Transposon mutations in the flagella biosynthetic pathway of the solvent-tolerant Pseudomonas putida S12 result in a decreased expression of solvent efflux genes

Fourteen solvent-sensitive transposon mutants were generated from the solve nt-tolerant Pseudomonas putida strain S12 by applying the TnMOD-KmO mutagen esis system. These mutants were unable to grow in the presence of octanol a nd toluene. By cloning the region flanking the transposon insertion point a partial sequence of the interrupted genes was determined. Comparison of th e deduced amino acid sequences with a protein database revealed the followi ng interrupted putative gene products: organic solvent efflux proteins SrpA and SrpB. the flagellar structural proteins FlgK, FlaG, Flif. FliC. and Fl iH, the transcriptional activator FleQ, the alternative RNA polymerase sigm a Factor RpoN, and the flagellum-specific RNA polymerase sigma factor FliA (RpoF). The transposon mutants, except for the organic solvent afflux mutan ts, were nonmotile as determined by a swarm assay and the formation of the flagellum was totally impaired. Expression studies with a sri, Promoter pro be showed a decreased expression of the SrpABC efflux pump in the nonmotile mutants. (C) 2001 Federation of European Microbiological Societies. Publis hed by Elsevier Science B.V. Ail rights reserved.