Phytodetoxification of the environmental pollutant and explosive 2,4,6-trinitrotoluene

Our recent study highlights the role of 2 glutathione transferases (GSTs) in thedetoxification of the environmental pollutant, 2,4,6-trinitrotoluene (TNT) inArabidopsis thaliana. TNT is toxic and highly resistant tobiodegradation in the environment, raising both health and environmental concerns. TwoGSTs, GST-U24 and GST-U25, are upregulated in response to TNT treatment, and expressedpredominantly in the root tissues; the site of TNT location following uptake. Plantsoverexpressing GST-U24 and GST-U25 exhibited significantly enhanced ability to withstandand detoxify TNT, and remove TNT from contaminated soil. Analysis of the catalyticactivities of these 2 enzymes revealed that they form 3 TNT-glutathionyl products. Ofparticular interest is 2-glutathionyl-4,6-dinitrotoluene as this represents a potentiallyfavorable step toward subsequent degradation and mineralization of TNT. We demonstrate howGSTs fit into what is already known about pathways for TNT detoxification, and discuss theshort and longer-term fate of TNT conjugates in planta.