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An explosive-degrading cytochrome P450 activity and its targeted application for the phytoremediation of RDX

Abstract

The widespread presence in the environment of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), one of the most widely used military explosives, has raised concern owing to its toxicity and recalcitrance to degradation. To investigate the potential of plants to remove RDX from contaminated soil and water, we engineered Arabidopsis thaliana to express a bacterial gene xplA encoding an RDX-degrading cytochrome P450 (ref. 1). We demonstrate that the P450 domain of XplA is fused to a flavodoxin redox partner and catalyzes the degradation of RDX in the absence of oxygen. Transgenic A. thaliana expressing xplA removed and detoxified RDX from liquid media. As a model system for RDX phytoremediation, A. thaliana expressing xplA was grown in RDX-contaminated soil and found to be resistant to RDX phytotoxicity, producing shoot and root biomasses greater than those of wild-type plants. Our work suggests that expression of xplA in landscape plants may provide a suitable remediation strategy for sites contaminated by this class of explosives.

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Figure 1: Characterization of cytochrome P450 from XplA.
Figure 2: Characterization of xplA-expressing A. thaliana lines.
Figure 3: RDX-contaminated soil studies on wild-type and 35S::XPLA-10 plants.

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Acknowledgements

The authors would like to thank James Chong for his assistance with the anaerobic assays and Steve Nicklin at DSTL for the supply of energetic materials and useful discussions. This work was supported by grants from the Biotechnology and Biological Sciences Research Council, the UK Ministry of Defense and the US Strategic Environmental Research and Development Program.

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Correspondence to Neil C Bruce.

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Supplementary Fig. 1

RDX contaminated soil studies on wild type and xplA-expressing lines (PDF 398 kb)

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Rylott, E., Jackson, R., Edwards, J. et al. An explosive-degrading cytochrome P450 activity and its targeted application for the phytoremediation of RDX. Nat Biotechnol 24, 216–219 (2006). https://doi.org/10.1038/nbt1184

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