According to THE GUARDIAN
Inside a large greenhouse at the University of Kansas, rows of sudan grass grow in individual plastic pots under carefully controlled conditions. Beneath the soil surface, the roots of each plant host a distinct strain of arbuscular mycorrhizal fungi—microscopic organisms that play an outsized role in sustaining life on land. Nearby, shelves in a cold-storage room hold thousands of vials and sealed bags containing fungal spores, meticulously preserved and catalogued.
Source: Wikimedia Commons, CC BY-SA 4.0
Together, these materials form the International Collection of Vesicular Arbuscular Mycorrhizal Fungi (INVAM), the world’s largest living repository of arbuscular mycorrhizal fungi. Built over four decades, the collection contains living spores from more than 900 distinct fungal strains gathered from six continents. Now, due to the loss of federal funding, this globally significant scientific resource may be forced to close within a year.
Researchers warn that the potential loss of INVAM would have far-reaching consequences, not only for fungal science but also for ecosystem restoration, sustainable agriculture, and climate resilience.
A Living Library of Underground Ecosystems
Arbuscular mycorrhizal fungi are among the most ancient and widespread symbiotic organisms on Earth. They form intimate relationships with approximately 70 percent of land plant species, spanning forests, grasslands, croplands, and natural ecosystems. In exchange for sugars and lipids from plants, these fungi supply essential nutrients such as phosphorus, nitrogen, and trace metals, while also improving water uptake and buffering plants against drought, disease, and other stresses.
Unlike seed banks or frozen genetic repositories, INVAM is a living collection. The fungal strains it preserves must be actively maintained, propagated, and renewed each year. Without continuous care, the spores die. This makes the collection uniquely valuable—and uniquely vulnerable.
Scientists describe INVAM as a “living library” because each fungal strain represents millions of years of evolutionary adaptation. Collectively, the library preserves biological knowledge that cannot be reconstructed once lost.
Source: Wikimedia Commons, CC BY-SA 4.0
Unlike seed banks or frozen genetic repositories, INVAM is a living collection. The fungal strains it preserves must be actively maintained, propagated, and renewed each year. Without continuous care, the spores die. This makes the collection uniquely valuable—and uniquely vulnerable.
Scientists describe INVAM as a “living library” because each fungal strain represents millions of years of evolutionary adaptation. Collectively, the library preserves biological knowledge that cannot be reconstructed once lost.
The Threat of Defunding
INVAM was established in 1985 and has relied on continuous federal support since its inception. Its most recent funding from the National Science Foundation (NSF) ended in May 2025. While curators are preparing new grant proposals, the funding environment has become increasingly uncertain.
Why INVAM Cannot Simply Be Replaced
Maintaining arbuscular mycorrhizal fungi requires specialized expertise and labor-intensive processes that exist in very few laboratories worldwide. Unlike many fungi, these organisms do not grow independently on artificial media. They must be cultivated in association with living host plants.
At INVAM, technicians isolate spores from field soils under a microscope, identify them based on subtle morphological features, and manually inoculate them onto the roots of sterile seedlings. The plants are then grown in controlled greenhouse conditions for weeks, after which water stress is applied to stimulate spore production. Each strain must undergo this process annually to remain viable.
Researchers emphasize that this knowledge represents an “arcane skillset” built through decades of experience. Losing INVAM would mean losing not only the fungal strains themselves, but also the institutional expertise required to work with them.
Scientific and Practical Importance
The importance of arbuscular mycorrhizal fungi extends well beyond academic research. These fungi play a central role in:
- ecosystem restoration, helping degraded landscapes recover biodiversity and soil function
- soil health, improving aggregation, water retention, and nutrient cycling
- carbon storage, acting as a major underground sink for carbon dioxide
- sustainable agriculture, reducing dependence on synthetic fertilizers
Field experiments conducted with fungi sourced from INVAM have demonstrated dramatic ecological effects. In prairie restoration projects, soils inoculated with native mycorrhizal fungi supported greater plant diversity, faster establishment, and long-term ecosystem stability compared with control plots lacking fungal inoculation.
