Cadmium is a metal which can accumulate in rice, especially rice grown in irrigation water contaminated by mining or other industrial operations, and chronic exposure can lead to cadmium poisoning causing softening of the bones and kidney failure. Shimpei Uraguchi, in the Fujiwara Group at the University of Tokyo, has discovered a gene which transports cadmium, and by controlling the expression of this gene, the cadmium concentration levels in rice can be reduced by about 50%.
"For cadmium taken in from sources other than food, international standards have been set. Compared with those standards, the average cadmium intake of Japanese people is known to be high. It's also been found that most of that cadmium intake comes from eating rice."
"The newly discovered gene in rice resembles one found in wheat. The similar gene found in wheat is known to carry positive ions such as cadmium and calcium. We started our research by wondering if that kind of gene was also present in rice."
In this research, it was found that when cadmium taken up through the roots made its way into the grains of rice, the transport occurred through the action of a positive ion called OsLCT1.
Once this was discovered, the researches controlled the expression of this gene in whole-grain rice through genetic modification. By doing this they succeeded in reducing the cadmium concentration by about half, without affecting the growth or yield of the rice plants.
"This technology has succeeded in reducing just the concentration of cadmium in rice plants. In other words, the important point about this technology is: it enables cadmium to be reduced without affecting other elements that are nutrients for people, such as zinc and calcium."
"Using technology for controlling the gene we've specified, we can halve the cadmium content of rice, which accounts for half of Japanese people's cadmium intake. So if this technology becomes practical, I think it may help to enhance the health of people in Japan."
VIDEO Low-Cadmium Rice Through Genetic Modification