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Srivastava R, Singh N, Kanda T, Yadav S, Yadav S, Atri N. Cyanobacterial Proteomics: Diversity and Dynamics. J Proteome Res 2024; 23:2680-2699. [PMID: 38470568 DOI: 10.1021/acs.jproteome.3c00779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Cyanobacteria (oxygenic photoautrophs) comprise a diverse group holding significance both environmentally and for biotechnological applications. The utilization of proteomic techniques has significantly influenced investigations concerning cyanobacteria. Application of proteomics allows for large-scale analysis of protein expression and function within cyanobacterial systems. The cyanobacterial proteome exhibits tremendous functional, spatial, and temporal diversity regulated by multiple factors that continuously modify protein abundance, post-translational modifications, interactions, localization, and activity to meet the dynamic needs of these tiny blue greens. Modern mass spectrometry-based proteomics techniques enable system-wide examination of proteome complexity through global identification and high-throughput quantification of proteins. These powerful approaches have revolutionized our understanding of proteome dynamics and promise to provide novel insights into integrated cellular behavior at an unprecedented scale. In this Review, we present modern methods and cutting-edge technologies employed for unraveling the spatiotemporal diversity and dynamics of cyanobacterial proteomics with a specific focus on the methods used to analyze post-translational modifications (PTMs) and examples of dynamic changes in the cyanobacterial proteome investigated by proteomic approaches.
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Affiliation(s)
| | - Nidhi Singh
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
| | - Tripti Kanda
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
| | - Sadhana Yadav
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
| | - Shivam Yadav
- Department of Botany, University of Allahabad, Allahabad 211002, India
| | - Neelam Atri
- Department of Botany, M.M.V., Banaras Hindu University, Varanasi 221005, India
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2
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Bolton R, Machelett MM, Stubbs J, Axford D, Caramello N, Catapano L, Malý M, Rodrigues MJ, Cordery C, Tizzard GJ, MacMillan F, Engilberge S, von Stetten D, Tosha T, Sugimoto H, Worrall JAR, Webb JS, Zubkov M, Coles S, Mathieu E, Steiner RA, Murshudov G, Schrader TE, Orville AM, Royant A, Evans G, Hough MA, Owen RL, Tews I. A redox switch allows binding of Fe(II) and Fe(III) ions in the cyanobacterial iron-binding protein FutA from Prochlorococcus. Proc Natl Acad Sci U S A 2024; 121:e2308478121. [PMID: 38489389 PMCID: PMC10962944 DOI: 10.1073/pnas.2308478121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 02/16/2024] [Indexed: 03/17/2024] Open
Abstract
The marine cyanobacterium Prochlorococcus is a main contributor to global photosynthesis, whilst being limited by iron availability. Cyanobacterial genomes generally encode two different types of FutA iron-binding proteins: periplasmic FutA2 ABC transporter subunits bind Fe(III), while cytosolic FutA1 binds Fe(II). Owing to their small size and their economized genome Prochlorococcus ecotypes typically possess a single futA gene. How the encoded FutA protein might bind different Fe oxidation states was previously unknown. Here, we use structural biology techniques at room temperature to probe the dynamic behavior of FutA. Neutron diffraction confirmed four negatively charged tyrosinates, that together with a neutral water molecule coordinate iron in trigonal bipyramidal geometry. Positioning of the positively charged Arg103 side chain in the second coordination shell yields an overall charge-neutral Fe(III) binding state in structures determined by neutron diffraction and serial femtosecond crystallography. Conventional rotation X-ray crystallography using a home source revealed X-ray-induced photoreduction of the iron center with observation of the Fe(II) binding state; here, an additional positioning of the Arg203 side chain in the second coordination shell maintained an overall charge neutral Fe(II) binding site. Dose series using serial synchrotron crystallography and an XFEL X-ray pump-probe approach capture the transition between Fe(III) and Fe(II) states, revealing how Arg203 operates as a switch to accommodate the different iron oxidation states. This switching ability of the Prochlorococcus FutA protein may reflect ecological adaptation by genome streamlining and loss of specialized FutA proteins.
