently, the applicant has not applied to FSANZ for evaluation of material from the GM papayas for use in human food.
The risk of GM papayas establishing as a weed is low and not likely to be greater than that of conventional papaya. Papaya is not a problematic weed of either agriculture or of natural ecosystems and the genetic modifications are unlikely to alter those aspects of papaya’s biology that may potentially affect its weediness. Other than human transportation of papaya fruit, the most likely means of C. papaya being dispersed in the environment is by flying foxes (Poliocephalus spp.), a known pest of papaya plantations. The use of an insect-proof enclosure, as proposed by the applicant, will prevent flying foxes and other animals from accessing the GM papayas.
Transfer of introduced genes to other organisms
Gene transfer from the GM papayas to non-GM papaya is possible by pollination. The most likely means by which pollen could be transferred to other plants is via hawkmoths (Lepidoptera: Sphingidae), which are the only significant pollinators of papaya in Queensland. The use of an insect-proof enclosure, as proposed by the applicant, will minimise the potential for pollen movement by pollinators. Thus, the risk of gene transfer from GM papayas to cultivated papayas is negligible.
The likelihood of transfer of the introduced genes to other organisms (including microorganisms) is negligible, but even if such transfer occurred, it would be unlikely to pose any hazard to human health and safety or the environment, as the introduced genes are naturally present in microorganisms or in papaya.