Expression of a Drosophila glutathione transferase in Arabidopsis confers the ability to detoxify the environmental pollutant, and explosive, 2,4,6‐trinitrotoluene

Summary The explosive 2,4,6‐trinitrotoluene (TNT) is a significant, global environmental pollutant that is both toxic and recalcitrant to degradation. Given the sheer scale and inaccessible nature of contaminated areas, phytoremediation may be a viable clean‐up approach. Here, we have characterized a Drosophila melanogaster glutathione transferase (DmGSTE6) which has activity towards TNT. Recombinantly expressed, purified DmGSTE6 produces predominantly 2‐glutathionyl‐4,6‐dinitrotoluene, and has a 2.5‐fold higher Maximal Velocity (Vmax), and five‐fold lower Michaelis Constant (Km) than previously characterized TNT‐active Arabidopsis thaliana (Arabidopsis) GSTs. Expression of DmGSTE6 in Arabidopsis conferred enhanced resistance to TNT, and increased the ability to remove TNT from contaminated soil relative to wild‐type plants. Arabidopsis lines overexpressing TNT‐active GSTs AtGST‐U24 and AtGST‐U25 were compromised in biomass production when grown in the absence of TNT. This yield drag was not observed in the DmGSTE6‐expressing Arabidopsis lines. We hypothesize that increased levels of endogenous TNT‐active GSTs catalyse excessive glutathionylation of endogenous substrates, depleting glutathione pools, an activity that DmGST may lack. In conclusion, DmGSTE6 has activity towards TNT, producing a compound with potential for further biodegradation. Selecting or manipulating plants to confer DmGSTE6‐like activity could contribute towards development of phytoremediation strategies to clean up TNT from polluted military sites.