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Affiliation(s)
- Rachel Bolton
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
| | - Moritz M. Machelett
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
- National Oceanography Centre, SouthamptonSO14 3ZH, United Kingdom
| | - Jack Stubbs
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
| | - Danny Axford
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
| | - Nicolas Caramello
- European Synchrotron Radiation Facility, Grenoble Cedex 938043, France
- Hamburg Centre for Ultrafast Imaging, Hamburg Advanced Research Centre for Bioorganic Chemistry, Universität Hamburg, Hamburg22761, Germany
| | - Lucrezia Catapano
- Randall Centre of Cell and Molecular Biophysics, King’s College London, New Hunt’s House, LondonSE1 1UL, United Kingdom
- Medical Research Council Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Martin Malý
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
| | - Matthew J. Rodrigues
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen5232, Switzerland
| | - Charlotte Cordery
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
| | - Graham J. Tizzard
- School of Chemistry, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
| | - Fraser MacMillan
- School of Chemistry, University of East Anglia, NorwichNR4 7TJ, United Kingdom
| | - Sylvain Engilberge
- European Synchrotron Radiation Facility, Grenoble Cedex 938043, France
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, Grenoble Cedex 938044, France
| | - David von Stetten
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg22607, Germany
| | - Takehiko Tosha
- Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center, Sayo, Hyogo679-5148, Japan
| | - Hiroshi Sugimoto
- Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center, Sayo, Hyogo679-5148, Japan
| | | | - Jeremy S. Webb
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
- National Biofilms Innovation Centre (NBIC), University of Southampton, Southampton, SO17 3DF, UK
| | - Mike Zubkov
- National Oceanography Centre, SouthamptonSO14 3ZH, United Kingdom
- Scottish Association for Marine Science, Oban, ScotlandPA37 1QA, United Kingdom
| | - Simon Coles
- School of Chemistry, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
| | - Eric Mathieu
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, Grenoble Cedex 938044, France
| | - Roberto A. Steiner
- Randall Centre of Cell and Molecular Biophysics, King’s College London, New Hunt’s House, LondonSE1 1UL, United Kingdom
- Department of Biomedical Sciences, University of Padova, Padova35131, Italy
| | - Garib Murshudov
- Medical Research Council Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Tobias E. Schrader
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science, Garching85748, Germany
| | - Allen M. Orville
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, DidcotOX11 0FA, United KingdomRosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0QX, United Kingdom
| | - Antoine Royant
- European Synchrotron Radiation Facility, Grenoble Cedex 938043, France
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, Grenoble Cedex 938044, France
| | - Gwyndaf Evans
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
- Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0QX, United Kingdom
| | - Michael A. Hough
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
- School of Life Sciences, University of Essex, ColchesterCO4 3SQ, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, DidcotOX11 0FA, United KingdomRosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0QX, United Kingdom
| | - Robin L. Owen
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, United Kingdom
| | - Ivo Tews
- Biological Sciences, Institute for Life Sciences, University of Southampton, SouthamptonSO17 1BJ, United Kingdom
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3
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Schiksnis C, Xu M, Saito MA, McIlvin M, Moran D, Bian X, John SG, Zheng Q, Yang N, Fu F, Hutchins DA. Proteomics analysis reveals differential acclimation of coastal and oceanic Synechococcus to climate warming and iron limitation. Front Microbiol 2024; 15:1323499. [PMID: 38444803 PMCID: PMC10912551 DOI: 10.3389/fmicb.2024.1323499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/30/2024] [Indexed: 03/07/2024] Open
Abstract
In many oceanic regions, anthropogenic warming will coincide with iron (Fe) limitation. Interactive effects between warming and Fe limitation on phytoplankton physiology and biochemical function are likely, as temperature and Fe availability affect many of the same essential cellular pathways. However, we lack a clear understanding of how globally significant phytoplankton such as the picocyanobacteria Synechococcus will respond to these co-occurring stressors, and what underlying molecular mechanisms will drive this response. Moreover, ecotype-specific adaptations can lead to nuanced differences in responses between strains. In this study, Synechococcus isolates YX04-1 (oceanic) and XM-24 (coastal) from the South China Sea were acclimated to Fe limitation at two temperatures, and their physiological and proteomic responses were compared. Both strains exhibited reduced growth due to warming and Fe limitation. However, coastal XM-24 maintained relatively higher growth rates in response to warming under replete Fe, while its growth was notably more compromised under Fe limitation at both temperatures compared with YX04-1. In response to concurrent heat and Fe stress, oceanic YX04-1 was better able to adjust its photosynthetic proteins and minimize the generation of reactive oxygen species while reducing proteome Fe demand. Its intricate proteomic response likely enabled oceanic YX04-1 to mitigate some of the negative impact of warming on its growth during Fe limitation. Our study highlights how ecologically-shaped adaptations in Synechococcus strains even from proximate oceanic regions can lead to differing physiological and proteomic responses to these climate stressors.
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Affiliation(s)
- Cara Schiksnis
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
| | - Min Xu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, China
| | - Mak A. Saito
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Matthew McIlvin
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Dawn Moran
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Xiaopeng Bian
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
| | - Seth G. John
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
| | - Qiang Zheng
- State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen University, Xiamen, China
| | - Nina Yang
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
- Marine Policy Center, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Feixue Fu
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
| | - David A. Hutchins
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
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4
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Colussi A, Bokhari SNH, Mijovilovich A, Koník P, Küpper H. Acclimation to medium-level non-lethal iron limitation: Adjustment of electron flow around the PSII and metalloprotein expression in Trichodesmium erythraeum IMS101. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149015. [PMID: 37742749 DOI: 10.1016/j.bbabio.2023.149015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/26/2023]
Abstract
The aim of this study was to investigate how acclimation to medium-level, long-term, non-lethal iron limitation changes the electron flux around the Photosystem II of the oceanic diazotroph Trichodesmium erythraeum IMS101. Fe availability of about 5× and 100× lower than a replete level, i.e. conditions common in the natural environment of this cyanobacterium, were applied in chemostats. The response of the cells was studied not only in terms of growth, but also mechanistically, measuring the chlorophyll fluorescence of dark-adapted filaments via imaging fluorescence kinetic microscopy (FKM) with 0.3 ms time resolution. Combining these measurements with those of metal binding to proteins via online coupling of metal-free HPLC (size exclusion chromatography SEC) to sector-field ICP-MS allowed to track the fate of the photosystems, together with other metalloproteins. General increase of fluorescence has been observed, with the consequent decrease in the quantum yields φ of the PSII, while the efficiency ψ of the electron flux between PSII and the PSI remained surprisingly unchanged. This indicates the ability of Trichodesmium to cope with a situation that makes assembling the many iron clusters in Photosystem I a particular challenge, as shown by decreasing ratios of Fe to Mg in these proteins. The negative effect of Fe limitation on PSII may also be due to its fast turnover. A broader view was obtained from metalloproteomics via HPLC-ICP-MS, revealing a differential protein expression pattern under iron limitation with a drastic down-regulation especially of iron-containing proteins and some increase in low MW metal-binding complexes.
