No need to lock up your daughter, your wife, your backdoor, or run for your life, as AC/DC recommends in their song, T.N.T. Scientists have developed a mutant plant that sucks up TNT in its roots in a tolerable fashion. The mutant, Arabidopsis, could contribute toward the biological remediation of sites that have been contaminated by TNT, according to the paper ‘Monodehydroascorbate reductase mediates TNT toxicity in plants,’ recently published in Science.
WHAT IS TNT?
The explosive 2,4,6-trinitrotoluene (TNT) is best known as a useful explosive material with convenient handling properties. The standard measure of strength of bombs and other explosives is in the explosive yield of TNT. The risk of accidental detonation is low with TNT because of its insensitivity to shock and friction. In order to initiate an explosion, TNT must first be detonated using a pressure wave from a more sensitive explosive called an explosive booster. However, it is poisonous to humans and can be found in high concentrations on soil surfaces. The United States Environmental Protection Agency (USEPA) has declared TNT a pollutant in the last decade, and prioritized its removal.
HOW THIS MUTANT PLANT CAN HELP TNT POLLUTION
The study, published in Science journal, reveals that “phytotoxicity is caused by reduction of TNT in the mitochondria, forming a nitro radical that reacts with atmospheric oxygen, generating reactive superoxide.” The reaction is catalyzed by monodehydroascorbate reductase 6 (MDHAR6). The mutant plant, Arabidopsis, lacks the catalyst MDHAR6 and instead displays enhanced TNT tolerance. This allows the plant to remove TNT from the soil with little to no damage to the plant itself. Professor Neil Bruce, who led the research, said: “There is a lot of interest in natural mechanisms for the removal of recalcitrant toxic chemicals from the biosphere and because of the scale of explosives pollution, particularly on military training ranges, the remediation of polluted land and water as a result of military activity is a pressing global issue.”
HOW TNT HARMS THE ENVIRONMENT
Explosives like TNT used in mining, military operations and construction have left behind polluted soils. Plants do not thrive on these contaminated soils, affecting the biodiversity of certain environments. Specifically, an enzyme found in plant mitochondria and chloroplasts spins out of control when given the explosive TNT, according to the study. The key enzyme is disabled in this mutant plant, Arabidopsis, allowing the plant to tolerate and accumulate TNT. Researchers report that MDHAR6 mutant plants have long roots and bushy leaves, compared with other plants exposed to TNT. Dr. Liz Rylott, who co-led the research, said: “Only by eliminating the acute phytotoxicity of TNT can plant-based systems be successfully used to clean up contaminated sites. Our work is an important step on that journey.”
