Development of a genetic tool for activating chromosomal expression of cryptic or tightly regulated loci in Pseudomonas aeruginosa

A method for replacing endogenous promoter by a constitutive promoter in Pseudomonas aeruginosa is described. Plasmid pKNG101, a broadly used shuttle suicide vector in P. aeruginosa, was improved to allow chromosomal introduction of a Plac promoter in front of any kind of gene especially those with unknown function. Using this strategy alleviates the need for cloning difficulties encountered in this bacteria and antibiotic marker selection.