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Affiliation(s)
- Antonio Colussi
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic; University of South Bohemia, Faculty of Sciences, Department of Experimental Plant Biology, České Budějovice, Czech Republic
| | - Syed Nadeem Hussain Bokhari
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic
| | - Ana Mijovilovich
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic
| | - Peter Koník
- University of South Bohemia, Faculty of Sciences, Department of Chemistry, České Budějovice, Czech Republic
| | - Hendrik Küpper
- Czech Academy of Sciences, Biology Centre, Institute of Plant Molecular Biology, Laboratory of Plant Biophysics and Biochemistry, České Budějovice, Czech Republic; University of South Bohemia, Faculty of Sciences, Department of Experimental Plant Biology, České Budějovice, Czech Republic.
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5
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Koedooder C, Zhang F, Wang S, Basu S, Haley ST, Tolic N, Nicora CD, Glavina del Rio T, Dyhrman ST, Gledhill M, Boiteau RM, Rubin-Blum M, Shaked Y. Taxonomic distribution of metabolic functions in bacteria associated with Trichodesmium consortia. mSystems 2023; 8:e0074223. [PMID: 37916816 PMCID: PMC10734445 DOI: 10.1128/msystems.00742-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/21/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE Colonies of the cyanobacteria Trichodesmium act as a biological hotspot for the usage and recycling of key resources such as C, N, P, and Fe within an otherwise oligotrophic environment. While Trichodesmium colonies are known to interact and support a unique community of algae and particle-associated microbes, our understanding of the taxa that populate these colonies and the gene functions they encode is still limited. Characterizing the taxa and adaptive strategies that influence consortium physiology and its concomitant biogeochemistry is critical in a future ocean predicted to have increasingly resource-depleted regions.
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Affiliation(s)
- Coco Koedooder
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Israel Oceanographic and Limnological Research, Haifa, Israel
| | - Futing Zhang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Siyuan Wang
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Subhajit Basu
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
- Microsensor Research Group, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Sheean T. Haley
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
| | - Nikola Tolic
- Earth and Biological Sciences, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Carrie D. Nicora
- Earth and Biological Sciences, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Tijana Glavina del Rio
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Sonya T. Dyhrman
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, USA
| | | | - Rene M. Boiteau
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
| | | | - Yeala Shaked
- The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
- The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
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6
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Luo W, Luo YW. Diurnally dynamic iron allocation promotes N 2 fixation in marine dominant diazotroph Trichodesmium. Comput Struct Biotechnol J 2023; 21:3503-3512. [PMID: 37484493 PMCID: PMC10362294 DOI: 10.1016/j.csbj.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/15/2023] [Accepted: 07/04/2023] [Indexed: 07/25/2023] Open
Abstract
Trichodesmium is the dominant photoautotrophic dinitrogen (N2) fixer (diazotroph) in the ocean. Iron is an important factor limiting growth of marine diazotrophs including Trichodesmium mainly because of high iron content of its N2-fixing enzyme, nitrogenase. However, it still lacks a quantitative understanding of how dynamic iron allocation among physiological processes acts to regulate growth and N2 fixation in Trichodesmium. Here, we constructed a model of Trichodesmium trichome in which intracellular iron could be dynamically re-allocated in photosystems and nitrogenase during the daytime. The results demonstrate that the dynamic iron allocation enhances modeled N2 fixation and growth rates of Trichodesmium, especially in iron-limited conditions, albeit having a marginal impact under high iron concentrations. Although the reuse of iron during a day is an apparent cause that dynamic iron allocation can benefit Trichodesmium under iron limitation, our model reveals two important mechanisms. First, the release of iron from photosystems downregulates the intracellular oxygen (O2) production and reduces the demand of respiratory protection, a process that Trichodesmium wastefully respires carbohydrates to create a lower O2 window for N2 fixation. Hence, more carbohydrates can be used in growth. Second, lower allocation of iron to nitrogenase during early daytime, a period when photosynthesis is active and intracellular O2 is high, reduces the amount of iron that is trapped in the inactivated nitrogenase induced by O2. This mechanism further increases the iron use efficiency in Trichodesmium. Overall, our study provides mechanistic and quantitative insight into the diurnal iron allocation that can alleviate iron limitation to Trichodesmium.
