Fungi play an indispensable ecological role by decomposing organic matter and recycling nutrients essential for life. However, beyond their environmental impact, these organisms harbor untapped potential in the realm of advanced materials. The University of Utah’s mechanical engineering team, led by Ph.D. candidate Atul Agrawal and Professor Steven Naleway, has revealed that M. marquandii can be cultivated into multilayered hydrogels—soft, water-saturated networks that closely mimic the mechanical characteristics of living tissues.

Hydrogels are paramount in biomedical engineering because of their ability to retain substantial amounts of water while maintaining structural integrity and flexibility. Traditional artificial hydrogels often fall short due to limitations in durability and biocompatibility. In contrast, the living hydrogels derived from M. marquandii display a unique combination of elasticity, resilience, and hierarchical architecture, making them outstanding candidates for scaffolding materials that foster cell growth and tissue regeneration.

Unlike many fungi that struggle with water retention, M. marquandii hydrogels absorb up to 83% water by volume and demonstrate remarkable ability to recover their shape following mechanical deformation. This elasticity owes much to the fungus’s complex, layered construction, where alternating zones of varying porosity—ranging from 40% to 90%—create a functionally graded structure. Such spatial variations in microarchitecture are critical for distributing mechanical stress, ultimately enhancing the hydrogel’s performance under dynamic physiological conditions.

This discovery was serendipitously made during research initially aimed at studying a hydrocarbon-degrading fungus, colloquially known as “kerosene fungus,” infamous for contaminating aviation fuel. Contrary to expectations, the cultures exhibited unanticipated growth patterns, prompting detailed investigation and correct identification of the organism as Marquandomyces marquandii. This exemplifies the unpredictable yet rewarding nature of mycological research, where misidentifications often lead to novel breakthroughs.

The structural backbone of fungal mycelium chiefly comprises chitin, a biopolymer also found in crustacean shells and insect exoskeletons. The biocompatibility and spongy texture of chitin-rich mycelium present enormous advantages for biomedical use, including ease of integration with human tissues and a reduced risk of inflammatory reactions. Furthermore, the living nature of these hydrogels offers dynamic capabilities, such as self-healing and adaptability under stress—features typically absent in synthetic materials.

In collaboration with mycologist Bryn Dentinger, the team sheds light on why fungal mycelia’s mechanical properties are particularly interesting. The fungi grow by extending hyphae—filamentous threads—that continuously compartmentalize into individual cells separated by cross-walls. This mode of indefinite linear growth without a defined developmental endpoint is distinct from the cellular differentiation found in animals and plants. Every fungal cell remains pluripotent, able to revert and adapt, offering an unparalleled level of malleability and structural complexity advantageous for engineered living materials.

Laboratory assessments employed sophisticated mechanical testing instruments to quantify tensile strength, shear response, and compressive behavior of the mycelium-based hydrogels. The material’s ability to regain 93% of its original shape after stress and maintain cohesive integrity due to a connected mycelial network showcases the intrinsic synergy of biological design and mechanical functionality. Such qualities indicate potential for creating flexible biomedical devices that endure repetitive movements, such as wearable sensors or implantable scaffolds.

An intriguing feature of these living hydrogels is their multilayered design, which deviates from uniform synthetic gels. Optical imaging revealed alternating layers of differing porosities within the fungal colony, a functionally graded architecture that not only distributes mechanical stress more evenly but could also support spatially controlled cellular environments. This property could be harnessed to engineer tissues with region-specific characteristics, closely mimicking natural organ complexity.

The implications of these findings extend beyond biomedicine. The exceptional strength-to-weight ratios inherent to mycelium structures, as outlined in prior research from the Utah team, suggest applications in aerospace and agriculture, where lightweight, sustainable materials are in high demand. The ability to mineralize fungal scaffolds, transforming them into bone-like substrates, hints at a versatile platform technology adaptable to various industrial needs.

