Plant preferential allocation and fungal reward decline with soil phosphorus: implications for mycorrhizal mutualism

By B. Ji, James D. Bever. 2016

109 citations recorded by the source corpus.

Explaining the persistence of mutualism remains a challenge in ecology and evolutionary biology. The evolutionary stability of arbuscular mycorrhiza, a most widespread and ancient mutualistic association, is particularly intriguing because plants lack apparent mechanisms to prevent cheaters from gaining competitive advantages over cooperators. We developed a triple isotopic labeling method (14C, 32P, and 33P) within a splitroot design to measure the exchange of carbon (C) and phosphorus (P) between the host plant and two mycorrhizal partners across a soil P gradient. Host plant preferentially allocated more C to the roots associated with the fungus delivering higher P per unit plant C, and the strength of preferential allocation decreased with increasing soil P availability. The host plant received more P per unit of allocated C from the better fungus and this advantageous exchange rate did not depend upon P availability. As a result, the level of preferential allocation was correlated with the differential delivery of P from the two fungi. Our findings suggest that plant preferential allocation to better mutualists can stabilize mutualisms in environments limiting in the traded resource, but as the availability of this resource increases, plant preferential allocation declines. This environmental dependence of preferential allocation generates predictions of declining levels in relative abundance of mutualistic fungi in highresource environments.

Subfields: Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation, Plant Science

View Paper: https://www.semanticscholar.org/paper/d813afe67c5fc27fc133371b523d3fb4dac80ed7

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In Ecology, Evolution, Behavior and Systematics

In Nature and Landscape Conservation

In Plant Science

Citations in the corpus

Mycorrhizal feedbacks generate positive frequency dependence accelerating grassland succession (2018, background): “…the proportion of beneficial fungi relative to nonbeneficial fungi, as might be expected from observations of preferential allocation to the most effective mutualist (Bever, Richardson, Lawrence, Holmes, & Watson, 2009, Kiers et al., 2011, Zheng, Ji, Zhang, Zhang, & Bever, 2015, Ji & Bever, 2016).”
Carbon flow from plant to arbuscular mycorrhizal fungi is reduced under phosphorus fertilization (2017, background): “Despite some experimental evidence that plants can preferentially supply C to those AMF that supply more P (Ji and Bever 2016; Kiers et al. 2011), there is, to the best of our knowledge, as yet no unequivocal experimental evidence that plants would specifically reduce C supply to AMF under elevated…”
Soil microbiome: a key player for conservation of soil health under changing climate (2019, background): “Evolutionary studies can foretell the strength of artificial microbes and microbial mutualisms over time (Bever 2015; Ji and Bever 2016).”