Construction and validation of a neutrally-marked strain of Pseudomonas fluorescens SBW25

J Microbiol Methods. 2007 Oct;71(1):78-81. doi: 10.1016/j.mimet.2007.07.001. Epub 2007 Jul 10.


Neutrally marked bacterial strains are useful in many experimental evolution and molecular ecology studies to assess the relative fitness of a given strain. Here we describe the construction and validation of a neutral marker for the model organism Pseudomonas fluorescens SBW25. The marked strain, called SBW25-lacZ, was created by integrating a promoterless 'lacZ into the defective prophage locus of the SBW25 chromosome. Fitness assays conducted in various laboratory media and in planta revealed that the fitness levels of SBW25-lacZ were comparable with the wild-type ancestor.

MeSH terms

  • Biomarkers*
  • Chromosomes, Bacterial / genetics
  • Genetic Engineering
  • Lac Operon / physiology
  • Pseudomonas fluorescens / genetics*
  • Pseudomonas fluorescens / growth & development
  • Pseudomonas fluorescens / physiology*
  • Selection, Genetic


  • Biomarkers