Purpose To clarify the biocontrol effects of Bacillus amyloliquefaciens OMR1-7 against Fusarium oxysporum causing black rot disease in Echeveria succulent plants.
Methods The endophytic bacterial strain OMR1-7 isolated from the root tissues of Oryza minuta was identified as B. amyloliquefaciens in this study. The antagonistic effects of B. amyloliquefaciens OMR1-7 against F. oxysporum KMEARM-2 on E. agavoides cv. ‘Romeo’ and F. oxysporum KMJY6 on E. derenbergii cv. ‘Purpus’, the pathogens causing black rot disease in succulent plants of the genus Echeveria, was evaluated. Furthermore, its ability to produce iron carriers and biofilms, colonization capacity, and greenhouse efficacy were also determined.
Results The hyphal growth suppressive rates and colony inhibition rates of this antagonistic bacterium against these two pathogens were determined to be 57.15%-74.29% and 84.82%-86.15%, respectively. Due to the antagonistic effect of B. amyloliquefaciens OMR1-7, these two pathogens produced abnormal hyphae and decreased sporulation. B. amyloliquefaciens OMR1-7 produced siderophores with a relative yield of 80.98%, indicating the strong competition for iron. This strain formed biofilms to colonize in the root, stem and leaf tissues of plants, which could prevent the invasion and spread of F. oxysporum. Furthermore, the biocontrol efficiency of B. amyloliquefaciens OMR1-7 against pathogens of E. agavoides cv. ‘Romeo’ and E. derenbergii cv. ‘Purpus’ black rot disease in the greenhouse was determined to be 80.08% and 78.89%, respectively.
Conclusion The results will provide the biocontrol microbial resource, which can develop the microbial fungicide, for preventing black rot disease in Echeveria succulent plants.
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