ESPCI web site
Network of mycorrhizal filaments
Mycorrhizal fungi build intricate underground networks to exchange nutrients with plants and store carbon in the soil. Published in Nature on February 26, 2025, a study conducted by 28 researchers from around the world, including scientists from the Physique et Mécanique des Milieux Hétérogènes (PMMH) Laboratory at ESPCI Paris - PSL, reveals how these networks function as sophisticated supply chains, forming one of the most widespread symbiotic partnership in nature, forming in the roots of around 70% of plant species on Earth.
Mycorrhizal fungi rely on carbon provided by the host plant with which they form a symbiotic relationship. By colonizing plant roots, they receive the carbon necessary for their development in exchange for nutrients that support plant growth. This partnership requires managing significant constraints: balancing the construction costs of the mycorrhizal network as it expands while ensuring the efficient transport of resources over long distances toward and away from host roots.
For the first time, researchers visualized and quantified the growth of mycorrhizal networks using a specially designed imaging robot. This tool enabled them to simultaneously track over 500,000 fungal nodes—points where mycelial filaments intersect and interact—and analyze approximately 100,000 cytoplasmic flow trajectories, revealing the internal movement of nutrients and carbon within the network.
Unlike many biological organisms whose growth remains exponential as long as resources are available, the studied mycorrhizal fungi adopt a remarkably different strategy: they self-regulate their growth. After the passage of a propagating front, the fungal network reaches a density limit that is independent of resource availability. Instead of continuously expanding, the fungi redirect the carbon obtained from the plant toward exploring new areas. This means that rather than maximizing immediate growth, they optimize their spatial expansion, which in turn enhances their long-term ability to exchange and capture carbon.
Additionally, the study measured the growth rate of the mycorrhizal network, which remains constant over time. This indicates the fungi’s need to maintain efficient resource transport within the network. By analyzing cytoplasmic flows inside the mycorrhizal fungi, researchers observed a continuous bidirectional transport between the fungi and plant roots—evidence of the active exchange that sustains this symbiotic relationship. The organization of these flows follows principles comparable to a highly sophisticated and highly efficient logistical supply chain, shaped by hundreds of millions of years of natural selection.
These networks play a crucial role as entry points for carbon into global soils, absorbing approximately 13 billion tons of CO₂ each year—equivalent to one-third of global energy-related emissions. Despite their significance, the complexity and vast reach of these fungal networks had remained poorly understood. This study provides a detailed look at how mycorrhizal fungi construct and optimize their networks to ensure efficient nutrient exchange, ultimately influencing ecosystem function and global carbon cycles.
The discovery of these underground engineering mechanisms sheds new light on the complexity and ingenuity of the interactions that shape ecosystems. Understanding how these fungal networks organize, evolve, and optimize resource exchange allows us to further explore the incredible intelligence of living systems and the fundamental role of unseen organisms in structuring the natural world. These findings also offer new insights into the carbon dynamics in soil, a critical factor in the face of current environmental changes. By unveiling these natural strategies for carbon transport and storage, this research paves the way for rethinking how we integrate these underground networks into soil and ecosystem management in the future.
Collaboration : The work has been done in collaboration with other international research institutions, such as the team of Toby Kiers and Tom Shimizu (VU & AMOLF, Amsterdam, NL) and the team of Howard Stone (Princeton University, NJ, USA)..
Pictures and Video Credits : Loreto Oyarte Galvez (AMOLF & VU, Amsterdam)
–
References :
Oyarte Galvez, L., Bisot, C., Bourrianne, P. et al. A travelling-wave strategy for plant–fungal trade. Nature 639, 172–180 (2025). https://doi.org/10.1038/s41586-025-08614-x
NY Times papre : https://www.nytimes.com/2025/03/01/science/climate-mycorrhizal-fungus-networks.html
–
Contact :
Philippe Bourrianne (PMMH, ESPCI Paris) : 