Identification of genes involved in swarming motility using a Pseudomonas aeruginosa PAO1 mini-Tn5-lux mutant library

During a screening off a mini-Tn5-luxCDABE transposon mutant library of Pseudomonas aeruginosa PAO1 for alterations in swarming motility, 36 mutants were identified with Tn5 insertions in genes for the synthesis or function of flagellin and type IV pilus, in genes for the Xcp-related type II secretion system, and in regulatory, metabolic, chemosensory, and hypothetical genes with unltnown functions. These mutants were differentially affected in swimming and twitching motility but in most cases had only a minor additional motility defect. Our data provide evidence that swarming is a more complex type of motility, since it is influenced by a large number of different genes in P. aeruginosa. Conversely, many of the swarming-negative matants also showed, an impairment in biofilm formation, indicating a strong relationship between these types of growth states.