Green, D. H., The Scottish Association for M, Oban, United Kingdom, david.green@sams.ac.uk
Hart, M. C., The Scottish Association for Marine Science, Oban, United Kingdom, Mark.Hart@sams.ac.uk
Carrano, C. J., San Diego State University, San Diego, USA, carrano@sciences.sdsu.edu
Kuepper, F. C., The Scottish Association for Marine Science, Oban, United Kingdom, fck@sams.ac.uk
Amin, S. A., San Diego State University, San Diego, USA, shady.a.amin@gmail.com

THE ROLE OF SYMBIOTIC BACTERIAL SIDEROPHORES IN PROMOTING PRIMARY PRODUCTIVITY

The development of primary productivity in the marine environment is critical to the marine food web and the sequestration of anthropogenic CO₂. While phytoplankton fix CO₂ in to biomass, the remineralization and major biogeochemical cycles are driven by bacterioplankton – the microbial mileu that surrounds phytoplankton at various spatial scales. While phytoplankton cells in the field and laboratory culture act as ‘hot-spots’ for bacterial activity because of the exudates they excrete, emerging evidence suggests that some bacterial associates of phytoplankton are important to the growth and physiological well-being of algal cells. However, our understanding of the nature of such inter-kingdom interaction is still in its infancy. One hypothesis for such a phenomenon may be that phytoplankton ‘hijack’ iron, an element that often limits their growth, from extracellular siderophores produced by bacterial associates. Here we report the isolation of a range of Marinobacter species from different phytoplankton cultures, and the chemical isolation and characterization of the extracellular siderophores produced, coupled with genomic analysis of one producing strain. Strains belonging to two species-clusters were found to produce the dicitrate siderophore, Vibrioferrin (VF), and contained genes necessary for its production. Our evidence suggests that VF could have a role in supplying phytoplankton with their limiting nutrient.

Poster presentation

Presentation is given by student: Yes
Session #:120
Date: 03-03-2008
Time: 17:30 - 19:30