Monodehydroascorbate reductase mediates TNT toxicity in plants

Science. 2015 Sep 4;349(6252):1072-5. doi: 10.1126/science.aab3472.

Abstract

The explosive 2,4,6-trinitrotoluene (TNT) is a highly toxic and persistent environmental pollutant. Due to the scale of affected areas, one of the most cost-effective and environmentally friendly means of removing explosives pollution could be the use of plants. However, mechanisms of TNT phytotoxicity have been elusive. Here, we reveal 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), with Arabidopsis deficient in MDHAR6 displaying enhanced TNT tolerance. This discovery will contribute toward the remediation of contaminated sites. Moreover, in an environment of increasing herbicide resistance, with a shortage in new herbicide classes, our findings reveal MDHAR6 as a valuable plant-specific target.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Air Pollutants / chemistry
  • Air Pollutants / metabolism
  • Air Pollutants / toxicity*
  • Arabidopsis / drug effects*
  • Arabidopsis / enzymology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Environmental Restoration and Remediation*
  • Explosive Agents / metabolism
  • Explosive Agents / toxicity*
  • Frameshift Mutation
  • Herbicide Resistance / genetics
  • Herbicides / chemistry
  • Herbicides / metabolism
  • Herbicides / pharmacology
  • Mitochondria / enzymology
  • NADH, NADPH Oxidoreductases / genetics
  • NADH, NADPH Oxidoreductases / metabolism*
  • Plastids / enzymology
  • Stress, Physiological / genetics
  • Stress, Physiological / physiology
  • Superoxides / metabolism
  • Trinitrotoluene / chemistry
  • Trinitrotoluene / metabolism
  • Trinitrotoluene / toxicity*

Substances

  • Air Pollutants
  • Arabidopsis Proteins
  • Explosive Agents
  • Herbicides
  • Superoxides
  • Trinitrotoluene
  • MDHAR6 protein, Arabidopsis
  • NADH, NADPH Oxidoreductases