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7
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Cerdan-Garcia E, Baylay A, Polyviou D, Woodward EMS, Wrightson L, Mahaffey C, Lohan MC, Moore CM, Bibby TS, Robidart JC. Transcriptional responses of Trichodesmium to natural inverse gradients of Fe and P availability. THE ISME JOURNAL 2022; 16:1055-1064. [PMID: 34819612 PMCID: PMC8941076 DOI: 10.1038/s41396-021-01151-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 12/28/2022]
Abstract
The filamentous diazotrophic cyanobacterium Trichodesmium is responsible for a significant fraction of marine di-nitrogen (N2) fixation. Growth and distribution of Trichodesmium and other diazotrophs in the vast oligotrophic subtropical gyres is influenced by iron (Fe) and phosphorus (P) availability, while reciprocally influencing the biogeochemistry of these nutrients. Here we use observations across natural inverse gradients in Fe and P in the North Atlantic subtropical gyre (NASG) to demonstrate how Trichodesmium acclimates in situ to resource availability. Transcriptomic analysis identified progressive upregulation of known iron-stress biomarker genes with decreasing Fe availability, and progressive upregulation of genes involved in the acquisition of diverse P sources with decreasing P availability, while genes involved in N2 fixation were upregulated at the intersection under moderate Fe and P availability. Enhanced N2 fixation within the Fe and P co-stressed transition region was also associated with a distinct, consistent metabolic profile, including the expression of alternative photosynthetic pathways that potentially facilitate ATP generation required for N2 fixation with reduced net oxygen production. The observed response of Trichodesmium to availability of both Fe and P supports suggestions that these biogeochemically significant organisms employ unique molecular, and thus physiological responses as adaptations to specifically exploit the Fe and P co-limited niche they construct.
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Affiliation(s)
- E Cerdan-Garcia
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK.
| | - A Baylay
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - D Polyviou
- National Oceanography Centre, Southampton, SO14 3ZH, UK
| | | | - L Wrightson
- Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - C Mahaffey
- Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - M C Lohan
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - C M Moore
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - T S Bibby
- Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - J C Robidart
- National Oceanography Centre, Southampton, SO14 3ZH, UK.
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8
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Shafiee RT, Snow JT, Hester S, Zhang Q, Rickaby REM. Proteomic response of the marine ammonia-oxidising archaeon Nitrosopumilus maritimus to iron limitation reveals strategies to compensate for nutrient scarcity. Environ Microbiol 2021; 24:835-849. [PMID: 33876540 DOI: 10.1111/1462-2920.15491] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 03/25/2021] [Indexed: 11/26/2022]
Abstract
Dissolved iron (Fe) is vanishingly low in the oceans, with ecological success conferred to microorganisms that can restructure their biochemistry to maintain high growth rates during Fe scarcity. Chemolithoautotrophic ammonia-oxidising archaea (AOA) are highly abundant in the oceans, constituting ~30% of cells below the photic zone. Here we examine the proteomic response of the AOA isolate Nitrosopumilus maritimus to growth-limiting Fe concentrations. Under Fe limitation, we observed a significant reduction in the intensity of Fe-dense ferredoxins associated with respiratory complex I whilst complex III and IV proteins with more central roles in the electron transport chain remain unchanged. We concomitantly observed an increase in the intensity of Fe-free functional alternatives such as flavodoxin and plastocyanin, thioredoxin and alkyl hydroperoxide which are known to mediate electron transport and reactive oxygen species detoxification, respectively. Under Fe limitation, we found a marked increase in the intensity of the ABC phosphonate transport system (Phn), highlighting an intriguing link between Fe and P cycling in N. maritimus. We hypothesise that an elevated uptake of exogenous phosphonates under Fe limitation may either supplement N. maritimus' endogenous methylphosphonate biosynthesis pathway - which requires Fe - or enhance the production of phosphonate-containing exopolysaccharides known to efficiently bind environmental Fe.
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Affiliation(s)
- Roxana T Shafiee
- Department of Earth Sciences, South Parks Road, University of Oxford, Oxfordshire, OX1 3AN, UK
| | - Joseph T Snow
- Department of Earth Sciences, South Parks Road, University of Oxford, Oxfordshire, OX1 3AN, UK
| | - Svenja Hester
- Department of Biochemistry, South Parks Road, University of Oxford, Oxfordshire, OX1 3QU, UK
| | - Qiong Zhang
- Department of Earth Sciences, South Parks Road, University of Oxford, Oxfordshire, OX1 3AN, UK
| | - Rosalind E M Rickaby
- Department of Earth Sciences, South Parks Road, University of Oxford, Oxfordshire, OX1 3AN, UK
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9
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D'Agostino PM, Yeung ACY, Poljak A, David Waite T, Neilan BA. Comparative proteomics of the toxigenic diazotroph Raphidiopsis raciborskii (cyanobacteria) in response to iron. Environ Microbiol 2020; 23:405-414. [PMID: 33200490 DOI: 10.1111/1462-2920.15328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/13/2020] [Indexed: 11/30/2022]
Abstract
Raphidiopsis raciborskii is an invasive bloom-forming cyanobacteria with the flexibility to utilize atmospheric and fixed nitrogen. Since nitrogen-fixation has a high requirement for iron as an ezyme cofactor, we hypothesize that iron availability would determine the success of the species under nitrogen-fixing conditions. This study compares the proteomic response of cylindrospermopsin-producing and non-toxic strains of R. racibroskii to reduced iron concentrations, under nitrogen-fixing conditions, to examine any strain-specific adaptations that might increase fitness under these conditions. We also compared their proteomic responses at exponential and stationary growth phases to capture the changes throughout the growth cycle. Overall, the toxic strain was more competitive under Fe-starved conditions during exponential phase, with upregulated growth and transport-related proteins. The non-toxic strain showed reduced protein expression across multiple primary metabolism pathways. We propose that the increased expression of porin proteins during the exponential growth phase enables toxic strains to persist under Fe-starved conditions with this ability providing a potential explanation for the increased fitness of cylindrospermoipsin-producing strains during unfavourable environmental conditions.
