Munich

The multinational company Novartis Seeds last week launched a campaign to gain worldwide support from the plant-science community for its new marker-gene system, Positech.

The campaign follows the company's recent announcement that it plans to phase out antibiotic-resistance marker genes in its future products, in an attempt to restore public confidence in the safety of genetically modified foodstuffs.

Plant geneticists use marker genes to monitor the transformation of plant cells after a foreign gene has been introduced into a plant along with the marker. The most commonly used markers are antibiotic- or herbicide-resistance genes, which protect the cells against an agent introduced to kill those that have not taken up the desired DNA.

But concerns have been triggered about the potential threat to public health. There are fears that antibiotic resistance genes could ‘jump’ from transgenic plants to microorganisms such as gut bacteria, increasing antibiotic resistance in humans.

The Positech marker system uses transformed plant cells that contain the gene encoding the enzyme phosphomannose isomerase (PMI). In the selection process, only the cells that take on the PMI trait can survive in a culture in which they are fed only mannose, a simple sugar. Novartis says the system has been tested successfully with transgenic maize and wheat.

“Positech is well along on the development path,” Wally Beversdorf, head of research and development at Novartis Seeds, told last week's International Crop Sciences Congress in Hamburg. “We will have regulatory packages containing PMI probably within 12 to 18 months.”

Basic researchers, who can use ‘Positech’ without royalties, have welcomed the launch. “The availability of less controversial marker genes would certainly improve the acceptance of our research, and cool down the public debate,” says Uwe Sonnewald, head of molecular cell biology at the Institute for Plant Genetics and Crop Plant Research in Gatersleben, Germany.

But environmental groups say that phasing out antibiotic-resistance marker genes would only be a small improvement. Greenpeace has called Novartis' campaign “mere propaganda” aimed at easing consumer concerns about genetically modified foods. “Other important issues, such as the ecological impact of gene transfer into the environment, are ignored,” says a spokesman.