Free living amoebae and Fusarium oxysporum can be recovered in the same environment
and may potentially interact. The presence of these protozoa could lead to an increased
development of this filamentous fungus. To assess this potential risk, the interactions
between two free living amoebae, Acanthamoeba castellanii and Hartmanella vermiformis, and
F. oxysporum, which can be isolated from soil and water, were studied. After 48 hr of
coincubation in tap water, culturable fungi were quantified. In addition, the interactions
between the free living amoebae and the fungus were investigated using electron microscopy.
We show that the presence of amoeba trophozoites increased the growth of F.
oxysporum without fungal influence on amoebae viability. In the same way, incubation of
the fungus with culture supernatants of the two amoebae induced fungal germination and
increased fungal growth. The results of this study confirm that the presence of amoebae
should be taken into consideration in the different environments where they may be in
contact with Fusarium.