Iron Utilization in Marine Cyanobacteria and Eukaryotic Algae

Morrissey, Joe; Bowler, Chris

doi:10.3389/fmicb.2012.00043

Cited by 140 publications

(131 citation statements)

References 143 publications

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“…When compared with lactate-grown co-cultures (Supplementary Table S7), Synechococcus 7002 transcription profiles displayed downregulation of photorespiration and carbohydrate metabolism genes during co-culturing with HCO 3 À . These patterns as well as elevated transcript levels of Fe acquisition genes (Table 5) are more likely to be linked to the increased production of light-capturing and photosynthetic machinery (Ludwig and Bryant, 2012;Morrissey and Bowler, 2012) and higher CO 2 availability (Table 1). Similarly, lower mRNA levels of putative nitrile/cyanate, dipeptide and amino acids transporter genes suggested decreased need for additional (organic) carbon sources during photoautotrophic growth of Synechococcus 7002.…”

Section: Identification Of Putative Interactions Through Metabolite Pmentioning

confidence: 99%

Inference of interactions in cyanobacterial–heterotrophic co-cultures via transcriptome sequencing

et al. 2014

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We used deep sequencing technology to identify transcriptional adaptation of the euryhaline unicellular cyanobacterium Synechococcus sp. PCC 7002 and the marine facultative aerobe Shewanella putrefaciens W3-18-1 to growth in a co-culture and infer the effect of carbon flux distributions on photoautotroph-heterotroph interactions. The overall transcriptome response of both organisms to co-cultivation was shaped by their respective physiologies and growth constraints. Carbon limitation resulted in the expansion of metabolic capacities, which was manifested through the transcriptional upregulation of transport and catabolic pathways. Although growth coupling occurred via lactate oxidation or secretion of photosynthetically fixed carbon, there was evidence of specific metabolic interactions between the two organisms. These hypothesized interactions were inferred from the excretion of specific amino acids (for example, alanine and methionine) by the cyanobacterium, which correlated with the downregulation of the corresponding biosynthetic machinery in Shewanella W3-18-1. In addition, the broad and consistent decrease of mRNA levels for many Fe-regulated Synechococcus 7002 genes during co-cultivation may indicate increased Fe availability as well as more facile and energy-efficient mechanisms for Fe acquisition by the cyanobacterium. Furthermore, evidence pointed at potentially novel interactions between oxygenic photoautotrophs and heterotrophs related to the oxidative stress response as transcriptional patterns suggested that Synechococcus 7002 rather than Shewanella W3-18-1 provided scavenging functions for reactive oxygen species under co-culture conditions. This study provides an initial insight into the complexity of photoautotrophic-heterotrophic interactions and brings new perspectives of their role in the robustness and stability of the association.

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Section: Identification Of Putative Interactions Through Metabolite Pmentioning

confidence: 99%

Inference of interactions in cyanobacterial–heterotrophic co-cultures via transcriptome sequencing

et al. 2014

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“…The composition of Fe transporters analyzed here is not unique. Many microorganisms possess the genetic potential for multiple iron transporters (Rivers et al, 2009;Desai et al, 2012;Hopkinson and Barbeau, 2012;Morrissey and Bowler, 2012). Bioinformatic analyses of iron transport genes revealed that fut genes are common in cyanobacteria (Rivers et al, 2009;Hopkinson and Barbeau, 2012, with additional analysis included in Supplementary Figure S4).…”

Section: Coordinated Transporter Activity C Kranzler Et Almentioning

confidence: 99%

“…This pathway is well-characterized in eukaryotic phytoplankton (Jones et al, 1987;Soria-Dengg and Horstmann, 1995;Maldonado and Price, 2001;Shaked et al, 2005;Allen et al, 2007;Morrissey and Bowler, 2012) and involves plasma membrane reductases that promote the reductive dissociation of organically bound Fe(III). In contrast to substrate-specific siderophore-mediated iron uptake, this strategy grants phytoplankton access to a wide range of organic and inorganic Fe(III) complexes.…”

