The Plant-Fungal Marketplace

Plant-fungal symbiosis is stabilized by the extent of reciprocal nutrient supply. The transition of plants to land, 470 million years ago, relied on the emergence of cooperation between plants and soil microbes (1). Both fossil records and the conserved mechanism for fungal recognition among plants (2) support the ancestral nature of this relationship. Today, in over 80% of land plants, roots associate with the soil fungi Glomeromycetes, forming chimeric organs called mycorrhizae (3). Plants depend on Glomeromycetes for mineral resources, especially phosphorus, which is limiting in many soils. Reciprocally, Glomeromycetes depend on nutrients produced by plants during photosynthesis (see the figure). On page 880 of this issue, Kiers et al. (4) unravel mechanisms that stabilize this ancient symbiotic relationship.

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