Biocontrol potential of Burkholderia sp. BV6 against the rice blast fungus Magnaporthe oryzae.

Abstract

To investigate the broad-spectrum antifungal activity of Burkholderia sp. BV6, that is isolated from rice roots and its biocontrol potential against rice blast caused by Magnaporthe oryzae. We evaluated the ability to isolate BV6 in the biological control of rice blast disease and investigated its antifungal mechanisms. BV6 strongly inhibited the hyphal growth of M. oryzae Guy11 and other plant pathogenic fungi, and pot experiments showed that BV6 significantly decreases the disease index of rice blast from 47.5 to 24.6. The secreted small-molecule secondary metabolites were regarded as weapons during the antifungal process by inhibiting the germination of M. oryzae conidia and mycelial growth, and thereby prevent the following infection. Liquid chromatography-mass spectrometry analysis of the metabolites from the supernatant of isolate BV6 showed that the antifungal weapons of isolate BV6 are novel, small, molecular hydrophilic compounds that are different from reported antifungal compounds. The isolate BV6 inhibits the M. oryzae infection by the production of small-molecule antifungal compounds. The current study discovers the role of the Burkholderia sp. BV6 in the biocontrol of plant pathogenic fungi. Therefore, isolate BV6 is a potential candidate for developing a microbial formulation for the biocontrol of the most common disease of rice blast.