Antifungal activity of Serratia marcescens CFFSUR-B2 purified chitinolytic enzymes and prodigiosin against Mycosphaerella fijiensis, causal agent of black Sigatoka in banana (Musa spp.)

The ascomycete fungus Mycosphaerella fijiensis causes black Sigatoka disease of banana. Because Serratia marcescens strain CFFSUR-B2 is an effective agent for the biological control of M. fijiensis, it was important to determine the mechanisms by which this bacterium stops or inhibits infection by this phytopathogen. The individual chitinases were effective in reducing germ tube growth to different degrees. We evaluated also the effect of mixtures of purified chitinases (ChiA, ChiB and ChiC) and prodigiosin on the germination and germ tube growth of M. fijiensis ascospores. None of the combinations inhibited ascospore germination. However, a toxic effect similar to that of benzimidazole was observed on ascospore germination by the synergistic action of chitinases and prodigiosin applied in combination. The maximal effect in inhibiting germ tube development observed with a mixture of the chitinases and prodigiosin suggests that these could be used in the effective biocontrol of black Sigatoka disease.