a b s t r a c t
Three antagonistic fungi (Trichoderma asperellum isolate T2, Diaporthe sp. isolate WAA02, Penicillium citrinum
isolate BTF08) were evaluated for their tolerance to metals and the impact of the metals on their
antifungal expression against a model pathogen (Ganoderma boninense). Experiments performed include
metal tolerance and dual culture assays, viability test, SEM and Pearson Correlation test. In the presence
of metals, growth and antifungal expression of the endophytes were inhibited, particularly by Cd2+
(50 ppm), Zn2+ (100 ppm), and Cu2+ (100 ppm). The antifungal expression was least affected by the presence
of Pb2+ (60–100% inhibition) but was 0% in Al3+, Cd2+, Cu2+ and Zn2+ (200 ppm onwards). The absence
of antifungal expression was associated with their poor growth in these metals (r = 0.6080–0.8911).
Clearly, the growth and antifungal activity of these isolates are influenced by the metal species and concentrations,
and is an important factor for future development of antagonistic fungi as biopesticides