Organic misconceptions

Chemical mutagens and cobalt-60 radiation are very harsh mutagens, which typically cause dozens random mutations in seeds. “Breeders must pick through the mutants for traits they like, then try to get rid mid of many unwanted mutations as they can,” DellaPenna says.

“Recombinant DNA technology is actually more precise – we can now determine exactly where a transgene has gone into a chromosome, what other genes are in that region, and assess the likelihood that there might be unintended consequence on nearby genes.

“There is a misconception out there that organic foods are safer than genetically engineered foods. My view is that we would have the best of both worlds if we can develop GE crops to resist pests, fungus and viral diseases, and other types of problems, and grow them with minimal pesticides – or even organically, without pesticides – but that’s almost heresy.”

DellaPenna says micronutrient deficiencies were a problem in industrialised nations at the beginning of the 19th century, and were corrected by adding the missing nutrients. Fortifying foods like breakfast cereals with iron and vitamins, and, more recently, folate and omega-3 fatty acids, remains common practice.

“But we can’t do that in developing nations because of supply-chain problems,” he says. “You can grow a variety of vegetables to provide a balanced diet, but that’s simply unrealistic in most target populations, where staple crops account for between 50 to 95 per cent of total nutrient intake.”

The obvious solution is to make the changes directly in the foods, so the solution is delivered pre-packaged in the seed, not by supplementation.

“We can deliver folate in rice, and vitamin E, which may also help stabilise lipids in the rice grain and inhibit it from going rancid. Vitamin E is required for good immune function, and for cell-membrane integrity.”

DellaPenna says the required data are obtained by studying model systems to identify the genes involved in the various metabolic pathways. But in some cases, the approach will merely require directed breeding, using variant alleles of genes already present in the crop.

DellaPenna’s team, and other research groups, have dissected the carotenoid biosynthetic pathway and identified the genes involved – their work underpinned the achievement of Beyer and Potrykus in engineering “golden rice” to synthesise beta-carotene, using transgenes from bacteria and daffodil.

“Fifty per cent of the world’s population lives on rice, and if you want to make them sufficient in vitamin A and folate, the best solution is to engineer these pathways directly into the grain,” he says.

“But the bottom line is that we must improve the nutritional properties of our food crops as soon as we can, by whatever means we can.”