Screening of bacteria of the genus Bacillus for the control of the plant-pathogenic fungus Macrophomina phaseolina

This study evaluated the efficiency of 19 Bacillus isolates, obtained from the rhizosphere and rhizoplane of wild and cultivated castor bean plants, to control the pathogenic fungus Macrophomina phaseolina. Using in vitro assays, we examined the antifungal effects of volatile and non-volatile compounds, the production of siderophores and the activity of chitinase in these isolates. In vivo experiments were conducted to determine the potential of the Bacillus isolates to colonise castor bean plant roots and to control the fungus. In general, results showed that isolates from wild castor bean, compared with isolates from cultivated castor bean, were more efficient producers of antifungal compounds, better colonisers of plant roots and more effective protectors of plant seedlings against infection with M. phaseolina. Altogether, isolate RP 5, originating from the rhizoplane of wild castor bean, was the most promising candidate for future evaluation as a biological control agent of M. phaseolina.