Tracing explosives in soil with transcriptional regulators of Pseudomonas putida evolved for responding to nitrotoluenes

Junkal Garmendia, Aitor de las Heras, Teca Calcagno Galvão, Víctor de Lorenzo

Research output: Contribution to journalArticlepeer-review


Although different biological approaches for detection of anti-personnel mines and other unexploded ordnance (UXO) have been entertained, none of them has been rigorously documented thus far in the scientific literature. The industrial 2,4,6 trinitrotoluene (TNT) habitually employed in the manufacturing of mines is at all times tainted with a small but significant proportion of the more volatile 2,4 dinitrotoluene (2,4 DNT) and other nitroaromatic compounds. By using mutation-prone PCR and DNA sequence shuffling we have evolved in vitro and selected in vivo variants of the effector recognition domain of the toluene-responsive XylR regulator of the soil bacterium Pseudomonas putida that responds to mono-, bi- and trinitro substituted toluenes. Re-introduction of such variants in P. putida settled the transcriptional activity of the cognate promoters (Po and Pu) as a function of the presence of nitrotoluenes in the medium. When strains bearing transcriptional fusions to reporters with an optical output (luxAB, GFP) were spread on soil spotted with nitrotoluenes, the signal triggered by promoter activation allowed localization of the target compounds on the soil surface. Our data provide a proof of concept that non-natural transcription factors evolved to respond to nitroaromatics can be engineered in soil bacteria and inoculated on a target site to pinpoint the presence of explosives. This approach thus opens new ways to tackle this gigantic humanitarian problem.
Original languageEnglish
Pages (from-to)236-46
Number of pages11
JournalMicrobial biotechnology
Issue number3
Publication statusPublished - May 2008


  • Bacterial Proteins
  • Biosensing Techniques
  • DNA-Binding Proteins
  • Explosive Agents
  • Gene Expression Regulation, Bacterial
  • Pseudomonas putida
  • Soil Microbiology
  • Soil Pollutants
  • Transcription Factors
  • Trinitrotoluene
  • Water Pollutants, Chemical


Dive into the research topics of 'Tracing explosives in soil with transcriptional regulators of Pseudomonas putida evolved for responding to nitrotoluenes'. Together they form a unique fingerprint.

Cite this