Arsenic is an extremely toxic metalloid pollutant yet the decontamination of polluted sites can be environmentally destructive. An alternative is suggested in October 7 Nature Biotechnology; Om Parkash Dhankher and colleagues at the University of Georgia, Athens, US, show that genetically engineered plants can transport arsenic above ground, reduce it to arsenite, and sequester it in thiol–peptide complexes (Nature Biotechnology, DOI:10.1038/nbt747, October 7, 2002).

Dhankher et al. examined the effects of coexpressing two bacterial genes, arsenate reductase (arsC)

and γ-glutamylcysteine synthetase (γ-ECS), in Arabidopsis plants. They observed that plants expressing SRS1p/ArsC and ACT2p/ γ-ECS together showed substantially greater arsenic tolerance than wild-type plants or plants expressing γ-ECS alone. In addition, when grown on arsenic, these plants accumulated 4–17-fold greater fresh shoot weight and accumulated 2– 3-fold more arsenic per gram of tissue than wild-type plants or plants expressing γ-ECS or ArsC alone.

"These transgenic technologies and the understanding of the physiology of arsenic behavior in plants should lead to the development of high-biomass, fast-growing arsenic hyperaccumulator plants for field use," conclude the authors.