The dynamic roles of intracellular vacuoles in heavy metal detoxification by Rhodotorula mucilaginosa.

This article focuses on the physiological and transcriptomic responses of the fungus *Rhodotorula mucilaginosa* (Rho) under stress from heavy metals lead (Pb), cadmium (Cd), and copper (Cu). Using transmission electron microscopy and RNA sequencing, the study found that Rho employs distinct resistance mechanisms depending on the metal: vacuolar sequestration and activation of autophagy-related genes are critical for Pb tolerance, superoxide dismutase (SOD) plays a major role in Cd resistance, and efflux pumps along with divalent metal ion transporters reduce intracellular Cu levels. The research highlights that Pb stress induces vacuolar fusion and lipid degradation responses, while Cd interferes with vacuolar fusion due to competition with calcium ions, and Cu exhibits the highest toxicity linked to low cellular sorption. These findings provide genetic and morphological insights into fungal survival strategies against heavy metal toxicity.