Maize gene-modified to resist insects being monitored for risk in South Africa

by Hopewell Radebe

The job of opponents of genetically modified products has just become more difficult.

Scientists have developed a new generation of insect-resistant maize and have promised that the achievement comes with a "framework for environmental monitoring" to ensure there is no unintended effect on the land and other plant species, according to the South African National Biodiversity Institute.

Previously, pesticides were used to control pests on maize, but widespread usage had an adverse effect on the environment and human health.

The joint research project — involving the Department of Environmental Affairs and Norway’s Directorate of Nature Management , and co-ordinated by the institute — has led to the development of genetically modified maize with a transgene from Bacillus thuringiensis (Bt), which produces a toxin to manage a specific maize pest.

The report on the outcomes of the five-year SA-Norway environmental biosafety co-operation project was released last week .

Lukeshni Chetty, deputy director of the genetically modified organism unit at the institute, says that while the framework for genetically modified maize is relevant to the monitoring of insect- resistant maize, it also represents a blueprint for research and monitoring of other genetically modified crops in SA.

"This will go a long way towards strengthening and supporting the regulatory framework governing genetically modified organisms in the country, and will contribute to the responsible and sustainable use of this technology in meeting national imperatives," she says.

The report argues that globally all genetically modified products undergo stringent risk assessments prior to commercialisation, "however, there exists the possibility of unintended risks occurring." These can only be identified and investigated after commercial release. The project sought to identify these post-release risks.

The investigated risks included the effect on target and non-target organisms — the effect on the pests and other organisms in the maize cultivation ecosystem — and the effect on soil organism biodiversity, as well as the gene flow and its subsequent contribution to the development of insect resistance.

Ms Chetty says some key scientific research outcomes from this project include toxin levels which varied between plant tissues and plant-to-plant toxin transfer and influences. This variability in toxin production could contribute to resistance development, as insects may be exposed to sublethal dosages and thus become immune to the product.

The researchers also monitored the gene flow from Bt maize (maize with the toxin) to non-Bt maize (maize without the toxin) through cross-pollination, which often resulted in the production of low levels of Bt toxins, another potential contributor to development of resistance .

Resistance to the toxin has previously been detected in the Northern Cape, and another Bt-resistant population was recently recorded in North West . This suggests that such resistance has the potential to spread to other provinces .

SA is the largest producer of genetically modified food in Africa and the eighth-largest in the world after the US, Brazil, Argentina, India, Canada, China and Paraguay. Burkina Faso and Egypt occupy second and third place in Africa . At least 25 countries already plant genetically modified organisms .

In 2009, almost half (46%) of the global area planted with genetically modified organisms was in developing countries. It is expected that by 2015, this will increase as more developing countries take their cue from industrialised nations and adopt genetically modified crops.

The project partners include the Centre for Biosafety in Norway, North-West University, the University of Fort Hare and the University of the Free State.

The project’s results will allow researchers to provide proper estimates of yield, production costs and pest management, all of which affect the maize market and the cost of maize and maize products.

Businessday