Section: Introductionmentioning

confidence: 99%

Coordinated transporter activity shapes high-affinity iron acquisition in cyanobacteria

et al. 2013

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Iron bioavailability limits biological activity in many aquatic and terrestrial environments. Broad scale genomic meta-analyses indicated that within a single organism, multiple iron transporters may contribute to iron acquisition. Here, we present a functional characterization of a cyanobacterial iron transport pathway that utilizes concerted transporter activities. Cyanobacteria are significant contributors to global primary productivity with high iron demands. Certain cyanobacterial species employ a siderophore-mediated uptake strategy; however, many strains possess neither siderophore biosynthesis nor siderophore transport genes. The unicellular, planktonic, freshwater cyanobacterium, Synechocystis sp. PCC 6803, employs an alternative to siderophore-based uptake-reduction of Fe(III) species before transport through the plasma membrane. In this study, we combine short-term radioactive iron uptake and reduction assays with a range of disruption mutants to generate a working model for iron reduction and uptake in Synechocystis sp. PCC 6803. We found that the Fe(II) transporter, FeoB, is the major iron transporter in this organism. In addition, we uncovered a link between a respiratory terminal oxidase (Alternate Respiratory Terminal Oxidase) and iron reduction -suggesting a coupling between these two electron transfer reactions. Furthermore, quantitative RNA transcript analysis identified a function for subunits of the Fe(III) transporter, FutABC, in modulating reductive iron uptake. Collectively, our results provide a molecular basis for a tightly coordinated, high-affinity iron transport system.

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“…For instance, they undergo major architectural changes in photosynthetic membranes involving the over-expression of photosynthetic pigments (Ryan-Keogh et al, 2012), the use Fe-economic pathways for ATP synthesis (Bailey et al, 2008), and the reduction of their Fe requirements (Behrenfeld and Milligan, 2013). In addition, some cyanobacteria have also developed specific high-affinity Fe uptake strategies (Morrissey and Bowler, 2012;Kranzler et al, 2014) such as production of siderophores that enhance Fe bioavailability in their immediate environment (Sunda, 2012). Thus, these complex biological interactions with Fe chemistry challenge the quantification of Fe bioavailability in marine environments.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Acclimation to Iron Limitation Reveals New Insights in Metabolism Regulation of Synechococcus sp. PCC7002

2017

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In large areas of the ocean phytoplankton growth is limited by the scarcity of iron (Fe), an essential co-factor for multiple enzymes. Phytoplankton has hence developed strategies to survive under Fe limitation. Here, we characterize the response to Fe limitation of the cyanobacterium Synechococcus sp. PCC7002 acclimated to different Fe concentrations in chemically characterized synthetic seawater. The inorganic Fe concentrations used represent levels of Fe limitation relevant for different domains of the contemporary ocean. Combining physiological and transcriptomic approaches, we provide evidence of the progression of the physiological responses to increasing levels of Fe limitation. Our results showed a rising number of significantly regulated genes and the complexity of the response to increasing Fe limitation. Mild Fe limitation induced up-regulation of genes involved in Fe uptake, while genes involved in photosynthesis and respiration were down-regulated. Strong Fe limitation induced up-regulation of genes involved in energy metabolism and concomitant down-regulation of macronutrients uptake. Severe Fe limitation affected fine metabolic regulation of co-factors expression and activation of anti-oxidative stress responses. Our results suggest that homeostasis under long-term Fe limitation put at play dramatically different mechanisms for oxidative stress mitigation and carbon metabolism than those previously reported under Fe stress. Hence, evidence the importance of acclimation processes on the performance of cyanobacteria under Fe limitation conditions.

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Iron Utilization in Marine Cyanobacteria and Eukaryotic Algae

Cited by 140 publications

References 143 publications

Inference of interactions in cyanobacterial–heterotrophic co-cultures via transcriptome sequencing

Inference of interactions in cyanobacterial–heterotrophic co-cultures via transcriptome sequencing

Coordinated transporter activity shapes high-affinity iron acquisition in cyanobacteria

Long-Term Acclimation to Iron Limitation Reveals New Insights in Metabolism Regulation of Synechococcus sp. PCC7002

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