Siderophore-mediated iron uptake in two clades of Marinobacter spp. associated with phytoplankton

The role of light

Shady Amin, David H. Green, Astrid Gärdes, Ariel Romano, Lyndsay Trimble, Carl J. Carrano

    Research output: Contribution to journalArticle

    Abstract

    Iron is an essential element for oceanic microbial life but its low bioavailability limits microorganisms in large areas of the oceans. To acquire this metal many marine bacteria produce organic chelates that bind and transport iron (siderophores). We have previously shown that algal-associated heterotrophic bacteria belonging to the c-proteobacterial Marinobacter genus release the siderophore vibrioferrin (VF). The iron-VF complex was shown to be both far more photolabile than all previously examined photolabile siderophores and to generate a photoproduct incapable of re-chelating the released iron. Thus, the photogenerated iron was shown to be highly bioavailable both to the producing bacterium and its algal partner. In exchange, we proposed that algal cells produced dissolved organic matter that helped support bacterial growth and ultimately fueled the biosynthesis of VF through a light-dependent ''carbon for iron mutualism''. While our knowledge of the importance of light to phototrophs is vast, there are almost no studies that examine the effects of light on microbial heterotrophs. Here, we characterize iron uptake mechanisms in ''algal-associated'' VF-producers. Fe uptake by a VF knock-out mutant mimics the wild-type strain and demonstrates the versatility of iron uptake mechanisms in Marinobacter VF-producers. We also show that VF-producers selectively regulate a subset of their siderophore-dependent iron uptake genes in response to light exposure. The regulation of iron uptake and transport genes by light is consistent with the light driven algal-bacterial ''carbon for iron mutualism'' hypothesis in the marine environment.

    Original languageEnglish (US)
    Pages (from-to)181-192
    Number of pages12
    JournalBioMetals
    Volume25
    Issue number1
    DOIs
    StatePublished - Feb 1 2012

    Fingerprint

    Marinobacter
    Phytoplankton
    Siderophores
    siderophores
    Iron
    phytoplankton
    iron
    uptake mechanisms
    Light
    Bacteria
    Symbiosis
    mutualism
    bacteria
    Carbon
    Genes
    heterotrophs
    knockout mutants
    carbon
    Biosynthesis
    chelates

    Keywords

    • Gene expression
    • Iron
    • Light
    • Marinobacter
    • Siderophores
    • Transport

    ASJC Scopus subject areas

    • Biomaterials
    • Biochemistry, Genetics and Molecular Biology(all)
    • Agricultural and Biological Sciences(all)
    • Metals and Alloys

    Cite this

    Siderophore-mediated iron uptake in two clades of Marinobacter spp. associated with phytoplankton : The role of light. / Amin, Shady; Green, David H.; Gärdes, Astrid; Romano, Ariel; Trimble, Lyndsay; Carrano, Carl J.

    In: BioMetals, Vol. 25, No. 1, 01.02.2012, p. 181-192.

    Research output: Contribution to journalArticle

    Amin, Shady ; Green, David H. ; Gärdes, Astrid ; Romano, Ariel ; Trimble, Lyndsay ; Carrano, Carl J. / Siderophore-mediated iron uptake in two clades of Marinobacter spp. associated with phytoplankton : The role of light. In: BioMetals. 2012 ; Vol. 25, No. 1. pp. 181-192.
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