Scientists Identify Arsenic Transporters in Rice

Arsenic is a highly toxic and potent carcinogen. It is widespread in the Earth’s crust and is taken-up and accumulated by crops. Elevated arsenic accumulation in rice has the potential to become a new disaster for the population in South and Southeast Asia, especially in Bangladesh and India where arsenic-contaminated groundwater is widely used for irrigation. Compared to other cereal crops, paddy rice can accumulate higher levels of the poisonous metal.

Scientists from the Okayama University in Japan and Rothamsted Research in the United Kingdom have identified proteins that facilitate the entry of arsenite, the predominant form of arsenic in paddy soil, into plants cells. The scientists identified two arsenic transporters; the first is responsible for the entry of the metal in roots while the other mediates arsenic buildup in shoots and grains. Enhanced activity of these transporters resulted to increased accumulation of silicon, which benefits yield production but also increases arsenic content in grains. Scientists are looking into the possibility of targeting these transporters to develop rice varieties that accumulate less arsenic.

The article published by PNAS is available at http://www.pnas.org/content/early/2008/07/11/0802361105.full.pdf+html