These results underscore why many ecologists view arbuscular mycorrhizal fungi as vital ecosystem engineers.
Modern Agriculture and Fungal Loss
Despite their importance, arbuscular mycorrhizal fungi are often absent or severely depleted in intensively farmed soils. Practices such as deep tillage, excessive fertilizer application, and fungicide use disrupt fungal networks and reduce fungal diversity.
Studies show that in some long-cultivated soils, traces of arbuscular mycorrhizal fungi are barely detectable. Because these fungi disperse slowly and do not produce airborne spores, recolonization can take decades without human intervention.
This reality has driven interest in fungal inoculation as a tool for soil restoration and regenerative agriculture. However, researchers caution that the quality of commercial fungal products varies widely.
Source: Wikimedia Commons, CC BY-SA 4.0
The Biofertilizer Problem
INVAM also plays a critical role in evaluating and validating fungal biofertilizers. Independent studies have shown that a large proportion of commercial products marketed as mycorrhizal inoculants fail to colonize plant roots effectively. Some contain only dead spores, while others include unintended contaminants, including plant pathogens.
Despite these shortcomings, the global fungal biofertilizer market is valued at more than USD 1 billion annually. Researchers argue that the absence of strong regulation and the loss of public research infrastructure have allowed ineffective products to proliferate.
INVAM does not operate as a commercial producer. Instead, it provides verified, high-quality fungal material for research and restoration, serving as a benchmark for what functional mycorrhizal inocula should look like.
Climate Change and the Need for Fungal Diversity
As climate change alters rainfall patterns, temperature regimes, and soil conditions, the adaptive capacity stored within fungal diversity becomes increasingly important. Different arbuscular mycorrhizal strains confer different benefits to plants, from drought tolerance to nutrient efficiency.
Maintaining a broad library of fungal strains allows researchers to identify which symbioses are most effective under specific environmental stresses. The loss of such a library would limit the ability to respond to future ecological challenges.
Scientists emphasize that while plants can be reseeded and landscapes replanted, the loss of fungal diversity is far more difficult—often impossible—to reverse.
Source: Wikimedia Commons, CC BY-SA 4.0
Broader Implications for Public Science
The potential closure of INVAM highlights a broader issue facing publicly funded science: the vulnerability of long-term infrastructure to short-term budget decisions. Living collections, unlike individual research projects, require sustained investment to retain their value.
Researchers note that private donors may support targeted projects, but rarely provide the stable, multi-decade funding required to maintain foundational scientific resources. As a result, federally supported collections remain irreplaceable pillars of basic research.
The loss of INVAM would therefore represent not only a scientific setback, but also a structural weakening of global research capacity in fungal biology and soil ecology.
What Is at Stake
If INVAM closes, hundreds of unique fungal strains may be lost permanently. Along with them would disappear opportunities to:
- restore degraded ecosystems more effectively
- reduce fertilizer use and agricultural pollution
- improve climate resilience in crops and natural systems
- answer fundamental biological questions about fungal evolution and symbiosis
Scientists stress that arbuscular mycorrhizal fungi remain poorly understood, and many of their most intriguing biological traits—such as their unusual cellular organization and ability to form hybrids—can only be studied using living cultures.
References
INVAM – International Collection of Vesicular Arbuscular Mycorrhizal Fungi
FAO – Mycorrhizal Fungi and Soil Biodiversity
NSF – Budget and Funding Overview
According to THE GUARDIAN
Key Takeaways
- Proposed cuts to research funding are threatening the BEG (Biological Environment and Genomics) programme that maintains the world’s largest living reference collection of arbuscular mycorrhizal fungi (AMF), which supports agriculture, ecology, and climate science globally.
- Arbuscular mycorrhizal fungi cannot be cultured without a living plant host—unlike bacteria or yeast—making living reference collections uniquely difficult and costly to maintain but irreplaceable once lost.
