OGTR backs Hexima field trial

Melbourne-based agbiotech company Hexima will make a small piece of biotech history in October by becoming the first homegrown Victorian company to trial a genetically modified field crop.

The Office of the Gene Technology Regulator (OGTR) has approved Hexima’s application to field-test experimental GM cotton lines containing the company’s proprietary pest-protectant gene NaPI.

The contained field trials will be planted on a total of less than 0.5 hectares on two private farms on Queensland’s fertile Darling Downs agricultural region, west of Brisbane, over the next three cotton seasons.

Hexima director Dr Robin Heath, who was a member of the Melbourne University School of Botany team that cloned the NaPI gene from ornamental tobacco in the early 1990s, said the trials aimed to provide proof-of-concept for the efficacy for the efficacy of the proteinase-inhibitor strategy.

Heath said the NaPI strategy, if successful, could be used either as a back-up or an alternative to the Bacillus thuringiensis (Bt) genes currently used to protect commercial cotton crops in Australia, the US, India and South Africa against attack by the boll-munching larvae of heliothine months.

The Bt genes encode endotoxins that bind to receptors in the insect’s gut, causing the cells of the gut lining to die -- the insect starves to death. Heath said the NaPI gene induced starvation by binding to and deactivating the protease enzymes that allow the insect to digest plant proteins. Instead of being directly toxic to the caterpillar, NaPI arrests its growth and larval development by inhibiting its digestive processes.

Death is caused by slow starvation, or the starving caterpillars are more easily washed or blown off the plant by wind and rain, making them more vulnerable to arthropod predators and parasitoid wasps.

The gene technology regulator, Dr Sue Meek, has deemed that Hexima’s experimental cotton lines pose no risk to the environment or community health, so has waived the requirement for community consultation before the field trials proceed.

NSW, like Victoria, has a three-year moratorium on the commercial release of new GM crops, but the moratoria do not preclude field trials of OGTR-approved new crops.

However, Heath said Queensland was chosen for the contained field trial mainly because it was more accessible, via Brisbane, than the major NSW cotton-growing region around Narrabri, in central-northern NSW.

"We’re really happy to get approval, and we’re glad we chose cotton as our experimental crop," Heath said. "Cotton is a good choice because cotton farmers are very progressive in taking up new technology, and the community now accepts cotton as a well-regulated transgenic crop."

Heath said that while there was no evidence that the protease-inhibitor protein crop posed any human health hazard, and any edible oil from the crop would contain no transgenic protein, the OGTR would require further evidence of non-toxicity before the crop was approved for commercial release.

Clover trial also approved

The OGTR has also approved an application by Prof German Spangenberg’s research team at La Trobe University to conduct a contained field trial of a genetically modified white clover that has been made resistant to a common virus disease that reduces the productivity of clover pastures.

The field trial will be conducted over four years, at a single site in Victoria. The clover will be trialled under stringent containment, in an area of less than 500 square metres, and will not be allowed to be fed to livestock.

Unlike the cotton application, the clover field trial application was submitted to public comment before it was approved.