Funding from the U.S. National Science Foundation and the American Chemical Society has underpinned the rigorous experimental studies culminating in this breakthrough. The published findings, appearing in the journal JOM, offer comprehensive data on the fabrication, characterization, and mechanical analysis of these fungal hydrogels, marking a pivotal moment in the burgeoning field of bioinspired materials science.

What started as an exploratory path into environmental microbiology has now evolved into a promising frontier for living materials that blend form, function, and sustainability. As researchers continue to decode the complex biology of fungi and harness their intrinsic material capabilities, the future is bright for novel biomaterials that not only push the boundaries of technology but also respect and emulate nature’s designs.

Subject of Research: Not applicable

Article Title: Multilayer, Functionally Graded Organic Living Hydrogels Built by Pure Mycelium

News Publication Date: 27-Aug-2025

Web References:

• https://link.springer.com/article/10.1007/s11837-025-07685-5
• http://dx.doi.org/10.1007/s11837-025-07685-5

References:
Agrawal, A., Elnunu, I., Naleway, S., et al. (2025). Multilayer, Functionally Graded Organic Living Hydrogels Built by Pure Mycelium. JOM. https://doi.org/10.1007/s11837-025-07685-5

Image Credits: Brian Maffly, University of Utah

Keywords:
Materials engineering; Fungi; Mechanical properties; Mycology

Ectomycorrhizal fungi form symbiotic associations with roughly a quarter of all terrestrial vegetation worldwide, a partnership that fuels critical biochemical cycles. Their underground hyphal networks not only ferry essential nutrients like nitrogen and phosphorus to plants but also sequester vast amounts of carbon by transporting it into deep soil layers. Estimates suggest these fungi are responsible for the annual drawdown of more than nine billion tons of atmospheric CO₂, equating to over 25% of global fossil fuel emissions—a staggering ecosystem service that underscores their climate relevance. Despite this, our catalog of described fungal species remains woefully incomplete. Current estimates indicate only about 155,000 fungal species have been formally described, a fraction of the 2 to 3 million species believed to inhabit the Earth.

The primary obstacle to understanding this subterranean biodiversity lies in the prevalence of “dark taxa,” fungal groups identifiable only through sequences of environmental DNA (eDNA) extracted from soil and root samples. Modern sequencing technologies allow scientists to detect these DNA fragments shed by organisms into their surroundings, but the process of linking DNA sequences to known species depends on existing reference databases. Unfortunately, the majority of fungal eDNA sequences lack corresponding, named species in these databases. As a result, researchers encounter strings of nucleotides—As, Ts, Cs, and Gs—that betray an organism’s existence but provide no avenue for classical taxonomic classification.

Lead author Laura van Galen, a microbial ecologist associated with the Society for the Protection of Underground Networks (SPUN) and ETH University in Switzerland, captures the dilemma succinctly: “Environmental DNA has enormous potential as a research tool to detect fungal species, but we can’t include unnamed species in conservation initiatives. How can you protect something that hasn’t yet been named?” This paradox illuminates a critical gap in biodiversity protection—undocumented species that underpin fundamental ecosystem processes remain invisible to policymakers and conservation frameworks predicated on formal taxonomic recognition.

The biogeography of these dark taxa is equally revealing. The review identifies discrete global hotspots where unknown ectomycorrhizal species cluster, specifically tropical forests in Southeast Asia, Central and South America, as well as tropical shrublands in central Africa. Additional hotspots include the montane conifer forests of the Sayan Mountains above Mongolia and other understudied mid-latitude and southern-hemisphere regions. These findings disrupt the traditional ecological paradigm that has disproportionately focused on temperate northern ecosystems. There is an urgent need to redistribute scientific resources and funding to these biodiverse, yet neglected, regions where fungal diversity—and thus ecosystem resilience—may be most vulnerable.

The ramifications for conservation are profound. Many of the plants dependent on ectomycorrhizal fungi are themselves categorized as endangered, a sobering reminder of the interconnectedness of life. The potential loss of host plants inevitably jeopardizes their fungal partners, many of which are essential to soil health, nutrient cycling, and carbon sequestration. Van Galen warns, “If we lose these host plants, we might also be losing really important fungal communities that we don’t know anything about yet.” This cascade effect underscores the intrinsic value of fungi in maintaining biodiversity and ecosystem services.

