CoChat
Sign Up
Cited by 2Microbial Community Ecology and PhysiologyProtist diversity and phylogenyMarine Plankton and Biogeochemistry

The DOI matches its Crossref record; 1 of the 1 references it cites were found in a registry or an index.

Sulfated mannan of diatoms selects host-specific microbiota in the sunlit ocean

Open access
Krull, J., Sidhu, C., Solanki, V., Bligh, M., Rößler, L., Singh, R. K., Huang, G., Robb, C. S., Teeling, H., Seeberger, P. H., Schweder, T., Crawford, C. J., Hehemann, J.-H.·2026·Microbiome
DOI 10.1186/s40168-026-02379-9PMC PMC13063451

Published version of a preprint

Open this paper in CoChat — free account

Abstract

Background: Diatoms, a keystone phylum in Earth’s ecosystems, are responsible for substantial oxygen production and the fixation of carbon dioxide in the form of carbohydrates that fuel global food webs. They host diverse prokaryotes, yet how diatoms preferentially recruit those with complementary metabolic traits remains unknown. Results: We discovered that diatoms exude a C6-sulfated α-1,3-mannan that serves as a selective carbon source for adapted Polaribacter . Its structure was resolved using NMR spectroscopy, chromatography, chemical synthesis, and enzymatic dissection. Biochemical, physiological, and structural analyses demonstrated, that specialized Bacteroidota employ a four-enzyme pathway to metabolize this glycan. Metagenomic and transcriptomic data revealed that sulfated mannan utilization loci are globally abundant and actively expressed in surface ocean bacterioplankton. Because this mannan provides only carbon, oxygen, sulfur, and hydrogen, bacteria must obtain other essential elements elsewhere, reinforcing metabolic interdependence. Conclusions: Together, these results define a chemically specific interaction between diatoms and specialized bacteria that is mediated by a single sulfated polysaccharide and a dedicated four-enzyme degradation pathway. Presence of this pathway in marine metagenomes and transcriptomes indicates that a sulfated mannan from diatoms exerts selection pressure in the sunlit ocean microbiome.

