How plant–fungus symbioses can support sustainable farming
Arbuscular mycorrhizal fungi (AMF) are beneficial soil fungi. They naturally associate with the roots of most crops, improving their acquisition of nutrients such as phosphorus and nitrogen. “These fungi can help crops become more resilient and reduce dependence on synthetic fertilisers,” explains MycUpscaling(opens in new window) project coordinator Stéphane Declerck from UCLouvain(opens in new window) in Belgium. “However, their use in agriculture remains limited because AMF are difficult to produce at scale. They depend on living plants and are therefore mostly produced in soil-based systems in greenhouses.” This is space-demanding and prone to contamination. While in vitro systems are promising alternatives, they tend to be costly and often produce lower spore yields.
Transforming roots into biological factories
The MycUpscaling project, supported by the Marie Skłodowska-Curie Actions(opens in new window) programme, set out to find better ways of mass-producing high-quality, contaminant-free AMF inoculum more efficiently. For this, the project brought together complementary expertise from Washington State University and UCLouvain. The proposed solution was to develop a new in vitro production platform in which the host plant root is engineered to better feed and support AMF growth. “The idea was to increase lipid biosynthesis in the root, promote lipid transfer to AMF, and favour the formation of lipid-rich fungal spores,” says Declerck. “In practice this meant transforming root organ cultures into more efficient biological factories for AMF inoculum production.” Engineered roots were tested for AMF colonisation, spore production, lipid accumulation and metabolic flux. Best-performing lines were further assessed for spore production dynamics, spore morphology and network architecture.
Enhancing plant lipid metabolism
The project produced several key advances. First, it generated and validated a broad molecular toolkit for engineering plant lipid metabolism. This included 116 genetic constructs and several engineered root lines designed to modify lipid biosynthesis, transfer and transport. Second, the project identified engineered root lines that significantly increased AMF spore production and demonstrated that host lipid engineering can improve symbiotic performance. The project generated proof of concept data directly linked to upscaling potential. “In particular, one selected engineered line reached a 6.55-fold increase in the area index and a 9.6-fold increase in the volume index compared with the control,” adds Declerck. “This indicates that the engineered system improved both spore abundance and spore-size-related inoculum biomass proxies.”
Strengthening crop resilience and soil health
This work will now be continued through the EU-funded AMFactory project, launched in May 2026. Next steps include reproducing and expanding on MycUpscaling’s results, bringing promising engineered systems up to the scale of bioreactor-oriented set-ups. This will enable assessments of production costs, reproducibility and industrial feasibility. “The long-term benefit of all this work is to make AMF-based bio-fertilisers more reliable, scalable and affordable for agriculture,” notes Declerck. “If successful, this technology could help farmers reduce dependence on chemical fertilisers, improve nutrient-use efficiency, strengthen crop resilience to drought and other stresses, and support more sustainable farming systems and soil health.” This aligns directly with the objectives of the European Green Deal(opens in new window) and farm to fork strategy(opens in new window) by offering a biological route to reduce environmental impact while maintaining crop productivity. “More broadly, MycUpscaling has shown the potential of turning plant–fungus symbioses into beneficial living production systems,” adds Declerck.
