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Extensive membrane systems at the host–arbuscular mycorrhizal fungus interface


During arbuscular mycorrhizal (AM) symbiosis, cells within the root cortex develop a matrix-filled apoplastic compartment in which differentiated AM fungal hyphae called arbuscules reside. Development of the compartment occurs rapidly, coincident with intracellular penetration and rapid branching of the fungal hypha, and it requires much of the plant cell’s secretory machinery to generate the periarbuscular membrane that delimits the compartment. Despite recent advances, our understanding of the development of the periarbuscular membrane and the transfer of molecules across the symbiotic interface is limited. Here, using electron microscopy and tomography, we reveal that the periarbuscular matrix contains two types of membrane-bound compartments. We propose that one of these arises as a consequence of biogenesis of the periarbuscular membrane and may facilitate movement of molecules between symbiotic partners. Additionally, we show that the arbuscule contains massive arrays of membrane tubules located between the protoplast and the cell wall. We speculate that these tubules may provide the absorptive capacity needed for nutrient assimilation and possibly water absorption to enable rapid hyphal expansion.

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Fig. 1: Extensions of the PAM form vesicular–tubular compartments in the PAS.
Fig. 2: Electron tomography of an IMC.
Fig. 3: Integral membrane proteins outline the PAM but also accumulate in distinct regions.
Fig. 4: An extensive mass of membrane tubules extend beyond the protoplast of the arbuscule but remain within the fungal cell wall.
Fig. 5: Electron tomography of fungal tubules.
Fig. 6: IMCs and fungal membrane tubules in M. truncatula exo70i mutant.

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Data Availability

The data that support the findings of this study are available from the corresponding author upon request.


  1. Gutjahr, C. & Parniske, M. in Annual Review of Cell and Developmental Biology Vol. 29 (ed. Schekman, R.) 593–617 (Annual Reviews, Palo Alto, 2013).

  2. Harrison, M. J. & Ivanov, S. Exocytosis for endosymbiosis: membrane trafficking pathways for development of symbiotic membrane compartments. Curr. Opin. Plant Biol. 38, 101–108 (2017).

    Article  CAS  Google Scholar 

  3. MacLean, A. M., Bravo, A. & Harrison, M. J. Plant signaling and metabolic pathways enabling arbuscular mycorrhizal symbiosis. Plant Cell 29, 2319–2335 (2017).

    Article  CAS  Google Scholar 

  4. Bonfante-Fasolo, P., Vian, B., Perotto, S., Faccio, A. & Knox, J. P. Cellulose and pectin localization in roots of mycorrhizal Allium porrum: labelling continuity between host cell wall and interfacial material. Planta 180, 537–547 (1990).

    Article  CAS  Google Scholar 

  5. Bonfante, P. & Perotto, S. Strategies of arbuscular mycorrhizal fungi when infecting host plants. New Phytol. 130, 3–21 (1995).

    Article  Google Scholar 

  6. Cox, G. C. & Sanders, F. E. Ultrastructure of the host-fungus interface in a vesicular-arbuscular mycorrhiza. New Phytol. 73, 901–912 (1974).

    Article  Google Scholar 

  7. Dexheimer, J., Gianinazzi, S. & Gianinazzi-Pearson, V. Ultrastructural cytochemistry of the host-fungus interfaces in the endomycorrhizal association Glomus mosseae/Allium cepa. Z. Pflanzenphysiol. 92, 191–206 (1979).

    Article  Google Scholar 

  8. Bonfante-Fasolo, P. in VA Mycorrhizae (eds Powell, C. L. & Bagyaraj, D. J.) 5–33 (CRC, Boca Raton, 1984).

  9. Dexheimer, J., Marx, C., Gianinazzipearson, V. & Gianinazzi, S. Ultracytological studies of plasmalemma formations produced by host and fungus in vesicular arbuscular mycorrhizae. Cytologia 50, 461–471 (1985).

    Article  Google Scholar 

  10. Bracker, C. E. Ultrastructure of fungi. Annu. Rev. Phytopathol. 5, 343–372 (1967).

    Article  Google Scholar 

  11. Marchant, R. & Moore, R. T. Lomasomes and plasmalemmasomes in fungi. Protoplasma 76, 235–247 (1973).

    Article  Google Scholar 

  12. Gianinazzi-Pearson, V., Dexheimer, J., Gianinazzi, S. & Jeanmaire, C. Plasmalemma structure and function in endomycorrhizal symbioses. Z. Pflanzenphysiol. 114, 201–205 (1984).

    Article  CAS  Google Scholar 

  13. Pumplin, N., Zhang, X., Noar, R. D. & Harrison, M. J. Polar localization of a symbiosis-specific phosphate transporter is mediated by a transient reorientation of secretion. Proc. Natl Acad. Sci. USA 109, E665–E672 (2012).