Overview

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1186/s40168-026-02379-9

Cites

1 of 1 references verified0 citation errors · 0 not checkable

Statistics

Verification

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Citations

Cites

Flagged first, then by citations

Research works printed but not linked: 88

  1. Nelson D, Tréguer P, Brzezinski M, Leynaert A, Quéguiner B, Nelson DMD, Tréguer P, Brzezinski MA, Leynaert A, Queguiner B, Tréguer P. Production and dissolution of biogenic silica in the ocean: revised global estimates, comparison with regional data and relationship to biogenic sedimentation. Glob Biogeochem Cycle 9: 359–372. Global Biogeochemical Cycles. 1995;9:359–732. · DOI
  2. Myklestad S, Holm-Hansen O, Vårum KM, Volcani BE. Rate of release of extracellular amino acids and carbohydrates from the marine diatom Chaetoceros affinis. J Plankton Res. 1989;11:763–73. · DOI
  3. Gaignard C, et al. Screening of marine microalgae: Investigation of new exopolysaccharide producers. Algal Research. 2019;44:101711. · DOI
  4. Vidal-Melgosa S, et al. Diatom fucan polysaccharide precipitates carbon during algal blooms. Nat Commun. 2021;12:1150. · DOI
  5. Sichert A, et al. Verrucomicrobia use hundreds of enzymes to digest the algal polysaccharide fucoidan. Nat Microbiol. 2020;5:1026–39. · DOI
  6. Gaignard C, et al. New horizons in culture and valorization of red microalgae. Biotechnol Adv. 2019;37:193–222. · DOI
  7. Bligh M, Nguyen N, Buck-Wiese H, Vidal-Melgosa S, Hehemann J-H. Structures and functions of algal glycans shape their capacity to sequester carbon in the ocean. Curr Opin Chem Biol. 2022;71:102204. · DOI
  8. Aluwihare LI, Repeta DJ. A comparison of the chemical characteristics of oceanic DOM and extracellular DOM produced by marine algae. Mar Ecol Prog Ser. 1999;186:105–17. · DOI
  9. Engel A, Thoms S, Riebesell U, Rochelle-Newall E, Zondervan I. Polysaccharide aggregation as a potential sink of marine dissolved organic carbon. Nature. 2004;428:929–32. · DOI
  10. Amon RMW, Fitznar H-P, Benner R. Linkages among the bioreactivity, chemical composition, and diagenetic state of marine dissolved organic matter. Limnol Oceanogr. 2001;46:287–97. · DOI
  11. Myklestad SM. Release of extracellular products by phytoplankton with special emphasis on polysaccharides. Sci Total Environ. 1995;165:155–64. · DOI
  12. Abdullahi AS, Underwood GJC, Gretz MR. Extracellular matrix assembly in diatoms (BACILLARIOPHYCEAE). V. Environmental effects on polysaccharide synthesis in the model diatom, Phaeodactylum tricornutum1. J Phycol. 2006;42:363–78. · DOI
  13. Beidler I, et al. Marine bacteroidetes use a conserved enzymatic cascade to digest diatom β-mannan. The ISME Journal. 2022. https://doi.org/10.1038/s41396-022-01342-4. · DOI
  14. Zeugner LE, Krüger K, Barrero-Canosa J, Amann RI, Fuchs BM. In situ visualization of glycoside hydrolase family 92 genes in marine flavobacteria. ISME Commun. 2021;1:81. · DOI
  15. Sidhu C, et al. Dissolved storage glycans shaped the community composition of abundant bacterioplankton clades during a North Sea spring phytoplankton bloom. Microbiome. 2023;11:77. · DOI
  16. de Vargas C, et al. Eukaryotic plankton diversity in the sunlit ocean. Science. 2015;348:1261605. · DOI
  17. Malviya S, et al. Insights into global diatom distribution and diversity in the world’s ocean. Proc Natl Acad Sci. 2016;113:E1516–25. · DOI
  18. Staley JT, Gosink JJ. Poles apart: biodiversity and biogeography of sea ice bacteria. Annu Rev Microbiol. 1999;53:189–215. · DOI
  19. Avcı B, Krüger K, Fuchs BM, Teeling H, Amann RI. Polysaccharide niche partitioning of distinct Polaribacter clades during North Sea spring algal blooms. ISME J. 2020;14:1369–83. · DOI
  20. Kappelmann L, et al. Polysaccharide utilization loci of North Sea Flavobacteriia as basis for using SusC/D-protein expression for predicting major phytoplankton glycans. ISME J. 2019;13:76–91. · DOI
  21. Wang F-Q, et al. Particle-attached bacteria act as gatekeepers in the decomposition of complex phytoplankton polysaccharides. Microbiome. 2024;12:32. · DOI
  22. Francis TB, et al. Changing expression patterns of TonB-dependent transporters suggest shifts in polysaccharide consumption over the course of a spring phytoplankton bloom. ISME J. 2021;15:2336–50. · DOI
  23. Hevia-Orube J, et al. Molecular and morphological analyses of solitary forms of brackish Thalassiosiroid diatoms (Coscinodiscophyceae), with emphasis on their phenotypic plasticity. Eur J Phycol. 2016;51:11–30. · DOI
  24. Vidal-Melgosa S, et al. Diatom fucan polysaccharide precipitates carbon during algal blooms. Nat Commun. 2021;12:1150. · DOI
  25. Ford C, Percival E. 1299. Carbohydrates of Phaeodactylum tricornutum. Part II. A sulphated glucuronomannan. J Chem Soc. 1965:7042–7046. https://doi.org/10.1039/JR9650007042. · DOI
