Nice Rice: Reducing Cadmium in World’s Most Popular Grain

Nice Rice: Reducing Cadmium in World’s Most Popular Grain

I do enjoy a fluffy helping of rice, next to a spicy curry, or as the base for a silky risotto. And so does a healthy chunk of the world’s population! But this perfect carb has a dark side: The grains easily absorb environmental cadmium, a heavy metal that can accumulate in the human body and have a devastating effect on our health. Researchers have recently dived into the grain’s genome to search for a solution. With a bit of strategic genetic manipulation, a team from Okayama University has developed a strain of rice that absorbs less cadmium from contaminated soil and water—allowing for crops to be grown (and enjoyed!) while longer-term cleanup efforts get underway.

“Professor [Jian Feng] Ma and the members of his research team examined 132 accessions of rice and discovered that the gene OsNramp5, when duplicated in tandem, decreased the accumulation of cadmium in Pokkali, a type of rice cultivated for three thousand years in Kerala, India. OsNramp5 encodes a cadmium and manganese transporter protein in rice, according to earlier research. When the same gene is duplicated in tandem, it increases the absorption of both minerals into root cells. As a result, manganese and cadmium compete in the cells for translocation to the shoots, which in turn inhibits cadmium from building up in these regions. […]

As Pokkali stores extremely low cadmium in its shoots, the scientists introgressed (a term for the transfer of genetic information across species) the duplicated OsNramp5 gene in Koshihikari, a variety of rice that is very popular in Japan but accumulates relatively high levels of cadmium. Explaining how targeted breeding can help humans, Professor Ma says, ‘We identified a gene responsible for differential accumulation of cadmium in rice grain based on natural variations in cadmium accumulation. Then, we applied this gene to successfully breed rice cultivars with low cadmium accumulation in the grain.’”

Professor Ma makes it seem so easy—a simple solution for a simple grain. But the complex science shows how interconnected these varieties of rice are, both with each other and the Earth. I hope this creation buys us some time to get our cadmium-dumping act together. I’m glad we won’t have to starve while doing so!