- AMF form symbiotic relationships with approximately 72% of all vascular plant species, including most agricultural crops; they are fundamental to soil carbon storage, phosphorus cycling, and drought tolerance.
- Loss of the AMF reference collection would directly impair agricultural research aimed at reducing chemical fertiliser use—one of the primary levers for sustainable food system transformation.
- Scientific collections including fungal culture libraries represent accumulated knowledge capital that, once lost, may take decades or centuries to partially reconstruct—if reconstruction is possible at all.
Frequently Asked Questions
What is an arbuscular mycorrhizal fungi culture collection and why is it important?
Arbuscular mycorrhizal fungi (AMF) culture collections are living repositories of authenticated, characterised AMF strains maintained in ongoing plant host cultures. Because AMF are obligate biotrophs—they cannot complete their life cycle without a living plant host—they cannot be preserved in liquid nitrogen or freeze-dried like bacteria. Living collections require continuous cultivation in sterile plant culture systems, genetic archiving, physical space, and trained personnel. These collections provide reference material for taxonomy (confirming species identity), agricultural research (testing specific strains for crop performance), ecological research (tracking genetic diversity across habitats), and commercial inoculant development.
How do arbuscular mycorrhizal fungi help crops?
AMF colonise the roots of approximately 72% of vascular plant species and form a mutualistic symbiosis in which the fungus provides the plant with phosphorus, zinc, and other micronutrients in exchange for plant-derived sugars. This relationship provides multiple agricultural benefits: AMF colonisation can reduce the need for phosphate fertiliser by 25–50%; improve plant drought tolerance by extending effective root water-uptake range; enhance resistance to some root pathogens; improve soil structure through production of glomalin (a glycoprotein that aggregates soil particles); and facilitate plant establishment in disturbed or low-nutrient soils. AMF inoculants are used commercially in organic agriculture and agroforestry.
Why are AMF so difficult to preserve in culture collections?
Unlike free-living fungi (such as Aspergillus or Penicillium species) that can be grown on artificial media, AMF are obligate biotrophs—they require a living plant host to grow and reproduce. This means maintaining a collection of 100 AMF strains requires running 100 separate plant culture systems continuously, each consisting of sterilised growth medium, a host plant, and the AMF strain. These must be regularly subcultured, quality-checked for contamination, genotyped to confirm strain identity, and maintained at appropriate temperatures. The recurring cost of personnel, space, consumables, and plant host maintenance makes living AMF collections several times more expensive to maintain per strain than bacterial or free-living fungal collections.
What happens if we lose access to AMF reference collections?
Loss of reference AMF collections would have several cascading consequences. Taxonomic research would lose verified type specimens and authenticated comparison strains, making it impossible to confirm species identifications in new research. Agricultural research programmes that have spent decades characterising the performance of specific AMF strains would lose their biological materials, potentially abandoning work that cannot be replicated. Commercial inoculant producers who rely on authenticated starting strains for quality-controlled products would face supply chain disruptions. Globally, losing genetic diversity in culture collections may mean losing strains with unique properties for specific crops, soils, or climate conditions—irreplaceable resources for future agricultural adaptation.
How much of the soil carbon cycle depends on mycorrhizal fungi?
Mycorrhizal networks—including both arbuscular (AMF) and ectomycorrhizal fungi—are estimated to be responsible for approximately 5 billion tonnes of carbon sequestration annually, equivalent to about 13% of global atmospheric CO₂ absorption. They achieve this through three mechanisms: glomalin production by AMF (a highly stable soil protein that can persist for 7–42 years); hyphal networks that physically stabilise soil aggregates and protect organic matter from decomposition; and facilitation of plant growth on marginal soils, extending the land area covered by carbon-fixing vegetation. A 2023 Nature Communications study estimated that mycorrhizal fungi-mediated carbon storage is equivalent to annual emissions from China. Defunding the science that supports this ecosystem service is, in this sense, a climate issue.