  26. Le Costaouëc T, Unamunzaga C, Mantecon L, Helbert W. New structural insights into the cell-wall polysaccharide of the diatom Phaeodactylum tricornutum. Algal Res. 2017;26:172–9. · DOI
  27. Kloareg B, Badis Y, Cock JM, Michel G. Role and Evolution of the Extracellular Matrix in the Acquisition of Complex Multicellularity in Eukaryotes: A Macroalgal Perspective. https://doi.org/10.3390/genes12071059. · DOI
  28. Le Mai Hoang K, et al. Traceless photolabile linker expedites the chemical synthesis of complex oligosaccharides by automated glycan assembly. J Am Chem Soc. 2019;141:9079–86. · DOI
  29. Crawford CJ, et al. Activity-Based Tracking of Glycan Turnover in Microbiomes. J Am Chem Soc. 2025;147:25799–805. · DOI
  30. Plante OJ, Palmacci ER, Seeberger PH. Automated solid-phase synthesis of oligosaccharides. Science. 2001;291:1523–7. · DOI
  31. Plante OJ, Andrade RB, Seeberger PH. Synthesis and use of glycosyl phosphates as glycosyl donors. Org Lett. 1999;1:211–4. · DOI
  32. Hahnke RL, et al. Dilution cultivation of marine heterotrophic bacteria abundant after a spring phytoplankton bloom in the North Sea. Environ Microbiol. 2015;17:3515–26. · DOI
  33. Richter M, Rosselló-Móra R, Oliver Glöckner F, Peplies J. JSpeciesWS: a web server for prokaryotic species circumscription based on pairwise genome comparison. Bioinformatics. 2016;32:929–31. · DOI
  34. Kwon YK, et al. Ochrovirga pacifica gen. nov., sp. nov., a novel agar-lytic marine bacterium of the family Flavobacteriaceae isolated from a seaweed. Curr Microbiol. 2014;69:445–50. · DOI
  35. Varki A, et al. Symbol Nomenclature for Graphical Representations of Glycans. Glycobiology. 2015;25:1323–4. · DOI
  36. Robb CS, Mystkowska AA, Hehemann JH. Crystal structure of a marine glycoside hydrolase family 99-related protein lacking catalytic machinery. Protein Sci. 2017;26:2445–50. · DOI
  37. Barbeyron T, et al. Matching the Diversity of Sulfated Biomolecules: Creation of a Classification Database for Sulfatases Reflecting Their Substrate Specificity. PLoS ONE. 2016;11:e0164846. · DOI
  38. Drula E, et al. The carbohydrate-active enzyme database: functions and literature. Nucleic Acids Res. 2022;50:D571–7. · DOI · Paper page
  39. Davies G, Henrissat B. Structures and mechanisms of glycosyl hydrolases. Structure. 1995;3:853–9. · DOI
  40. Hettle AG, et al. The Molecular Basis of Polysaccharide Sulfatase Activity and a Nomenclature for Catalytic Subsites in this Class of Enzyme. Structure. 2018;26:747-758.e744. · DOI
  41. Zhu Y, et al. Mechanistic insights into a Ca2+-dependent family of alpha-mannosidases in a human gut symbiont. Nat Chem Biol. 2010;6:125–32. · DOI
  42. Teufel F, et al. SignalP 6.0 predicts all five types of signal peptides using protein language models. Nat Biotechnol. 2022;40:1023–5. · DOI
  43. Cartmell A, et al. How members of the human gut microbiota overcome the sulfation problem posed by glycosaminoglycans. Proc Natl Acad Sci U S A. 2017;114:7037–42. · DOI
  44. Robb CS, et al. Metabolism of a hybrid algal galactan by members of the human gut microbiome. Nat Chem Biol. 2022;18:501–10. · DOI
  45. Kim KT, Rioux LE, Turgeon SL. Alpha-amylase and alpha-glucosidase inhibition is differentially modulated by fucoidan obtained from Fucus vesiculosus and Ascophyllum nodosum. Phytochemistry. 2014;98:27–33. · DOI
  46. Hehemann J-H, et al. Biochemical and Structural Characterization of the Complex Agarolytic Enzyme System from the Marine Bacterium Zobellia galactanivorans*. J Biol Chem. 2012;287:30571–84. · DOI
  47. Correc G, Hehemann JH, Czjzek M, Helbert W. Structural analysis of the degradation products of porphyran digested by Zobellia galactanivorans beta-porphyranase A. Carbohyd Polym. 2011;83:277–83. · DOI
  48. Baltar F, Zhao Z, Herndl GJ. Potential and expression of carbohydrate utilization by marine fungi in the global ocean. Microbiome. 2021;9:106. · DOI
  49. Chrismas N, Cunliffe M. Depth-dependent mycoplankton glycoside hydrolase gene activity in the open ocean—evidence from the Tara Oceans eukaryote metatranscriptomes. ISME J. 2020;14:2361–5. · DOI
  50. Breyer E, Zhao Z, Herndl GJ, Baltar F. Global contribution of pelagic fungi to protein degradation in the ocean. Microbiome. 2022;10:143. · DOI
  51. Becker S, Scheffel A, Polz MF, Hehemann JH. Accurate quantification of laminarin in marine organic matter with enzymes from marine microbes. Appl Environ Microb. 2017;83:e03389. · DOI
  52. Unfried F, et al. Adaptive mechanisms that provide competitive advantages to marine bacteroidetes during microalgal blooms. ISME J. 2018;12:2894–906. · DOI
  53. Smetacek V, Zingone A. Green and golden seaweed tides on the rise. Nature. 2013;504:84–8. · DOI · Paper page
  54. Reisky L, et al. A marine bacterial enzymatic cascade degrades the algal polysaccharide ulvan. Nat Chem Biol. 2019;15:803–12. · DOI
  55. Nedashkovskaya OI. Formosa agariphila sp. nov., a budding bacterium of the family Flavobacteriaceae isolated from marine environments, and emended description of the genus Formosa. Int J Syst Evol Microbiol. 2006;56:161–7. · DOI
