Rice tends to absorb arsenic from the soil more readily than other food crops, prompting concern about the presence of the chemical in baby food. “Scientists have identified enzymes that help rice plant roots tame arsenic, converting it into a form that can be pushed back into the soil,” thereby reducing the threat to humans, says Science News.
The key is for the plants to convert arsenate into arsenite; both are forms of arsenic but rice plants are able to expel arsenite. A team led by biologist David Salt of the University of Nottingham, in England, found that when rice plants lack the genes to produce enzymes called HAC1;1 and HAC1;2, they could not perform the conversion. “When the scientists made HAC1;1 and HAC1;2 genes in other rice plants produce more of the enzymes than usual, grains from those plants had lower concentrations of any form of arsenic,” said Science News.
“So to create rice plants that are better at dealing with arsenic, Salt and other scientists are looking not just at how roots push out arsenic once it gets in, but how they keep the toxin out to begin with.” Since arsenate and arsenite are forms of potentially toxic arsenic, both can appear in a field. Arsenite is more common when rice fields are flooded, while arsenate is prevalent when soils are drier.