    Article  CAS  Google Scholar 

  14. Genre, A., Chabaud, M., Faccio, A., Barker, D. G. & Bonfante, P. Prepenetration apparatus assembly precedes and predicts the colonization patterns of arbuscular mycorrhizal fungus within the root cortex of both Medicago truncatula and Daucus carota. Plant Cell 20, 1407–1420 (2008).

    Article  CAS  Google Scholar 

  15. Zhang, X. C., Pumplin, N., Ivanov, S. & Harrison, M. J. EXO70I Is required for development of a sub-domain of the periarbuscular membrane during arbuscular mycorrhizal symbiosis. Curr. Biol. 25, 2189–2195 (2015).

    Article  CAS  Google Scholar 

  16. Ivanov, S. et al. Rhizobium-legume symbiosis shares an exocytotic pathway required for arbuscule formation. Proc. Natl Acad. Sci. USA 109, 8316–8321 (2012).

    Article  CAS  Google Scholar 

  17. Huisman, R. et al. A symbiosis-dedicated SYNTAXIN OF PLANTS 13II isoform controls the formation of a stable host-microbe interface in symbiosis. New Phytol. 211, 1338–1351 (2016).

    Article  CAS  Google Scholar 

  18. Pan, H. et al. A symbiotic SNARE protein generated by alternative termination of transcription. Nat. Plants 2, 15197 (2016).

    Article  CAS  Google Scholar 

  19. Javot, H., Penmetsa, R. V., Terzaghi, N., Cook, D. R. & Harrison, M. J. A. Medicago truncatula phosphate transporter indispensable for the arbuscular mycorrhizal symbiosis. Proc. Natl Acad. Sci. USA 104, 1720–1725 (2007).

    Article  CAS  Google Scholar 

  20. Yang, S. Y. et al. Nonredundant regulation of rice arbuscular mycorrhizal symbiosis by two members of the phosphate transporter1 gene family. Plant Cell 24, 4236–4251 (2012).

    Article  CAS  Google Scholar 

  21. Krajinski, F. et al. The H+-ATPase HA1 of Medicago truncatula Is essential for phosphate transport and plant growth during arbuscular mycorrhizal symbiosis. Plant Cell 26, 1808–1817 (2014).

    Article  CAS  Google Scholar 

  22. Wang, E. T. et al. A H+-ATPase that energizes nutrient uptake during mycorrhizal symbioses in rice and Medicago truncatula. Plant Cell 26, 1818–1830 (2014).

    Article  CAS  Google Scholar 

  23. Wewer, V., Brands, M. & Doermann, P. Fatty acid synthesis and lipid metabolism in the obligate biotrophic fungus Rhizophagus irregularis during mycorrhization of Lotus japonicus. Plant J. 79, 398–412 (2014).

    Article  CAS  Google Scholar 

  24. Bravo, A., Brands, M., Wewer, V., Doermann, P. & Harrison, M. J. Arbuscular mycorrhiza-specific enzymes FatM and RAM2 fine tune lipid biosynthesis to promote development of arbuscular mycorrhiza. New Phytol. 214, 1631–1645 (2017).

    Article  CAS  Google Scholar 

  25. Jiang, Y. et al. Plants transfer lipids to sustain colonization by mutualistic mycorrhizal and parasitic fungi. Science 356, 1172–1175 (2017).

    Article  CAS  Google Scholar 

  26. Keymer, A. et al. Lipid transfer from plants to arbuscular mycorrhiza fungi. eLife 6, e29107 (2017).

    Article  Google Scholar 

  27. Segui-Simarro, J. M., Otegui, M. S., Austin, J. R., II & Staehelin, L. A. in Plant Cell Monographs Vol. 9 (eds Hong, Z. & Verma, D. P. S.) 251–287 (Springer, Berlin, 2008).

  28. Otegui, M. S., Mastronarde, D. N., Kang, B. H., Bednarek, S. Y. & Staehelin, L. A. Three-dimensional analysis of syncytial-type cell plates during endosperm cellularization visualized by high resolution electron tomography. Plant Cell 13, 2033–2051 (2001).

    Article  CAS  Google Scholar 

  29. Nicolas, W. J. et al. Architecture and permeability of post-cytokinesis plasmodesmata lacking cytoplasmic sleeves. Nat. Plants 3, 17082 (2017).

    Article  CAS  Google Scholar 

  30. Roth, R. et al. Nat. Plants (2019).

  31. Toth, R. & Miller, R. M. Dynamics of arbuscule development and degeneration in a Zea mays mycorrhiza. Am. J. Bot. 71, 449–460 (1984).