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Affiliation(s)
- Paul M D'Agostino
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia.,Chair of Technical Biochemistry, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Anna C Y Yeung
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia.,School of Civil and Environmental Engineering, UNSW, Sydney, NSW, Australia
| | - Anne Poljak
- Bioanalytical Mass Spectrometry Facility, UNSW, Sydney, NSW, Australia
| | - Trevor David Waite
- School of Civil and Environmental Engineering, UNSW, Sydney, NSW, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia.,School of Environmental and Life Sciences, University of Newcastle, Newcastle, NSW, Australia
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10
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Zhang F, Hong H, Kranz SA, Shen R, Lin W, Shi D. Proteomic responses to ocean acidification of the marine diazotroph Trichodesmium under iron-replete and iron-limited conditions. PHOTOSYNTHESIS RESEARCH 2019; 142:17-34. [PMID: 31077001 DOI: 10.1007/s11120-019-00643-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 04/30/2019] [Indexed: 05/19/2023]
Abstract
Growth and dinitrogen (N2) fixation of the globally important diazotrophic cyanobacteria Trichodesmium are often limited by iron (Fe) availability in surface seawaters. To systematically examine the combined effects of Fe limitation and ocean acidification (OA), T. erythraeum strain IMS101 was acclimated to both Fe-replete and Fe-limited concentrations under ambient and acidified conditions. Proteomic analysis showed that OA affected a wider range of proteins under Fe-limited conditions compared to Fe-replete conditions. OA also led to an intensification of Fe deficiency in key cellular processes (e.g., photosystem I and chlorophyll a synthesis) in already Fe-limited T. erythraeum. This is a result of reallocating Fe from these processes to Fe-rich nitrogenase to compensate for the suppressed N2 fixation. To alleviate the Fe shortage, the diazotroph adopts a series of Fe-based economic strategies (e.g., upregulating Fe acquisition systems for organically complexed Fe and particulate Fe, replacing ferredoxin by flavodoxin, and using alternative electron flow pathways to produce ATP). This was more pronounced under Fe-limited-OA conditions than under Fe limitation only. Consequently, OA resulted in a further decrease of N2- and carbon-fixation rates in Fe-limited T. erythraeum. In contrast, Fe-replete T. erythraeum induced photosystem I (PSI) expression to potentially enhance the PSI cyclic flow for ATP production to meet the higher demand for energy to cope with the stress caused by OA. Our study provides mechanistic insight into the holistic response of the globally important N2-fixing marine cyanobacteria Trichodesmium to acidified and Fe-limited conditions of future oceans.
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Affiliation(s)
- Futing Zhang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Haizheng Hong
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen, Fujian, People's Republic of China
- College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Sven A Kranz
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Rong Shen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Wenfang Lin
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Dalin Shi
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China.
- Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen, Fujian, People's Republic of China.
- College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, People's Republic of China.
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11
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Shafiee RT, Snow JT, Zhang Q, Rickaby REM. Iron requirements and uptake strategies of the globally abundant marine ammonia-oxidising archaeon, Nitrosopumilus maritimus SCM1. THE ISME JOURNAL 2019; 13:2295-2305. [PMID: 31076641 PMCID: PMC6776035 DOI: 10.1038/s41396-019-0434-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/04/2019] [Accepted: 04/15/2019] [Indexed: 01/08/2023]
Abstract
Ammonia-oxidising archaea (AOA) mediate the rate-limiting step of nitrification, the central component of the marine nitrogen cycle that converts ammonia to nitrite then nitrate. Competition with phytoplankton for ammonium and light inhibition are considered to restrict AOA activity to below the photic zone, but observations of surface nitrification now demand a further understanding of the factors driving AOA distribution and activity. Pico- to nanomolar concentrations of iron (Fe) limit the growth of microorganisms in a significant portion of the world's surface oceans, yet there is no examination of the role of Fe in AOA growth despite the process of ammonia oxidation being considered to rely on the micronutrient. Here we investigate the Fe requirements and Fe uptake strategies of the Nitrosopumilus maritimus strain SCM1, a strain representative of globally abundant marine AOA. Using trace metal clean culturing techniques, we found that N. maritimus growth is determined by Fe availability, displaying a free inorganic Fe (Fe') half saturation constant 1-2 orders of magnitude greater for cell growth than numerous marine phytoplankton and heterotrophic bacterial species driven by a reduced affinity for Fe'. In addition, we discovered that whilst unable to produce siderophores to enhance access to Fe, N. maritimus is able to use the exogenous siderophore desferrioxamine B (DFB), likely through a reductive uptake pathway analogous to that demonstrated in phytoplankton. Our work suggests AOA growth in surface waters may be Fe limited and advances our understanding of AOA physiology on the cellular and mechanistic levels with implications for ecosystem dynamics and the biogeochemical N-cycle.
