Field trial demonstrating phytoremediation of the military explosive RDX by XplA/XplB-expressing switchgrass

The explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a major component of munitions, is used extensively on military training ranges. As a result, widespread RDX pollution in groundwater and aquifers in the United States is now well documented. RDX is toxic, but its removal from training ranges is logistically challenging, lacking cost-effective and sustainable solutions. Previously, we have shown that thale cress (Arabidopsis thaliana) engineered to express two genes, xplA and xplB, encoding RDX-degrading enzymes from the soil bacterium Rhodococcus rhodochrous 11Y can break down this xenobiotic in laboratory studies. Here, we report the results of a 3-year field trial of XplA/XplB-expressing switchgrass (Panicum virgatum) conducted on three locations in a military site. Our data suggest that XplA/XplB switchgrass has in situ efficacy, with potential utility for detoxifying RDX on live-fire training ranges, munitions dumps and minefields. Switchgrass engineered to express two enzymes that degrade the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) detoxifies military sites contaminated with the munition when grown on these plots in a 3-year field trial.

Automated summary

A 3-year field trial has shown that switchgrass engineered to express XplA/XplB enzymes can effectively detoxify military sites contaminated with RDX, providing a potential solution for cleaning up live-fire training ranges, munitions dumps, and minefields.