Mutant plants may help fight toxic TNT pollution: study

Scientists have identified a mutation in plants that allows them to break down TNT, raising the possibility of a new approach to cleaning up land contaminated by the commonly used explosive.

TNT, or 2,4,6-trinitrotoluene, has become highly prevalent in soil in the last century, particularly at manufacturing waste sites, mines, and military conflict zones. TNT is a toxic and persistent environmental pollutant, and in plants, it accumulates in the roots, inhibiting growth and development.

Using a class of plant called Arabidopsis thaliana, researchers at Britain's University of York found that a key plant enzyme -- MDHAR6 -- reacts with TNT, generating reactive superoxide, which is highly damaging to cells.

However, a mutation in a gene that controls MDHAR6 allows these plants to have long roots and bushy leaves when grown in TNT-treated soil.

An analysis by the researchers revealed that there was no decrease in TNT concentration in the roots in the presence of the mutation. However, measuring electron activity revealed a one-electron reduction of TNT, an alteration that rendered the explosive less toxic to the plant.

By targeting this enzyme in relevant plant species, it may be possible to produce TNT resistant plants to revegetate and remediate explosives at contaminated sites such as military ranges and manufacturing waste sites, they said.

"Only by eliminating the acute phytotoxicity of TNT can plant-based systems be successfully used to clean-up contaminated sites," study author Liz Rylott of the university said. "Our work is an important step on that journey."

The findings were published in the U.S. journal Science Thursday. Endit