Fungal Root Endophytes from <i>Musa</i> spp. as Biological Control Agents against the Plant Pathogen <i>Fusarium oxysporum</i>

Abstract

Endophytic fungi as biological control agents pose a novel and promising alternative for plant disease management. Thus, our research study aimed to test whether locally isolated banana root endophytes (BRE) can be used as potential biocontrol agents against Fusarium oxysporum (Foc). Seventy-five BREs were isolated from roots samples of banana cultivars collected from different sites in Manila and Quezon City. High species richness was observed from the plants collected in Quezon City. Twenty-five selected isolates were screened for their antagonistic interactions against F. oxysporum using the dual-culture method, but only three of them inhibited the test fungus either on contact (BRE 18 & BRE 71) or at a distance (BRE 14). Morphocultural characterization identified them as belonging to the genus Aspergillus . Further antagonistic testing showed that the three BREs significantly reduced the colony radial growth of F. oxysporum , particularly when the BREs were grown 15 days prior to Foc inoculation. Extraction of secondary metabolites was done to test the antifungal properties of the three BREs. The crude culture extracts failed to inhibit the fungus using the paper disk diffusion assay, though they were able to remarkably decrease spore germination. Thus, the isolated banana root endophytes showed potential application for biological control. Keywords: fungal root endophytes, biocontrol agent, antagonistic activities, Musa spp., Fusarium oxysporum , Aspergillus sp. DOI: 10.3860/acta.v56i0.1491 Acta Manilana 56 (2008) pp.27-35