ANTAGONIST ACTIVITY OF Pseudomonas fluorescens and Burkholderia cepacia STRAINS AGAINST RICE AND MAIZE PHYTOPATHOGENIC FUNGI

摘要

Plant Growth Promoting Bacteria (PGPB) has been proved to exert a beneficial effect on crop yield, directly or indirectly. This work was aimed to determine the antagonistic activity and inhibitory effect exerted on different plant pathogens by rhizobacteria. A number of bioassays was carried in vitro in King B medium. Previously isolated bacterial strains of Pseudomonas fluorescens and Burkholderia cepacia, from corn plants var. Francisco mejorado, were assayed to determine their potential as antagonists of the phytopathogenic fungi Fusarium oxysporum, Alternaria alternata, Curvularia sp. and Fusarium sp. The results showed the capability of inhibiting the pathogen growth by the rhizobacterial strains, proving the best behaviour the strains P. fluorescens MPf2, MPf3, J-143 and B. cepacia MPp8. It was shown that there was a greater inhibitory effect on the fungi strains Curvularia sp. A1 and A. alternata M2. Considering these results, the bacterial strains were competent for pathogen biocontrol, and could be used in agriculture as valuable growth promoting agents in maize and rice crops.