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A TonB-dependent outer membrane receptor of Pseudomonas fluorescens: virulence and vaccine potential

Yong-hua Hu1, Wei Dang, Li Sun

  • 1Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, People's Republic of China.

Archives of Microbiology
|April 25, 2012
PubMed

Insights

Researchers identified TdrA, a protein from the aquaculture pathogen Pseudomonas fluorescens, as crucial for iron uptake and bacterial virulence. Vaccinating with TdrA provided significant protection against infection in fish.

Area of Science:

  • Microbiology
  • Immunology
  • Aquaculture Science

Background:

  • Pseudomonas fluorescens is a significant Gram-negative bacterial pathogen in aquaculture.
  • TonB-dependent outer membrane receptors play vital roles in bacterial nutrient acquisition and virulence.

Purpose of the Study:

  • To identify and characterize a TonB-dependent outer membrane receptor, TdrA, from a pathogenic P. fluorescens strain.
  • To investigate the function of TdrA in bacterial iron acquisition and virulence.
  • To evaluate the vaccine potential of TdrA against P. fluorescens infection in fish.

Main Methods:

  • Identification and structural analysis of TdrA.
  • Quantitative real-time reverse transcriptase-PCR to assess tdrA gene expression.
  • Construction and characterization of a tdrA-knockout mutant.
  • Production and purification of recombinant TdrA (rTdrA).
  • Vaccination of flounder with rTdrA and subsequent challenge experiments.

Main Results:

  • TdrA is a TonB-dependent outer membrane receptor upregulated under iron starvation and during host cell infection.
  • A tdrA-knockout mutant showed impaired growth in iron-deficient conditions, reduced virulence, and inability to establish lethal infections.
  • Immunization with rTdrA induced protective immunity and antibody production in flounder, conferring protection against lethal P. fluorescens challenge.

Conclusions:

  • TdrA is essential for Pseudomonas fluorescens virulence, likely through its role in iron acquisition.
  • TdrA is a promising subunit vaccine candidate for protecting aquaculture species against P. fluorescens infections.

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