Introduction of quorum sensing elements into bacterial bioreporter circuits enhances explosives' detection capabilities.

A possible solution for the standoff detection of buried landmines is based on the use of microbial bioreporters, genetically engineered to emit a remotely detectable optical signal in response to trace amounts of explosives' signature chemicals, mostly 2,4-dinitrotoluene (DNT). Previously developed DNT sensor strains were based on the fusion of a DNT-inducible gene promoter to a reporting element, either a fluorescent protein gene or a bacterial bioluminescence gene cassette. In the present study, a different approach was used: the DNT-inducible promoter activates, in Escherichia coli , the quorum-sensing luxI and luxR genes of Aliivibrio fischeri . N-Acyl homoserine lactone (AHL), synthesized by LuxI, combines with LuxR and activates the bioluminescence reporter genes. The resulting bioreporter displayed a dose-dependent luminescent signal in the presence of DNT. Performance of the sensor strain was further enhanced by manipulation of the sensing element (combining the E. coli DNT-inducible azoR and yqjF gene promoters), by replacing the luminescence gene cassette of Photorhabdus luminescens luxCDABE with A. fischeri luxCDABEG , and by introducing two mutations, eutE and ygdD , into the host strain. DNT detection sensitivity of the final bioreporter was over 340-fold higher than the original construct.
Competing Interests: The authors declare no conflict of interest.
(© 2022 The Authors. Engineering in Life Sciences published by Wiley‐VCH GmbH.)