June 10, 2008

Researchers Find Link To Arsenic Absorption In Crops

Scandinavian scientists believe they may have discovered a gene that could prevent people from eating levels of the poisonous metal arsenic, which can be absorbed by crops like rice.

Apparently a gene, called nodulin26-like intrinsic protein, is responsible for protecting crops by allowing them to absorb silicon in cell walls as a defense against fungal infections.

"Our observations ... may provide a key to the development of low arsenic crops for food production," wrote the team from the University of Copenhagen in Denmark and the University of Gothenburg in Sweden.

Arsenic is a naturally occurring element in crops that can build up over time in animals or plants, causing them to develop lung disease and cancers, even long after exposure.

The primary source of arsenic is contaminated water, followed by foods like rice, which are irrigated with contaminated water.

Tens of millions of people in dozens of countries in the developing and developed world drink unsafe water containing arsenic levels above World Health Organization guidelines, according to research presented last year at the Royal Geographical Meeting in London.

Arsenic is acutely toxic to all organisms and is rated as a group I human carcinogen by the International Agency for Research of Cancer

The researchers found that when yeast was injected into the plants without the nodulin26-like intrinsic protein, the plants accumulated arsenite, one of the most common forms of arsenic.

"This is the genetic proof," Jahn said in a telephone interview.

The findings could one day lead to genetically engineered crops that allow rice, for example, to accumulate silicon but not arsenic, Jahn said.

"The plant is not able to discriminate between these very similar compounds -- one of which is extremely toxic and the other which is extremely important for life," he said.

The study is published in the journal BioMed Central Biology.


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University of Copenhagen

University of Gothenburg