Identification and functional characterization of pfm, a novel gene involved in swimming motility of Pseudomonas aeruginosa

Pseudomonas aeruginosa, an important opportunistic pathogen, has a single polar flagellum which is an important virulence and colonization factor by providing swimming motility. This paper describes the functional characterization of a novel gene pfm (PA2950) of P. aeruginosa. The pfm encodes a protein that is similar to a number of short-chain alcohol dehydrogenases of other bacterial species. Mutation of this gene results in a defect in swimming motility which can be completed back to that of wild type by a plasmid containing the pfm. Interestingly, the pfm mutant possesses an intact flagellum which does not rotate, thus giving rise to a non-motile phenotype. The pfm gene is encoded on an operon together with two upstream genes which code for electron transfer flavoprotein (ETF). Yeast two-hybrid tests indicated that the PFM interacts with the ETF, suggesting that the putative dehydrogenase (PFM) is involved in energy metabolism that is critical for the rotation of flagellum in P. aeruginosa.