Morphological changes and bioaccumulation in response to cadmium exposure in , a fungus with potential for detoxification.

is a genus of edible fungi with strong resistance to cadmium (Cd) and the ability to accumulate it in its mycelia. However, the mechanisms underlying Cd resistance in remain unknown. In the present study, morphological and physiological responses to Cd were evaluated in the mycelia of . Variations in hyphal micromorphology, including twisting, folding, and kinking, in mycelia exposed to different Cd concentrations (0.15, 0.9, 1.5, 2.4, 5.0 mg/L) were observed using scanning electron microscopy. Deposition of Cd precipitates on cell surfaces (at Cd concentrations >2.4 mg/L) was shown by SEM-EDS. Transmission electron microscopy analysis of cells exposed to different concentrations of Cd revealed the loss of intracellular structures and the localization of Cd depositions inside and outside the cell. FTIR analysis showed that functional groups such as C=O, -OH, -NH, and -CH could be responsible for Cd binding on the cell surface of . In addition, intracellular accumulation was observed in cultures at low Cd concentrations (<0.9 mg/L), while extracellular adsorption occurred at higher concentrations. These results provide valuable information on the Cd tolerance mechanism in and provide a robust foundation for further studies on fungal bioremediation strategies.