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Affiliation(s)
- Roxana T Shafiee
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK.
| | - Joseph T Snow
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK
| | - Qiong Zhang
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK
| | - Rosalind E M Rickaby
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxfordshire, OX1 3AN, UK
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12
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Li Q, Huisman J, Bibby TS, Jiao N. Biogeography of Cyanobacterial isiA Genes and Their Link to Iron Availability in the Ocean. Front Microbiol 2019; 10:650. [PMID: 31024472 PMCID: PMC6460047 DOI: 10.3389/fmicb.2019.00650] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 03/14/2019] [Indexed: 11/15/2022] Open
Abstract
The cyanobacterial iron-stress-inducible isiA gene encodes a chlorophyll-binding protein that provides flexibility in photosynthetic strategy enabling cells to acclimate to low iron availability. Here, we report on the diversity and abundance of isiA genes from 14 oceanic stations encompassing large natural gradients in iron availability. Synechococcus CRD1 and CRD2-like isiA genes were ubiquitously identified from tropical and subtropical waters of the Pacific, Atlantic, and Indian Oceans. The relative abundance of isiA-containing Synechococcus cells ranged from less than 10% of the total Synechococcus population in regions where iron is replete such as the North Atlantic subtropical gyre, to over 80% in low-iron but high-nitrate regions of the eastern equatorial Pacific. Interestingly, Synechococcus populations in regions with both low iron and low nitrate concentrations such as the subtropical gyres in the North Pacific and South Atlantic had a low relative abundance of the isiA gene. Indeed, fitting our data into a multiple regression model showed that ∼80% of the variation in isiA relative abundances can be explained by nitrate and iron concentrations, whereas no other environmental variables (temperature, salinity, Chl a) had a significant effect. Hence, isiA has a predictable biogeographical distribution, consistent with the perceived biological role of IsiA as an adaptation to low-iron conditions. Understanding such photosynthetic strategies is critical to our ability to accurately estimate primary production and map nutrient limitation on global scales.
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Affiliation(s)
- Qian Li
- State Key Laboratory of Marine Environmental Sciences, Institute of Marine Microbes and Ecosphere, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
- Center for Microbial Oceanography: Research and Education, Department of Oceanography, University of Hawai’i at Mānoa, Honolulu, HI, United States
| | - Jef Huisman
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Thomas S. Bibby
- School of Ocean and Earth Science, National Oceanography Centre Southampton, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Sciences, Institute of Marine Microbes and Ecosphere, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
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13
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Frischkorn KR, Haley ST, Dyhrman ST. Transcriptional and Proteomic Choreography Under Phosphorus Deficiency and Re-supply in the N 2 Fixing Cyanobacterium Trichodesmium erythraeum. Front Microbiol 2019; 10:330. [PMID: 30891009 PMCID: PMC6411698 DOI: 10.3389/fmicb.2019.00330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/08/2019] [Indexed: 01/27/2023] Open
Abstract
The N2 fixing cyanobacterium Trichodesmium is a critically important organism in oligotrophic marine ecosystems, supplying “new” nitrogen (N) to the otherwise N-poor tropical and subtropical regions where it occurs. Low concentrations of phosphorus (P) in these regions can constrain Trichodesmium distribution and N2 fixation rates. Physiological characterization of a single species in a mixed community can be challenging, and ‘omic approaches are increasingly important tools for tracking nutritional physiology in a taxon-specific manner. As such, studies examining the dynamics of gene and protein markers of physiology (e.g., nutrient stress) are critical for the application and interpretation of such ‘omic data in situ. Here we leveraged combined transcriptomics, proteomics, and enzyme activity assays to track the physiological response of Trichodesmium erythraeum IMS101 to P deficiency and subsequent P re-supply over 72 h of sampling. P deficiency resulted in differential gene expression, protein abundance, and enzyme activity that highlighted a synchronous shift in P physiology with increases in the transcripts and corresponding proteins for hydrolyzing organic phosphorus, taking up phosphate with higher affinity, and modulating intracellular P demand. After P deficiency was alleviated, gene expression of these biomarkers was reduced to replete levels within 4 h of P amendment. A number of these gene biomarkers were adjacent to putative pho boxes and their expression patterns were similar to a sphR response regulator. Protein products of the P deficiency biomarkers were slow to decline, with 84% of the original P deficient protein set still significantly differentially expressed after 72 h. Alkaline phosphatase activity tracked with proteins for this enzyme. With the rapid turnover time of transcripts, they appear to be good biomarkers of a P stress phenotype, whereas proteins, with a slower turnover time, may better reflect cellular activities. These results highlight the importance of validating and pairing transcriptome and proteome data that can be applied to physiological studies of key species in situ.
