Extracellular vesicles from Fusarium oxysporum can induce a cytotoxic response in an invertebrate model.

Aims: One of the ways fungi communicate is through extracellular vesicles (EVs), which vary in size and content depending on the species and fungal form. This study investigated the release of EVs from Fusarium oxysporum, noting significant differences in their structure and biological effects in both in vitro and in vivo.

Methods and results: The study found that the size of these vesicles was consistent with patterns observed in other fungal species. Notably, the release of EVs from the planktonic form increased exponentially after 120 h of growth, resulting in heightened vesicle production. In biofilm, EVs released from the biofilm matrix showed distinct characteristics from those secreted externally, with a peak in release at 24 h. The concentration of EVs inside the biofilm was significantly higher, reflecting the complexity of biofilm dynamics. Additionally, EVs from the biofilm, particularly those isolated at 48 h of maturation, were highly cytotoxic, causing over 95% cell death in human cells. In vivo experiments with Tenebrio molitor larvae showed that EVs from biofilms could induce significant mortality.

Conclusion: These findings suggest that EVs may serve as communicators and can also trigger pathogenic effects by transporting cytotoxic molecules.