  56. Mann AJ, et al. The genome of the alga-associated marine flavobacterium Formosa agariphila KMM 3901T reveals a broad potential for degradation of algal polysaccharides. Appl Environ Microbiol. 2013;79:6813–22. · DOI
  57. Armbrust EV. The life of diatoms in the world's oceans. Nature. 2009;459:185-192. · DOI · Paper page
  58. de Vargas C, et al. Eukaryotic plankton diversity in the sunlit ocean. Science. 2015;348:1261605. · DOI
  59. Reisky L, et al. A marine bacterial enzymatic cascade degrades the algal polysaccharide ulvan. Nat Chem Biol. 2019;15:803-812. · DOI
  60. Pérez-Cruz C, et al. Mechanisms of recalcitrant fucoidan breakdown in marine Planctomycetota. Nat Commun. 2024;15:10906. · DOI
  61. Leblanc K, et al. A global diatom database – abundance, biovolume and biomass in the world ocean. Earth Syst Sci Data. 2012;4:149–65. · DOI
  62. Giovannoni SJ. SAR11 bacteria: the most abundant plankton in the Oceans. Annu Rev Mar Sci. 2017;9:231–55. · DOI
  63. Dadon-Pilosof A, et al. Surface properties of SAR11 bacteria facilitate grazing avoidance. Nat Microbiol. 2017;2:1608–15. · DOI
  64. Yawata Y, et al. Competition-dispersal tradeoff ecologically differentiates recently speciated marine bacterioplankton populations. Proc Natl Acad Sci U S A. 2014;111:5622–7. · DOI
  65. Shapiro BJ, et al. Population genomics of early events in the ecological differentiation of bacteria. Science. 2012;336:48–51. · DOI
  66. Purugganan MD. What is domestication? Trends Ecol Evol. 2022;37:663–71. · DOI
  67. Zeder MA. Core questions in domestication research. Proc Natl Acad Sci USA. 2015;112:3191–8. · DOI
  68. Wheeler KM, et al. Mucin glycans attenuate the virulence of Pseudomonas aeruginosa in infection. Nat Microbiol. 2019;4:2146–54. · DOI
  69. Tian T, et al. Sucrose triggers a novel signaling cascade promoting Bacillus subtilis rhizosphere colonization. ISME J. 2021;15:2723–37. · DOI
  70. Teeling H, et al. Recurring patterns in bacterioplankton dynamics during coastal spring algae blooms. Elife. 2016;5:e11888. · DOI
  71. Reintjes G, et al. Short-term changes in polysaccharide utilization mechanisms of marine bacterioplankton during a spring phytoplankton bloom. Environ Microbiol. 2020;22:1884–900. · DOI
  72. Langmead B, Salzberg SL. Fast gapped-read alignment with Bowtie 2. Nat Methods. 2012;9:357–9. · DOI · Paper page
  73. Harrison PJ, Waters RE, Taylor FJR. A broad spectrum artificial sea water medium for coastal and open ocean phytoplankton1. J Phycol. 1980;16:28–35.
  74. Engel A, Händel N. A novel protocol for determining the concentration and composition of sugars in particulate and in high molecular weight dissolved organic matter (HMW-DOM) in seawater. Mar Chem. 2011;127:180–91. · DOI
  75. Shilling PJ, et al. Improved designs for pET expression plasmids increase protein production yield in Escherichia coli. Commun Biol. 2020;3:214. · DOI
  76. Almagro Armenteros JJ, et al. SignalP 5.0 improves signal peptide predictions using deep neural networks. Nat Biotechnol. 2019;37:420–423. · DOI
  77. Carrico IS, Carlson BL, Bertozzi CR. Introducing genetically encoded aldehydes into proteins. Nat Chem Biol. 2007;3:321–2. · DOI
  78. Solanki V, et al. Glycoside hydrolase from the GH76 family indicates that marine Salegentibacter sp. Hel_I_6 consumes alpha-mannan from fungi. ISME J. 2022;16:1818–1830. · DOI
  79. Hehemann JH, et al. Transfer of carbohydrate-active enzymes from marine bacteria to Japanese gut microbiota. Nature. 2010;464:908–12. · DOI · Paper page
  80. Becker S, Hehemann J-H. Laminarin quantification in microalgae with enzymes from marine microbes. Bio-Protoc. 2018;8:e2666. · DOI
  81. Crawford CJ, et al. Automated Synthesis of Algal Fucoidan Oligosaccharides. J Am Chem Soc. 2024;146:18320–30. · DOI
  82. Crawford C, Oscarson S. Optimized Conditions for the Palladium-Catalyzed Hydrogenolysis of Benzyl and Naphthylmethyl Ethers: Preventing Saturation of Aromatic Protecting Groups. Eur J Org Chem. 2020;2020:3332–7. · DOI
  83. McCoy AJ, et al. Phaser crystallographic software. J Appl Crystallogr. 2007;40:658–74. · DOI · Paper page
  84. Cowtan K. The buccaneer software for automated model building. 1. Tracing protein chains. Acta Crystallogr D Biol Crystallogr. 2006;62:1002–11. · DOI
  85. Murshudov GN, et al. REFMAC5 for the refinement of macromolecular crystal structures. Acta Crystallogr D Biol Crystallogr. 2011;67:355–67. · DOI
  86. Emsley P, Lohkamp B, Scott WG, Cowtan K. Features and development of Coot. Acta Crystallogr D Biol Crystallogr. 2010;66:486–501. · DOI · Paper page
  87. Hahnke RL, Harder J. Phylogenetic diversity of Flavobacteria isolated from the North Sea on solid media. Syst Appl Microbiol. 2013;36:497–504. · DOI
  88. Robb M, Hobbs JK, Boraston AB. Separation and visualization of glycans by fluorophore-assisted carbohydrate electrophoresis. Methods Mol Biol. 2017;1588:215–21. · DOI

