Scientists have tripled the iron content of rice by inserting a soybean gene into the plant's DNA. The achievement, reported in the March issue of Nature Biotechnology, could help alleviate anemia in the estimated 1.3 billion people who don't get enough iron to stay healthy.
Anemia causes a host of ills, including brain damage in infants, increased susceptibility to infection, and chronic exhaustion. Poor people in developing countries suffer the highest rates of anemia, because their diet mostly consists of grains containing little iron, and they can't afford to buy dietary iron supplements.
Looking to fortify vegetables with iron, scientists at the Central Research Institute Electric Power Industry in Japan hit on the idea of putting the gene for ferritin, a protein that collects iron, into a common strain of Asian rice. Produced by many animals, some plants, and bacteria, ferritin can clutch up to 4500 iron atoms in its central storage cavity. Plant molecular biologists Fumiyuki Goto, Toshihiro Yoshihara, and their colleagues first isolated the ferritin gene from soybean sprouts, and then used a soil bacterium to transfer the gene into the DNA of rice cells. The researchers inserted the gene for ferritin next to a rice gene called glutelin, which turns on only during seed production. This ensured the rice would make ferritin and store iron only in its seeds.
To their delight, the scientists found that the transgenic rice not only made working ferritin, but stored three times more iron than normal rice, exclusively within the seeds. One meal-sized portion of the iron-rich rice supplies half of an adult's daily iron requirement. What's more, the gene jockeying did not harm the plants. Since half the world's population relies on rice as a daily staple, the researchers hope iron-rich rice could someday take a big bite out of a major malnutrition problem.
The ferritin rice work heralds a coming age of "designer crop plants" packing a hefty nutritional punch, predicts Michael Sussman, a plant molecular biologist at the University of Wisconsin. However, gourmets might want to wait a little bit before filling their rice bowls. "We have never tried to eat the ferritin rice," concedes Yoshihara, "so we don't know about the taste."