Revealing the Mechanisms Driving Arsenic Accumulation in Plants

Arsenic is a human carcinogen that accumulates from soil into plants including crops. Once inside crops arsenic presents a cancer risk when consumed in foods made from such crops. Because of these food safety concerns research into understanding the mechanisms driving arsenic accumulation in plants has become a priority, and significant advances have been made. Plants can control the amount of arsenic they accumulate in several ways. They can reduce the amount of arsenic they allow into roots by shutting off the pathway arsenic uses to enter. The arsenic that is still able to enter is either transported back out into the soil using an as yet unknown pumping mechanism, or the arsenic is stored in a non-toxic form in a safe location inside root cells. Even with these mechanisms in place some arsenic is still able to enter the plants vascular system and use it to escape the root, allowing arsenic to be transported from the roots into leaves and any developing seeds or grain. To enter the vascular system arsenic hijacks processes that the plant normally uses to transport chemicals that are essential to the plant, including phosphorus, silica and certain types of sugars. This knowledge is now creating new opportunities to limit arsenic accumulation in food crops, thereby helping to reduce the cancer risk from this food-chain contaminant.