Functional role of PilA in iron acquisition in the cyanobacterium Synechocystis sp. PCC 6803

PLoS One. 2014 Aug 26;9(8):e105761. doi: 10.1371/journal.pone.0105761. eCollection 2014.

Abstract

Cyanobacteria require large quantities of iron to maintain their photosynthetic machinery; however, in most environments iron is present in the form of insoluble iron oxides. Whether cyanobacteria can utilize these sources of iron, and the potential molecular mechanisms involved remains to be defined. There is increasing evidence that pili can facilitate electron donation to extracellular electron acceptors, like iron oxides in non-photosynthetic bacteria. In these organisms, the donation of electrons to iron oxides is thought to be crucial for maintaining respiration in the absence of oxygen. Our study investigates if PilA1 (major pilin protein) may also provide a mechanism to convert insoluble ferric iron into soluble ferrous iron. Growth experiments supported by spectroscopic data of a strain deficient in pilA1 indicate that the presence of the pilA1 gene enhances the ability to grow on iron oxides. These observations suggest a novel function of PilA1 in cyanobacterial iron acquisition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriochlorophylls / metabolism
  • Biological Transport
  • Carotenoids / metabolism
  • Fimbriae Proteins / physiology*
  • Fimbriae, Bacterial / metabolism*
  • Iron / metabolism*
  • Synechocystis / growth & development
  • Synechocystis / metabolism*

Substances

  • Bacteriochlorophylls
  • Fimbriae Proteins
  • Carotenoids
  • Iron

Grants and funding

This study was supported by a Postdoctoral Fellowship to MHM from the New Zealand Foundation for Research and Technology, succeeded by the Ministry of Business, Innovation and Employment; (http://www.msi.govt.nz/). Additional funding was provided through the PhD position awarded to JL by the Norwegian University of Science and Technology, Trondheim, Norway. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.