Mini‐Tn 7 transposons for site‐specific tagging of bacteria with fluorescent proteins

Summary The mini‐Tn 7 transposon system is a convenient tool for site‐specific tagging of bacteria in which the tagging DNA is inserted at a unique and neutral chromosomal site. We have expanded the panel of mini‐Tn 7 delivery plasmids expressing different fluorescent proteins (stable and unstable) from the Escherichia coli lac derived promoter, P A1/04/03 , or from the growth‐rate‐dependent Escherichia coli promoter P rrnB P1 . The mini‐Tn 7 transposons were inserted and tested in the soil bacterium, Pseudomonas putida KT2440. Successful and site‐specific tagging was verified by Southern blots as well as by PCR. Furthermore, the effect of fluorescent protein expression on the cellular growth rate was tested by growth competition assays.