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 language | English (US) |
|---|---|
| Pages (from-to) | 181-192 |
| Number of pages | 12 |
| Journal | BioMetals |
| Volume | 25 |
| Issue number | 1 |
| DOIs | |
| State | Published - Feb 1 2012 |
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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 journal › Article
}
TY - JOUR
T1 - Siderophore-mediated iron uptake in two clades of Marinobacter spp. associated with phytoplankton
T2 - The role of light
AU - Amin, Shady
AU - Green, David H.
AU - Gärdes, Astrid
AU - Romano, Ariel
AU - Trimble, Lyndsay
AU - Carrano, Carl J.
PY - 2012/2/1
Y1 - 2012/2/1
N2 - 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.
AB - 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.
KW - Gene expression
KW - Iron
KW - Light
KW - Marinobacter
KW - Siderophores
KW - Transport
UR - http://www.scopus.com/inward/record.url?scp=84861216360&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84861216360&partnerID=8YFLogxK
U2 - 10.1007/s10534-011-9495-5
DO - 10.1007/s10534-011-9495-5
M3 - Article
C2 - 21947474
AN - SCOPUS:84861216360
VL - 25
SP - 181
EP - 192
JO - BioMetals
JF - BioMetals
SN - 0966-0844
IS - 1
ER -