Biodegradation of explosives by transgenic plants expressing pentaerythritol tetranitrate reductase

Abstract

Plants offer many advantages over bacteria as agents for bioremediation; however, they typically lack the degradative capabilities of specially selected bacterial strains. Transgenic plants expressing microbial degradative enzymes could combine the advantages of both systems. To investigate this possibility in the context of bioremediation of explosive residues, we generated transgenic tobacco plants expressing pentaerythritol tetranitrate reductase, an enzyme derived from an explosive-degrading bacterium that enables degradation of nitrate ester and nitroaromatic explosives. Seeds from transgenic plants were able to germinate and grow in the presence of 1 mM glycerol trinitrate (GTN) or 0.05 mM trinitrotoluene, at concentrations that inhibited germination and growth of wild-type seeds. Transgenic seedlings grown in liquid medium with 1 mM GTN showed more rapid and complete denitration of GTN than wild-type seedlings. This example suggests that transgenic plants expressing microbial degradative genes may provide a generally applicable strategy for bioremediation of organic pollutants in soil.

Eubacterial arylamine N-acetyltransferases – identification and comparison of 18 members of the protein family with conserved active site cysteine, histidine and aspartate residues

“…5b, c). It has been reported that xenobiotic enzymes are often involved in co-metabolism and therefore produced in response to a mixture of substrates or a compound involved earlier in the degradation pathway (French et al, 1999). This may also be the case with the nat operon, implying regulation by aromatic and\or biphenyl-based compounds other than NAT ligands.…”

Impact of Transgenic Tobacco on Trinitrotoluene (TNT) Contaminated Soil Community

“…Two bacterial enzymes were separately expressed in tobacco, pentaerythritol tetranitrate (PETN) reductase (16) and a classical type I nitroreductase (NR) (15), both enzymes deriving from strains of Enterobacter cloacae (17,18) which have been shown to catalyze a two electron reduction of TNT to produce hydroxylamino-and amino-dinitrotoluene derivatives (13). Vila et al recently demonstrated that these TNT metabolites are conjugated to glycose in tobacco as part of the detoxification process (19).…”

Unusual Spectroscopic and Ligand Binding Properties of the Cytochrome P450-Flavodoxin Fusion Enzyme XplA

“…bioremediation using plants or microbes, and published studies have shown the feasibility of the phytoremediation approach for 2,4,6-trinitrotoluene using, for example, tobacco expressing Enterobacter cloacae pentaerythritol tetranitrate reductase (which also degrades the explosive glycerol trinitrate) and Arabidopsis thaliana expressing an Escherichia coli nitroreductase (13,14). In addition, A. thaliana expressing a cytochrome P450 enzyme system (XplA) from Rhodococcus rhodochrous (strain 11Y) was also shown to detoxify RDX (15).…”