Metadata

Authors
Krull, J., Sidhu, C., Solanki, V., Bligh, M., Rößler, L., Singh, R. K., Huang, G., Robb, C. S., Teeling, H., Seeberger, P. H., Schweder, T., Crawford, C. J., & Hehemann, J.-H.
Affiliations
  • University of Bremen (DE)
  • Carl von Ossietzky Universität Oldenburg (DE)
  • Max Planck Institute for Marine Microbiology (DE)
  • Max Planck Institute of Colloids and Interfaces (DE)
  • Universität Greifswald (DE)
  • Trinity College Dublin (IE)
Corresponding author
  • Crawford, C. J.
  • Hehemann, J.-H.
ORCID
Venue
Microbiome
Publisher
Springer Science and Business Media LLC
Published
2026-03-26
Volume
14
Issue
1
ISSN
2049-2618 (ISSN-L)
DOI
10.1186/s40168-026-02379-9
PMC
PMC13063451
OpenAlex
W7140521783
Cited by
2
References
1
Citations by year
2026: 2
FWCI
6.94
Type
journal article
Language
en
Update notices
correction (2026-06-06)
Open access
Licence
Locations
  • Microbiome (publishedVersion, cc-by)
  • Research Square (acceptedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • MPG.PuRe (Max Planck Society) (submittedVersion, other-oa)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • MSCA (101029842)
  • Deutsche Forschungsgemeinschaft (Project number 570219261)
  • DFG (HE 7217/5-1)
  • ERC (101044738)
  • Universität Bremen
Topics
  • Physical Sciences › Environmental Science › Ecology › Microbial Community Ecology and Physiology
  • Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Protist diversity and phylogeny
  • Physical Sciences › Earth and Planetary Sciences › Oceanography › Marine Plankton and Biogeochemistry
Keywords
diatoms, Polaribacter, Bacteroidetes, diatom-bacteria interactions, marine bacterioplankton, exudate, marine microbiome
MeSH terms
Bacteria, Mannans, Oceans and Seas, Seawater, Sulfates, Diatoms, Metagenome, Metagenomics, Microbiota

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review