Identification of an iron acquisition machinery in Flavobacterium columnare

Lingyu Guan, Javier Santander, Melha Mellata, Yuangxing Zhang, Roy Curtiss

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Flavobacterium columnare, a fastidious Gram-negative pathogen and the causative agent of columnaris disease, is one of the most harmful pathogens in the freshwater fish-farming industry. Nevertheless the virulence mechanisms of F. columnare are not well understood. Bacterial iron uptake from the host during infection is an important mechanism of virulence. Here we identified and analyzed part of the iron uptake machinery of F. columnare. Under iron-limited conditions during in vitro growth, synthesis of an outer membrane protein of ~86 kDa was upregulated. This protein was identified as a TonB-dependent ferrichrome-iron receptor precursor (FhuA). Synthesis of siderophores in F. columnare was corroborated by chrome azurol S assays. A putative ferric uptake regulator (Fur) protein was also identified in the F. columnare genome. Structural analysis of the F. columnare Fur protein revealed that it was similar to Fur proteins involved in iron uptake regulation of other bacteria. Furthermore, Salmonella enterica serovar Typhimurium (S. Typhimurium) Δfur mutants were partially complemented by the F. columnare fur gene. We conclude that a siderophore-mediated iron uptake system exists in F. columnare, and fur from F. columnare could partially complement S. Typhimurium Δfur mutant.

Original languageEnglish (US)
Pages (from-to)129-138
Number of pages10
JournalDiseases of Aquatic Organisms
Issue number2
StatePublished - Oct 11 2013


  • FhuA
  • Flavobacterium columnare
  • Fur
  • Iron uptake
  • Siderophore

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science


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