Designer rice brings nutrition to developing world

“I don’t eat white rice, it’s just empty calories”. So says the modern, health-conscious, weight-watching western urbanite.

But what if the choice between eating white rice and not eating white rice is a choice between living and dying? For billions of people in developing countries, this ‘high GI’, ‘over-processed’ grain full of ‘empty calories’ makes up 80 per cent of their diet, and they don’t get to choose what they eat.

White rice is packed with carbohydrates, which is a source of energy, but only contains small amounts of other vitamins and minerals. These ‘micronutrients’ are vital components of a healthy diet. The ‘big three’ micronutrient deficiencies in the developing world are of iron, zinc and Vitamin A. People who eat mostly rice, or another major cereal crop such as corn or wheat, are likely to be deficient in one or more of these. 

Iron deficiency causes poor mental development in children, depressed immune function and anaemia. Zinc deficiency also affects development and immune function, while Vitamin A deficiency is a major cause of blindness.

“If we can just improve the nutritional composition of these foods we could have a big impact,” says Dr Alex Johnson, from the School of Botany at the University of Melbourne.

Dr Johnson works on genetically modified crops. He did his masters and PhD at Virginia Tech helping to develop a GM potato that had natural resistance to a pest called the Colorado Potato Beetle. 

More recently he became interested in the role GM could play in improving nutrition among the world’s poorest people. So he turned his attention to iron.

He says traditional cross-breeding of rice varieties has failed to substantially lift the iron levels in rice.

“Back in 2007 I was looking at genes that transport iron in rice, which is a very complex process,” he says. “We found this one group of genes called NAS (Nicotianamine synthase) genes, and they control a lot of this process. If you just turn them up a bit higher you get rice plants that absorb more iron in the soil. They put about four times more iron into the grain.”

Gene expression is turned off and on by a region of the gene called the promoter. The promoters in the rice plant’s NAS genes only turn on when the plant is low on iron. Dr Johnson replaced the promoter region of one of the NAS genes with a promoter that is always on. This greatly increased the amount of iron stored in the plant, and in the rice grains. Coincidentally, this modification also assists with zinc uptake, and doubles the amount of zinc in the rice grains.

Dr Johnson and his team are currently half way through five-year field trials in Colombia and the Philippines. If these are successful, Dr Johnson hopes to release the crop to developing countries, with Bangladesh at the top of his wish list.

He has also developed wheat varieties that have twice as much iron and zinc as conventional varieties. He will shortly trial these in Western Australia, with his partners from the Australian Centre for Plant Functional Genomics.

One criticism of GM crops is that they are they are controlled by profit-making, multinational agri-businesses. Dr Johnson works on a different kind of business model. He wants to give it away for free.

He’s been working with non-profit group the Harvest Plus Challenge Program (which receives funding from the Bill and Melinda Gates Foundation) to develop and trial his crops, and is also working with World Vision Australia to identify and develop markets for his rice.

“I’ve just found that GM’s a really great way of improving nutritional composition of foods,” he says. “It’s fast, and it’s very targeted. We can take an existing crop and give it some vitamin A or give it some iron or some zinc, and it could have a big impact, it could affect billions of people.”

Iron and zinc enhanced rice is not the first GM rice crop. Vitamin A rich Golden Rice will soon be released in the Philippines, and Dr Johnson thinks Bangladesh will follow soon after.

He does not anticipate much opposition to the release of his rice in developing countries. 

“In Bangladesh, 60 per cent of women are iron deficient. So if you have a product that can provide you with enough iron in a rice-based diet, it’s hard to argue against that,” Dr Johnson says.

When plant breeders combine several new traits into a single plant, they call this stacking. “I would love to stack Golden Rice with high iron and high zinc,” says Dr Johnson, “because then you’ve tackled the three huge micronutrient deficiencies in developing countries.”

His ultimate wish is to make his product redundant.

“At the end of the day, the greatest thing would be to create that stacked product so that people will eat it and they become more healthy and then much more productive, so that national GDP increases and these people are wealthier and can afford a more diverse diet.

“One day it would be great to wean people off these mega-crops, so they don’t have to get 80 per cent of their calories from a single crop. But that’s not going to happen overnight. That’s going to take generations.”

www.botany.unimelb.edu.au