IRRI begins trials on GM iron-rich rice combat nutrition deficiency

Scientists have made a breakthrough in developing a rice variety rich in iron and zinc, brightening the prospect of combating nutrition deficiency among millions of people in poor countries across Asia.

Iron and zinc are the most common mineral nutrients needed for a balanced human diet. It would take 10 years before the new rice variety could be released for human consumption, because of the need for evaluation in the field over several seasons, and the need for bioavailability studies to discover whether animals actually absorb the iron.

In view of this, field trials have begun at the Philippines-based International Rice Research Institute (IRRI). "The genetically-modified (GM) rice has up to four times more iron than conventional rice and twice as much zinc," said Alex Johnson from the Australian Centre for Plant Functional Genomics (ACPFG).

"The rice has some of the highest iron concentrations that have been described for white rice (up to 19 parts per million). We have also demonstrated that the iron is in the endosperm tissue that makes up white rice," Johnson said. This is important because of the widespread consumption
of white rice.

HarvestPlus, which promotes biofortification research, usually focusses on conventional plant-breeding methods. But increasing the level of iron in rice is hard to achieve through conventional breeding because there are few naturally occurring varieties of rice with higher concentrations of iron to kick off the breeding process.

Johnson and his team focussed on nicotianamine, a substance that occurs naturally in rice and helps it to take up iron from the soil. Normally, it is the low levels of iron in the soil that signal the rice to switch on the genes that control the production of nicotianamine. The scientists have succeeded in keeping these genes switched on all the time. The method also boosted zinc levels. Since nicotianamine naturally occurs in rice, consumption was unlikely to have any adverse health effects.