Pip, a novel activator of phenazine biosynthesis in Pseudomonas chlororaphis PCL1391

J Bacteriol. 2006 Dec;188(23):8283-93. doi: 10.1128/JB.00893-06. Epub 2006 Sep 22.

Abstract

Secondary metabolites are important factors for interactions between bacteria and other organisms. Pseudomonas chlororaphis PCL1391 produces the antifungal secondary metabolite phenazine-1-carboxamide (PCN) that inhibits growth of Fusarium oxysporum f. sp. radius lycopersici the causative agent of tomato foot and root rot. Our previous work unraveled a cascade of genes regulating the PCN biosynthesis operon, phzABCDEFGH. Via a genetic screen, we identify in this study a novel TetR/AcrR regulator, named Pip (phenazine inducing protein), which is essential for PCN biosynthesis. A combination of a phenotypical characterization of a pip mutant, in trans complementation assays of various mutant strains, and electrophoretic mobility shift assays identified Pip as the fifth DNA-binding protein so far involved in regulation of PCN biosynthesis. In this regulatory pathway, Pip is positioned downstream of PsrA (Pseudomonas sigma factor regulator) and the stationary-phase sigma factor RpoS, while it is upstream of the quorum-sensing system PhzI/PhzR. These findings provide further evidence that the path leading to the expression of secondary metabolism gene clusters in Pseudomonas species is highly complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antifungal Agents / metabolism
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism*
  • Fusarium / drug effects
  • Fusarium / growth & development
  • Genes, Bacterial
  • Genetic Complementation Test
  • Genome, Bacterial*
  • Molecular Sequence Data
  • Phenazines / metabolism*
  • Plant Diseases / microbiology
  • Plant Roots / microbiology
  • Point Mutation
  • Promoter Regions, Genetic
  • Pseudomonas / chemistry*
  • Pseudomonas / genetics
  • Pseudomonas / metabolism*
  • Sequence Alignment
  • Solanum lycopersicum / microbiology
  • Transcription, Genetic
  • Up-Regulation

Substances

  • Antifungal Agents
  • Bacterial Proteins
  • DNA-Binding Proteins
  • Phenazines
  • phenazine-1-carboxamide

Associated data

  • GENBANK/DQ311664