title: Expression of a Drosophila glutathione transferase in Arabidopsis confers the ability to detoxify the environmental pollutant, and explosive, 2,4,6-trinitrotoluene.
abstract: 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.
authors.affiliation: Centre for Novel Agricultural Products, Department of Biology, University of York, York, YO10 5DD, UK.
authors.forename: Kyriakos
authors.initials: K
authors.lastname: Tzafestas
authors.affiliation: Centre for Novel Agricultural Products, Department of Biology, University of York, York, YO10 5DD, UK.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Razalan
authors.affiliation: Centre for Novel Agricultural Products, Department of Biology, University of York, York, YO10 5DD, UK.
authors.forename: Ivan
authors.initials: I
authors.lastname: Gyulev
authors.affiliation: Department of Neurochemistry, Stockholm University, S-106 91, Stockholm, Sweden.
authors.forename: Aslam M A
authors.initials: AM
authors.lastname: Mazari
authors.affiliation: Department of Neurochemistry, Stockholm University, S-106 91, Stockholm, Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Mannervik
authors.affiliation: Centre for Novel Agricultural Products, Department of Biology, University of York, York, YO10 5DD, UK.
authors.forename: Elizabeth L
authors.identifier: http://orcid.org/0000-0002-1609-414X
authors.initials: EL
authors.lastname: Rylott
authors.affiliation: Centre for Novel Agricultural Products, Department of Biology, University of York, York, YO10 5DD, UK.
authors.forename: Neil C
authors.initials: NC
authors.lastname: Bruce
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000201:enzymology*; D004785:Environmental Pollutants / Q000633:toxicity*; D004787:Environmental Pollution; D053834:Explosive Agents / Q000633:toxicity*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D008658:Inactivation, Metabolic / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D030821:Plants, Genetically Modified; D014303:Trinitrotoluene / Q000737:chemistry / Q000633:toxicity*
chemical_list: D029681:Arabidopsis Proteins; D029721:Drosophila Proteins; D004785:Environmental Pollutants; D053834:Explosive Agents; D014303:Trinitrotoluene; C000609410:GSTE6 protein, Drosophila; D005982:Glutathione Transferase; D005978:Glutathione
keywords: 
  Drosophila melanogaster
  ; 2,4,6-trinitrotoluene; Arabidopsis; conjugation; detoxification; environmental pollutant; glutathione transferase; phytoremediation