Rapid and highly efficient method for scarless mutagenesis within the Salmonella enterica chromosome

Direct manipulation of bacterial chromosomes by recombination-based techniques has become increasingly important for both cognitive and applied research. Here we demonstrate, for the first time, the combination of the Red recombinase system with I-SceI endonuclease-based selection of successful recombinants after electroporation with short synthetic oligonucleotides. We show the generation of scarless gene knockouts as well as site-directed mutagenesis using the Salmonella virulence-associated two component signaling system PhoPQ. The presented approach is very versatile for generating in-frame deletions, point mutations or insertions within bacterial chromosomes.