Rice, a More Nutritious Food Source

22/11/07 The advent of the cultivation of grains was a boon to humankind, giving humans a type of food that could be stored long term and would sustain them through drought and famine. Grains, however, lack many of the nutrients needed to sustain life.

A new research project co-led by Mary Lou Guerinot, the Ronald and Deborah Harris Professor in the Biological Sciences, is aimed at making rice -- which supplies an estimated quarter of the calories humans consume each day -- a more nutritious food source.

Guerinot is the project's a co-principal investigator. David Salt, a horticulture professor at Purdue University, is the principal investigator; and Shannon Pinson, a research geneticist at Texas A&M University and the U.S. Department of Agriculture, is co-principal investigator.

Some food is fortified with nutrients when it's processed, but very little of that food ever reaches the world's poor. By contrast, Guerinot and her colleagues want to find genes that help the plants take up more essential nutrients from their environment as they grow. This makes for not only a more nutritious food source but also a healthier and more resilient plant. "We feel biofortification is the way to go," she said. "Rather than add nutrients to the food after it's grown, we'd like them to enter the food as it grows."

Funded by a four-year, $5.5 million grant from the National Science Foundation, the group will first analyze some 1,800 different rice varieties for the presence of 18 elements, including those helpful to humans, such as iron, zinc, potassium, and manganese, and such harmful trace elements as arsenic, cadmium, and lead. They will make this information freely available to the research community.

The bulk of the research, however, will be a painstaking study of the varieties that are highest in iron and zinc, to identify the genes that are responsible for the uptake and storage of those elements. The group is focusing on these elements because billions of people suffer from iron or zinc deficiencies, resulting in stunted growth, impaired cognitive function, and other health problems.

Guerinot and colleagues have already successfully identified the genes responsible for iron uptake from the soil in Arabidopsis, a small flowering plant in the mustard family that is widely used as a model organism in plant biology.

In addition to possibly leading to the development of rice varieties that are higher in iron and zinc, the project could shed light on how plants turn on or off their ability to take up and store a whole array of elements, including harmful ones. This could be helpful to countries like Bangladesh, where rice is contaminated by the high levels of arsenic that naturally occur in the water. This knowledge also could help researchers seeking plants that can remove toxins from the environment.