    Article  Google Scholar 

  32. Ivanov, S. & Harrison, M. J. A set of fluorescent protein-based markers expressed from constitutive and arbuscular mycorrhiza-inducible promoters to label organelles, membranes and cytoskeletal elements in Medicago truncatula. Plant J. 80, 1151–1163 (2014).

    Article  CAS  Google Scholar 

  33. Harrison, M. J., Dewbre, G. R. & Liu, J. A phosphate transporter from Medicago truncatula involved in the acquisition of phosphate released by arbuscular mycorrhizal fungi. Plant Cell 14, 2413–2429 (2002).

    Article  CAS  Google Scholar 

  34. de Boer, P., Hoogenboom, J. P. & Giepmans, B. N. G. Correlated light and electron microscopy: ultrastructure lights up! Nat. Methods 12, 503–513 (2015).

    Article  Google Scholar 

  35. Kellenberger, E. in Cryotechniquesin Biological Electron Microscopy (eds Steinbrecht, R. A. & Zierold, K.) 149–172 (Springer, Berlin, 1987).

  36. Gilkey, J. C. & Staehelin, A. L. Advances in ultrarapid freezing for the preservation of cellular ultrastructure. J. Electron Microsc. Tech. 3, 177–210 (1986).

    Article  Google Scholar 

  37. Alexander, T., Toth, R., Meier, R. & Weber, H. C. Dynamics of arbuscule development and degeneration in onion, bean, and tomato with reference to vesicular–arbuscular mycorrhizae in grasses. Can. J. Bot. 67, 2505–2513 (1989).

    Article  Google Scholar 

  38. Genre, A., Chabaud, M., Timmers, T., Bonfante, P. & Barker, D. G. Arbuscular mycorrhizal fungi elicit a novel intracellular apparatus in Medicago truncatula root epidermal cells before infection. Plant Cell 17, 3489–3499 (2005).

    Article  CAS  Google Scholar 

  39. Samuels, A. L., Giddings, T. H. & Staehelin, L. A. Cytokinesis in tobacco BY-2 and root-tip cells—a new model of cell plate formation in higher plants. J. Cell Biol. 130, 1345–1357 (1995).

    Article  CAS  Google Scholar 

  40. Drakakaki, G. Polysaccharide deposition during cytokinesis: challenges and future perspectives. Plant Sci. 236, 177–184 (2015).

    Article  CAS  Google Scholar 

  41. Wolf, J. M. & Casadevall, A. Challenges posed by extracellular vesicles from eukaryotic microbes. Curr. Opin. Microbiol. 22, 73–78 (2014).

    Article  CAS  Google Scholar 

  42. Cai, Q. et al. Plants send small RNAs in extracellular vesicles to fungal pathogen to silence virulence genes. Science 360, 1126–1129 (2018).

    Article  CAS  Google Scholar 

  43. Lo Presti, L. & Kahmann, R. How filamentous plant pathogen effectors are translocated to host cells. Curr. Opin. Plant Biol. 38, 19–24 (2017).

    Article  CAS  Google Scholar 

  44. Rutter, B. D. & Innes, R. W. Extracellular vesicles isolated from the leaf apoplast carry stress-response proteins. Plant Physiol. 173, 728–741 (2017).

    Article  CAS  Google Scholar 

  45. Hansen, G. H., Niels-Christiansen, L. L., Immerdal, L. & Danielsen, E. M. Scavenger receptor class B type I (SR-BI) in pig enterocytes: trafficking from the brush border to lipid droplets during fat absorption. Gut 52, 1424–1431 (2003).

    Article  CAS  Google Scholar 

  46. Crawley, S. W., Mooseker, M. S. & Tyska, M. J. Shaping the intestinal brush border. Journal of Cell Biology 207, 441–451 (2014).

    Article  CAS  Google Scholar 

  47. Sauvanet, C., Wayt, J., Pelaseyed, T. & Bretscher, A. in Annual Review of Cell and Developmental Biology Vol. 31 (ed. Schekman, R.) 593–621 (Annual Reviews, Palo Alto, 2015).

  48. Fok, A. K. et al. The vacuolar-ATPase of Paramecium multimicronucleatum: gene structure of the B subunit and the dynamics of the V-ATPase-rich osmoregulatory membranes. J. Eukaryot. Microbiol. 49, 185–196 (2002).

    Article  CAS  Google Scholar 

  49. Bartnicki-Garcia, S., Bracker, C. E., Gierz, G., Lopez-Franco, R. & Lu, H. S. Mapping the growth of fungal hyphae: orthogonal cell wall expansion during tip growth and the role of turgor. Biophys. J. 79, 2382–2390 (2000).