Addressing this invisible fungal frontier requires innovative approaches. The researchers advocate for increased collection, morphological study, and genomic sequencing of mushrooms and fungal specimens. Co-author Camille Truong of SPUN and the Royal Botanic Gardens Victoria highlights a low-hanging fruit: “There are mushrooms that have been sitting for decades in collections of botanical gardens. These should be urgently sequenced so that we can, hopefully, start matching them up with some of these dark taxa.” This strategy offers a rapid, cost-effective pathway to expand fungal reference databases that can transform unidentified eDNA into named entities, a cornerstone for integrating fungi into conservation policies.

The technological tools underpinning this effort are mature and accessible. High-throughput DNA sequencing, advanced bioinformatics pipelines, and global data-sharing platforms provide an unprecedented capacity to profile soil fungal communities in situ. Yet, despite these advancements, fungi remain conspicuously overlooked in global conservation and climate agendas. The call to action is clear: elevate fungal biodiversity to the same level of importance as plants and animals in ecological research, environmental monitoring, and policy making.

SPUN’s mission exemplifies this paradigm shift. The non-profit scientific organization aims to map and safeguard Earth’s fungal networks in collaboration with local researchers and communities, focusing especially on regions harboring high concentrations of undocumented fungi. Through these partnerships, SPUN seeks to fill critical knowledge gaps and advocate for the inclusion of fungi in climate and conservation strategies worldwide. Their work highlights the ecological significance of subterranean biodiversity and the urgent need to protect these cryptic yet essential life forms.

In synthesizing this review’s insights, it becomes evident that naming and documenting fungal species is not merely a taxonomic exercise; it is foundational to preserving ecosystem functions that sustain human and planetary health. Without clear identification and understanding, conservation efforts risk overlooking key organisms that stabilize soils, promote plant growth, and mitigate climate change through carbon sequestration. The invisibility of dark taxa thus represents both a scientific frontier and a critical conservation blind spot demanding immediate attention.

The discovery of global hotspots teeming with undescribed ectomycorrhizal fungi also reframes our understanding of biodiversity patterns. Tropical forests and understudied montane regions emerge as reservoirs of fungal diversity that could harbor novel species, metabolic pathways, and ecological interactions. Unveiling these hidden communities could yield breakthroughs not only in ecology but also in biotechnology, medicine, and agriculture.

As the scientific community advances toward a more comprehensive catalog of Earth’s fungi, the review underscores a vital principle: conservation is necessarily tied to knowledge. Protecting fungi without their formal recognition is practically and legally challenging; thus, expanding the fungal species’ registry becomes an ethical imperative. Bridging the knowledge gap will require cross-disciplinary collaboration, enhanced funding, and inclusive capacity-building among scientists in the Global South, where fungal diversity is richest but research infrastructure often lags.

In conclusion, the review published in Current Biology charts a new trajectory for mycology and conservation science. It reveals that a vast majority of Earth’s ectomycorrhizal fungi remain hidden in the shadows of taxonomy, detected only through environmental DNA signatures without formal names or descriptions. This “dark taxa” phenomenon not only complicates biodiversity assessments but threatens to exclude fungi from much-needed conservation policies despite their ecological indispensability. Bringing these organisms into the light through strategic sequencing, taxonomy, and global collaboration is essential for safeguarding Earth’s climate, biodiversity, and the health of ecosystems that humanity depends upon.

Subject of Research: Not applicable

Article Title: The biogeography and conservation of Earth’s ‘dark’ ectomycorrhizal fungi

News Publication Date: 9-Jun-2025

Web References:
https://spun.earth/
http://dx.doi.org/10.1016/j.cub.2025.03.079

Image Credits: Adriana Corrales/SPUN

Keywords:
Mycorrhizal fungi, Mycology, Ecology, Applied ecology, Biodiversity, Conservation ecology