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Affiliation(s)
- Kyle R Frischkorn
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States.,Lamont-Doherty Earth Observatory, Palisades, NY, United States
| | - Sheean T Haley
- Lamont-Doherty Earth Observatory, Palisades, NY, United States
| | - Sonya T Dyhrman
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States.,Lamont-Doherty Earth Observatory, Palisades, NY, United States
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14
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Polyviou D, Machelett MM, Hitchcock A, Baylay AJ, MacMillan F, Moore CM, Bibby TS, Tews I. Structural and functional characterization of IdiA/FutA (Tery_3377), an iron-binding protein from the ocean diazotroph Trichodesmium erythraeum. J Biol Chem 2018; 293:18099-18109. [PMID: 30217820 PMCID: PMC6254336 DOI: 10.1074/jbc.ra118.001929] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 08/31/2018] [Indexed: 11/17/2022] Open
Abstract
Atmospheric nitrogen fixation by photosynthetic cyanobacteria (diazotrophs) strongly influences oceanic primary production and in turn affects global biogeochemical cycles. Species of the genus Trichodesmium are major contributors to marine diazotrophy, accounting for a significant proportion of the fixed nitrogen in tropical and subtropical oceans. However, Trichodesmium spp. are metabolically constrained by the availability of iron, an essential element for both the photosynthetic apparatus and the nitrogenase enzyme. Survival strategies in low-iron environments are typically poorly characterized at the molecular level, because these bacteria are recalcitrant to genetic manipulation. Here, we studied a homolog of the iron deficiency-induced A (IdiA)/ferric uptake transporter A (FutA) protein, Tery_3377, which has been used as an in situ iron-stress biomarker. IdiA/FutA has an ambiguous function in cyanobacteria, with its homologs hypothesized to be involved in distinct processes depending on their cellular localization. Using signal sequence fusions to GFP and heterologous expression in the model cyanobacterium Synechocystis sp. PCC 6803, we show that Tery_3377 is targeted to the periplasm by the twin-arginine translocase and can complement the deletion of the native Synechocystis ferric-iron ABC transporter periplasmic binding protein (FutA2). EPR spectroscopy revealed that purified recombinant Tery_3377 has specificity for iron in the Fe3+ state, and an X-ray crystallography–determined structure uncovered a functional iron substrate–binding domain, with Fe3+ pentacoordinated by protein and buffer ligands. Our results support assignment of Tery_3377 as a functional FutA subunit of an Fe3+ ABC transporter but do not rule out dual IdiA function.
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Affiliation(s)
- Despo Polyviou
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Moritz M Machelett
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom,; the Department of Biological Sciences, Faculty of Natural and Environmental Sciences, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom, and
| | - Andrew Hitchcock
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Alison J Baylay
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Fraser MacMillan
- the School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - C Mark Moore
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Thomas S Bibby
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Ivo Tews
- the Department of Biological Sciences, Faculty of Natural and Environmental Sciences, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom, and.
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15
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Polyviou D, Baylay AJ, Hitchcock A, Robidart J, Moore CM, Bibby TS. Desert Dust as a Source of Iron to the Globally Important Diazotroph Trichodesmium. Front Microbiol 2018; 8:2683. [PMID: 29387046 PMCID: PMC5776111 DOI: 10.3389/fmicb.2017.02683] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/22/2017] [Indexed: 12/22/2022] Open
Abstract
The marine cyanobacterium Trichodesmium sp. accounts for approximately half of the annual ‘new’ nitrogen introduced to the global ocean but its biogeography and activity is often limited by the availability of iron (Fe). A major source of Fe to the open ocean is Aeolian dust deposition in which Fe is largely comprised of particles with reduced bioavailability over soluble forms of Fe. We report that Trichodesmium erythraeum IMS101 has improved growth rate and photosynthetic physiology and down-regulates Fe-stress biomarker genes when cells are grown in the direct vicinity of, rather than physically separated from, Saharan dust particles as the sole source of Fe. These findings suggest that availability of non-soluble forms of dust-associated Fe may depend on cell contact. Transcriptomic analysis further reveals unique profiles of gene expression in all tested conditions, implying that Trichodesmium has distinct molecular signatures related to acquisition of Fe from different sources. Trichodesmium thus appears to be capable of employing specific mechanisms to access Fe from complex sources in oceanic systems, helping to explain its role as a key microbe in global biogeochemical cycles.
