A fungus binds iron and rewires its metabolism to withstand excess metal

Iron stays within the system

Mingzheng Duan and colleagues describe how strain LY9 of Leucocalocybe mongolica responds to excess iron in a paper published on 22 September 2026 in Communications Biology. The work brings together measurements of soil, the spatial distribution of elements, gene activity and metabolites. When checked, the publisher was providing the accepted paper ahead of its final edited version.

The central distinction is bioavailability: how much of an element is available to biological processes. The authors report that an amendment involving LY9 reduced iron availability in a dose-dependent manner. Their treatment labelled 50% produced a reported reduction of 28.3%. This does not mean that the same reduction would occur in any soil, or that 28.3% of all iron had vanished from the environment. Binding a metal and changing its availability are different from physically removing it from the experimental system.

Where the mycelium grows matters

Spatial analysis revealed differences across the colonised substrate. The researchers describe a 26.9% depletion of soluble iron in densely colonised zones. Mycelial growth therefore produced a local environment unlike less extensively colonised areas. This matters when evaluating a possible environmental treatment: a whole-sample average can conceal differences between material reached by hyphae and material beyond their immediate influence.

In another experiment, with an iron(II) concentration of 25 mg/l, LY9 tolerated the exposure and accumulated iron in its biomass. The reported peak was 41.23 mg/kg on day fifteen. These units describe iron in biomass; they are neither the concentration of the surrounding solution nor a percentage removal from an entire volume of soil. Keeping those measurements separate prevents a promising laboratory observation from becoming an exaggerated claim about cleanup performance.

Cellular protection has several components

The team also examined gene activity and metabolites at the fifteen-day point. The results indicate coordinated changes in antioxidant defence, energy metabolism and reinforcement of the cell wall. Glutathione and its precursor were among the compounds that accumulated. Comparing gene expression with metabolites connects the cell's regulatory response to the substances actually present, rather than treating a list of activated genes as the entire explanation.

The practical next step is to investigate LY9 further as a candidate for treating substrates affected by excessive iron. Fungal tolerance and lasting improvement of soil quality remain distinct outcomes. Field applications would require evidence about the stability of metal binding and what happens to the biomass after growth ends. The results also provide no basis for advice about eating fruit bodies: measuring metal handling in mycelium is not a food-safety assessment.

This is an original editorial explanation of Duan and colleagues' findings. The source paper is available under CC BY 4.0; its results have been condensed and explained here.