Researchers from FIU’s Herbert Wertheim College of Medicine are part of an international team that has identified how arsenic builds up in the seeds of plants similar to rice. The discovery holds the promise of the future development of healthier rice grains.
“While the process of how arsenic is taken into roots and shoots of plants is fairly well understood, little is known about how arsenic gets into seeds,” says Distinguished Professor Barry P. Rosen, Ph.D. “Understanding how arsenic is accumulated in seeds such as the rice grain is of critical importance in population health.”
Rosen and colleague Jian Chen, Ph.D., both from the Department of Cellular Biology and Pharmacology are among the team of scientists who discovered how arsenic accumulates in the seeds of the plant Arabidopsis thaliana, which is used as a model for food plants such as rice.
Arsenic is both a toxin and a carcinogen that comes from minerals and is used in some herbicides, animal growth promoters, and semiconductors. It is a pervasive environmental contaminant of food and water that threatens the health of tens of millions people worldwide. Rice is the staple food for more than half of the people in the world. Even here in the U.S. where we are not large consumers, the average American eats 25 pounds of rice per year, according to the U.S. Rice Producers Association.
The U.S. Environmental Protection Agency (EPA) ranks arsenic first on the U.S. Priority List of Hazardous Substances (http://www.atsdr.cdc.gov/SPL/index.html). The EPA asserts that it pervades our drinking water, and the U.S. Food and Drug Administration is concerned about arsenic endangering the safety of our food supply.
The major source of dietary arsenic is from eating plants such as rice that have accumulated arsenic. And rice is a major component of the diet of more than 2.5 billion people worldwide. In China, for example, about 60 percent of daily dietary arsenic comes from rice consumption.
As reported in an upcoming article in the prestigious journal Nature Plants, Rosen’s team discovered that the plant, A. thaliana, uses transport systems for inositol, a type of sugar, to load arsenite, the toxic form of arsenic, into seeds. This is the first identification of transporters responsible for arsenic accumulation in seeds.
Rosen predicts that the same pathway is how arsenic accumulates in the rice grain and that discoveries such as these will enable the development of new rice cultivators with less arsenic in the grain, a major advance toward minimizing the global health risks posed by arsenic in rice and possibly, in the near future, in other food sources.