    Article  CAS  Google Scholar 

  50. Tayagui, A., Sun, Y. L., Collings, D. A., Garrill, A. & Nock, V. An elastomeric micropillar platform for the study of protrusive forces in hyphal invasion. Lab. Chip. 17, 3643–3653 (2017).

    Article  CAS  Google Scholar 

  51. Boisson-Dernier, A. et al. Agrobacterium rhizogenes-transformed roots of Medicago truncatula for the study of nitrogen-fixing and endomycorrhizal symbiotic associations. Mol. Plant-Microbe Interact. 14, 695–700 (2001).

    Article  CAS  Google Scholar 

  52. Hong, J. J. et al. Diversity of morphology and function in arbuscular mycorrhizal symbioses in Brachypodium distachyon. Planta 236, 851–865 (2012).

    Article  CAS  Google Scholar 

  53. Austin, J. R. in Arabidopsis Protocols Vol. 1062 (eds Sanchez-Serrano, J. & Salinas, J.) 473–486 (Humana Press, Totowa, 2015).

  54. Hickey, W. J., Shetty, A. R., Massey, R. J., Toso, D. B. & Austin, J. Three-dimensional bright-field scanning transmission electron microscopy elucidate novel nanostructure in microbial biofilms. J. Microsc. 265, 3–10 (2017).

    Article  CAS  Google Scholar 

  55. Ladinsky, M. S., Mastronarde, D. N., McIntosh, J. R., Howell, K. E. & Staehelin, L. A. Golgi structure in three dimensions: functional insights from the normal rat kidney cell. J. Cell Biol. 144, 1135–1149 (1999).

    Article  CAS  Google Scholar 

  56. Kremer, J. R., Mastronarde, D. N. & McIntosh, J. R. Computer visualization of three-dimensional image data using IMOD. J. Struct. Biol. 116, 71–76 (1996).

    Article  CAS  Google Scholar 

  57. Pumplin, N. & Harrison, M. J. Live-cell imaging reveals periarbuscular membrane domains and organelle location in Medicago truncatula roots during arbuscular mycorrhizal symbiosis. Plant Physiol. 151, 809–819 (2009).

    Article  CAS  Google Scholar 

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Financial support for this project was provided by the U.S. National Science Foundation grant no. IOS-1353367 and by the TRIAD Foundation. Confocal microscopy was carried out in the BTI Plant Cell Imaging Center (NSF DBI-0618969). Electron microscopy was carried out in the Imaging and Microscopy Facility at the Danforth Plant Science Center and at the Cornell Center for Materials Research Shared Facilities (the latter is supported through the NSF MRSEC program (DMR-1719875)). Electron microscopy for 3D electron tomography was undertaken at the Advanced Electron Microscopy facility at The University of Chicago.

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Authors and Affiliations



All authors conceived the experiments and analysed data; S.I., R.H.B. and J.A. carried out experiments; all authors wrote the manuscript.

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Correspondence to Maria J. Harrison.

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Journal peer review information: Nature Plants thanks Andrea Genre, Roger Innes, Erik Limpens and other anonymous reviewers for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figures 1–7, Supplementary Video Legends, Supplementary Methods and Supplementary Table 1.

Reporting Summary

Supplementary Video 1

Tomogram used for all modelling except in Fig. 2d,e. This slice movie through a 1-μm-thick section was made using 10-slice projections. The tomogram contains a total cellular volume of 10.14 μm3.

Supplementary Video 2

Tomogram used for modelling in Fig. 2d,e. The slice movie through a 1-μm-thick section was made using 10-slice projections and the part showing the features modelled in Fig. 2d,e is shown here.

Supplementary Video 3

Model of all components shown in Fig. 2 (except Fig. 2d,e) and Fig. 5.

Supplementary Video 4

IMC-I (with pores) and IMC-II (related to Fig. 2a).

Supplementary Video 5

ER remnants in the lumen of IMC-I (related to Fig. 2a).

Supplementary Video 6

Model of ER that has entered IMC-I (related to Fig. 2d,e).

Supplementary Video 7

Enclosure of fungal protoplast and tubules by the fungal cell wall (related to Fig. 5).

Supplementary Video 8

Top view of fungal tubules and protoplasts (related to Fig. 5).

Supplementary Video 9

Side view of fungal tubules and protoplasts (related to Fig. 5).

Supplementary Video 10

Proximity of the fungal tubules and plant intramatrix membrane systems (related to Fig. 2a and Fig. 5).

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Ivanov, S., Austin, J., Berg, R.H. et al. Extensive membrane systems at the host–arbuscular mycorrhizal fungus interface. Nature Plants 5, 194–203 (2019).

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