image showing Mycorrhizas of false truffles (Elaphomyces spp.)
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Peeking into the black box: Discovering fungal diversity below ground

In a ground-breaking study, scientists have been able to uncover the diverse world of soil-dwelling ectomycorrhizal fungi across Europe. Discovering the influences of soil, climate, pollution and tree host has revealed some surprising results.
Date: 
6 June 2018
Blog team: 
Author: 
Laura Martinez-Suz, Sietse van der Linde & Martin I. Bidartondo

The importance of soil, and the organisms that live within it, has been known for many years. However, it has been impossible for scientists to disentangle this impenetrable black box due to the below ground growth of these organisms and technical difficulties. 


image showing Belowground fruitbodies of false truffles (Elaphomyces granulatus) (Image: Caroline Hobart

Belowground fruitbodies of false truffles (Elaphomyces granulatus) (Image: Caroline Hobart)


Now, for the first time, scientists from Kew and Imperial College, have been able to show the distribution, abundance and tree host preference of a major group of forest soil organisms, the ectomycorrhizal fungi across the whole of Europe. This research investigates how the diversity and distribution of ectomycorrhizal fungi is influenced by factors including soil factors, climate, air pollution and tree host characteristics (e.g. tree species and nutrient status).


image showing Mycorrhizas of false truffles (Elaphomyces spp.)

Mycorrhizas of false truffles (Elaphomyces spp.) (Image: RBG Kew/Laura Martinez-Suz)


Ectomycorrhizal fungi are a group of organisms that have developed a mutualistic way of life. Growing in between root cells and out of roots, they have been shown to both provide soil nutrients to trees as well as protect them from water shortages and disease, in exchange for carbohydrates from the trees. But understanding how the fungi themselves manage to survive, how many different species there are, and where they grow, has proved elusive. Previously, mushrooms appearing on the soil surface in autumn were the only way for mycologists to understand diversity and distribution, but we know that not all fungi reproduce above ground (e.g. truffles). Now, in collaboration with one of the largest environmental monitoring networks, ICP Forests, and with support from the UK Natural Environment Research Council, the team analysed 40,000 roots from 13,000 individual soil samples across European forests. Through the use of DNA technologies, the team worked to identify the fungi that were symbiotically associated with beech, spruce, pine and oak in 137 sites.


Image showing Oak forest site sampled for the mycorrhizal survey in this study. They belong to ICP Forests, a European network of monitored sites

Oak forest site sampled for the mycorrhizal survey in this study. They belong to ICP Forests, a European network of monitored sites (Image: RBG Kew/Laura Martinez-Suz)


Estimating fungal diversity across different tree species, and across different geographic zones across Europe, from southern Italy to northern Finland, and from Spain to Romania, scientists have for the first time, a better understanding of which mycorrhizal fungi grow where, and why. They have found that environment and tree characteristics can explain mycorrhizal diversity, that the pollution thresholds used as major ecosystem assessment tools need strong downward adjustment, and that mycorrhizal specificity and plasticity have been underestimated.


Image showing that Fine roots of the trees are covered by white fungal tissue forming ectomycorrhizas that sometimes can be seen with the naked eye

Fine roots of the trees are covered by white fungal tissue forming ectomycorrhizas that sometimes can be seen with the naked eye (Image: RBG Kew/Laura Martinez-Suz)


Understanding distributions of these plant‐symbiotic fungi is crucial for predicting soil and forest responses to environmental change. This type of information will help us, not only to protect this important group of fungi, but also the trees that depend on them to survive.

- Laura, Sietse & Martin - 

For further information read the research paper, published in Nature:

van der Linde, S. et al (including Suz, L.M & Bidartondo, M.I.) (2018). Environment and host as large-scale controls of ectomycorrhizal fungi. Nature. DOI:10.1038/s41586-018-0189-9. Available online


Find out more

Meet the author

Find out more about Laura's work here at Kew. 

Kew Science blog

Could fungi determine which plants survive and which don’t? Relationships between plants and fungi are important and more complex than previously thought, influencing the ability of ecosystems to adapt to impacts such as climate change.

Image showing Salix herbacea

Project

Plant-fungal interactions in Alpine ecosystems: Investigating fungal mycorrhizas and their plant hosts across elevational and latitudinal gradients in Alpine ecosystems: diversity, environmental drivers and threats.

The Swiss Alps