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Affiliation(s)
- Despo Polyviou
- Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton, United Kingdom
| | - Alison J Baylay
- Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton, United Kingdom
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Sheffield, United Kingdom
| | - Julie Robidart
- Ocean Technology and Engineering Group, National Oceanography Centre, Southampton, United Kingdom
| | - C M Moore
- Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton, United Kingdom
| | - Thomas S Bibby
- Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton, United Kingdom
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16
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Nutrient-Colimited Trichodesmium as a Nitrogen Source or Sink in a Future Ocean. Appl Environ Microbiol 2018; 84:AEM.02137-17. [PMID: 29180365 DOI: 10.1128/aem.02137-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/16/2017] [Indexed: 11/20/2022] Open
Abstract
Nitrogen-fixing (N2) cyanobacteria provide bioavailable nitrogen to vast ocean regions but are in turn limited by iron (Fe) and/or phosphorus (P), which may force them to employ alternative nitrogen acquisition strategies. The adaptive responses of nitrogen fixers to global-change drivers under nutrient-limited conditions could profoundly alter the current ocean nitrogen and carbon cycles. Here, we show that the globally important N2 fixer Trichodesmium fundamentally shifts nitrogen metabolism toward organic-nitrogen scavenging following long-term high-CO2 adaptation under iron and/or phosphorus (co)limitation. Global shifts in transcripts and proteins under high-CO2/Fe-limited and/or P-limited conditions include decreases in the N2-fixing nitrogenase enzyme, coupled with major increases in enzymes that oxidize trimethylamine (TMA). TMA is an abundant, biogeochemically important organic nitrogen compound that supports rapid Trichodesmium growth while inhibiting N2 fixation. In a future high-CO2 ocean, this whole-cell energetic reallocation toward organic nitrogen scavenging and away from N2 fixation may reduce new-nitrogen inputs by Trichodesmium while simultaneously depleting the scarce fixed-nitrogen supplies of nitrogen-limited open-ocean ecosystems.IMPORTANCE Trichodesmium is among the most biogeochemically significant microorganisms in the ocean, since it supplies up to 50% of the new nitrogen supporting open-ocean food webs. We used Trichodesmium cultures adapted to high-CO2 conditions for 7 years, followed by additional exposure to iron and/or phosphorus (co)limitation. We show that "future ocean" conditions of high CO2 and concurrent nutrient limitation(s) fundamentally shift nitrogen metabolism away from nitrogen fixation and instead toward upregulation of organic nitrogen-scavenging pathways. We show that the responses of Trichodesmium to projected future ocean conditions include decreases in the nitrogen-fixing nitrogenase enzymes coupled with major increases in enzymes that oxidize the abundant organic nitrogen source trimethylamine (TMA). Such a shift toward organic nitrogen uptake and away from nitrogen fixation may substantially reduce new-nitrogen inputs by Trichodesmium to the rest of the microbial community in the future high-CO2 ocean, with potential global implications for ocean carbon and nitrogen cycling.
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17
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Hutchins DA, Fu F, Walworth NG, Lee MD, Saito MA, Webb EA. Comment on "The complex effects of ocean acidification on the prominent N 2-fixing cyanobacterium Trichodesmium". Science 2017; 357:357/6356/eaao0067. [PMID: 28912213 DOI: 10.1126/science.aao0067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 08/07/2017] [Indexed: 11/02/2022]
Abstract
Hong et al (Reports, 5 May 2017, p. 527) suggested that previous studies of the biogeochemically significant marine cyanobacterium Trichodesmium showing increased growth and nitrogen fixation at projected future high CO2 levels suffered from ammonia or copper toxicity. They reported that these rates instead decrease at high CO2 when contamination is alleviated. We present and discuss results of multiple published studies refuting this toxicity hypothesis.
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Affiliation(s)
- David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
| | - Feixue Fu
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Nathan G Walworth
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Michael D Lee
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Mak A Saito
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
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18
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Walworth NG, Fu FX, Webb EA, Saito MA, Moran D, Mcllvin MR, Lee MD, Hutchins DA. Mechanisms of increased Trichodesmium fitness under iron and phosphorus co-limitation in the present and future ocean. Nat Commun 2016; 7:12081. [PMID: 27346420 PMCID: PMC4931248 DOI: 10.1038/ncomms12081] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/27/2016] [Indexed: 02/07/2023] Open
Abstract
Nitrogen fixation by cyanobacteria supplies critical bioavailable nitrogen to marine ecosystems worldwide; however, field and lab data have demonstrated it to be limited by iron, phosphorus and/or CO2. To address unknown future interactions among these factors, we grew the nitrogen-fixing cyanobacterium Trichodesmium for 1 year under Fe/P co-limitation following 7 years of both low and high CO2 selection. Fe/P co-limited cell lines demonstrated a complex cellular response including increased growth rates, broad proteome restructuring and cell size reductions relative to steady-state growth limited by either Fe or P alone. Fe/P co-limitation increased abundance of a protein containing a conserved domain previously implicated in cell size regulation, suggesting a similar role in Trichodesmium. Increased CO2 further induced nutrient-limited proteome shifts in widespread core metabolisms. Our results thus suggest that N2-fixing microbes may be significantly impacted by interactions between elevated CO2 and nutrient limitation, with broad implications for global biogeochemical cycles in the future ocean. Cyanobacterial nitrogen fixation supplies bioavailable nitrogen to marine ecosystems, but the mechanisms governing iron and phosphorus co-limitation in elevated CO2 remain unknown. Here, the authors show a complex cellular response to co-limitation characterized by changes in growth, cell size, and the proteome.
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Affiliation(s)
- Nathan G Walworth
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089, USA
| | - Fei-Xue Fu
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089, USA
| | - Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089, USA
| | - Mak A Saito
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
| | - Dawn Moran
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
| | - Matthew R Mcllvin
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA
| | - Michael D Lee
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089, USA
| | - David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089, USA
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