Pseudomonas aeruginosa motility requires condensing enzyme FabF1

Abstract

Bacterial motility along growth surfaces is classified into swarming, swimming and twitching, and all three modes of translocation are important in virulence. Previous study on genome‐wide screen of motility defective mutant of the opportunistic pathogen Pseudomonas aeruginosa has identified fabF1 as the only gene required for all three types of motility. FabF1 is an elongation condensing enzyme homolog with predicted function in fatty acid biosynthesis. Analysis of the membrane fatty acid composition showed that the fabF1 mutant produced significantly reduced level of cis‐vaccinate comparing to the wild type strain. In addition, the fabF1 mutant exhibited increased sensitivity to antibiotics, indicating an increased permeability to small molecules through the mutant membrane probably due to the altered membrane fatty acid composition. Transmission electron microscopy analysis showed that the fabF1 mutant possessed intact flagella which is required for swarming and swimming motilities, demonstrating the assembly of flagella was not affected by the decreased level of cis‐vaccinate. Supplement of unsaturated fatty acids such as oleate and cis‐vaccinate in the growth medium did not reverse the fabF1 mutant phenotype. In contrast, overexpression of fabF1 on a plasmid restored the cis‐vaccinate level and rescued the motility defect of the fabF1 mutant suggesting a direct relationship between the cis‐vaccinate level with the motility phenotype in P. aeruginosa. (Supported by GM34496)