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Study

Reciprocal rewards stabilize cooperation in the mycorrhizal symbiosis

Kiers, E. T.; Duhamel, M.; Beesetty, Y.; Mensah, J. A.; Franken, O.; Verbruggen, E.; Fellbaum, C. R.; Kowalchuk, G. A.; Hart, M. M.; Bago, A.; Palmer, T. M.; West, S. A.; Vandenkoornhuyse, P.; Jansa, J.; Bücking, H.

Science, 2011

Peer-reviewedcontrolled laboratory experimentlaboratory

What they did

Roots were offered a choice of fungal partners, and fungi a choice of hosts, with the phosphorus supplied by each fungus and the carbon supplied by each plant tracked using stable isotopes. Some partners were experimentally made less generous than others.

Studied in
Medicago truncatula, Glomus intraradices, Daucus carota
Sample size
root-organ and whole-plant cultures with isotope labelling

What they found

Plants directed more carbon to the fungal partners that delivered more phosphorus, and fungi directed more phosphorus to the roots that supplied more carbon. Each side allocated preferentially to the better-performing partner, in both directions, within the same experiment.

What it means

The authors' reading, and ours. Where they differ, that difference is the point.

How the authors put it

Reciprocal reward — biological market behaviour on both sides — stabilises the mycorrhizal symbiosis against partners that take without giving.

How NatureHQ reads it

The best available evidence about what kind of relationship this is, and it is not the one in the popular version. Nothing here is generous. Both partners preferentially supply whoever is supplying them, which is a trading mechanism that keeps the relationship stable precisely because neither side can freeload. That is a more interesting fact than mutual aid, and it is the reason NatureHQ describes mycorrhizas as an exchange rather than as fungi feeding trees.

Limitations

  • Simplified laboratory systems, including root-organ cultures without a whole plant.
  • Arbuscular mycorrhizas; ectomycorrhizal partnerships, which dominate temperate forests, may differ.
  • Demonstrates preferential allocation, not the mechanism by which either partner senses the other.

The experiment, explained

  • Giving a root a choice of fungi, and a fungus a choice of roots

    Is the exchange between a plant and its fungus generosity, or is each side paying the better supplier?

What this study is used for on NatureHQ

One study can inform several subjects. Here is everywhere this one is cited.

Finding the paper

Published by: American Association for the Advancement of SciencePublished in Science or Science Advances (AAAS).

doi.org/10.1126/science.1208473

This reference was resolved automatically against Crossref on 2026-08-30.

NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-30.