An improved Tn7-lux reporter for broad host range, chromosomally-integrated promoter fusions in Gram-negative bacteria

An improved vector for chromosomally-integrated promoter-lux fusions is described. The modified vector was tested in parallel with the unmodified vector using the well-characterized Escherichia coli araBAD promoter in the Pseudomonas aeruginosa attTn7 site. The modified mini-Tn7 showed reduced background luminescence, and increased luminescence upon induction, giving >16-fold higher induction ratio. •The Tn7 based reporter vector pUC18TminiTn7lux was modified by removal of 467bp of sequence upstream of the luxCDABE bacterial luciferase operon•An EcoRI site within the multiple cloning site (MCS) of pUC18TminiTn7lux was also rendered more useful by a small deletion•The resulting construct, pAG4, was tested by transposition into P. aeruginosa•The results showed a reduced background and greater maximal expression, yielding a >16-fold increase in measured induction