Testing mini-transposon insertions in P. putida MAD1 and re Regulatory phenotypes brought about by insertions of the mini-Tn 5 Km of pBAM1 in P. putida MAD1. (A) Representation of the reporter module born by the P. putida MAD1 strain. Pu is induced by XylR in the presence of m-xylene vapours. (B) Schematic representation and approximate location of mini-Tn5Km insertions within xylR and lacZ in P. putida MAD1. (C) The reference condition is that of the clones of the non-mutagenized strain exposed to m-xylene and grown on a plate with X-gal for several days, which results in an intense blue colour exacerbated in the centre of the colony. (D) The other pictures represent the variety of the blue/white patterns obtained throughout the P. putida MAD1 mutagenesis experiment. The pictures were obtained with a Leica MZ FLIII stereomicroscope with an Olympus DP70 camera. See Table S3 of Additional File 1 for more details.