Management of Cumin Wilt Caused by Fusarium oxysporum Using Native Endophytic Bacteria

Abstract

Eleven endophytic bacteria were isolated from the roots of cumin, a medicinal plant grown in Assiut Province, Egypt. The strains KAU2025 and KAU2022 exhibited the highest inhibition rate against Fusarium oxysporum (FOC7) (64%) in dual culture test and were selected for further studies. KAU2022 and KAU2025 were identified as Brevibacillus parabrevis and Pseudomonas fluorescens, respectively, based on 16S rDNA sequence analysis. The isolates increased the seed germination of cumin by 46.6% compared to that in the control infected with the pathogen F. oxysporum (FOC7). Additionally, the biocontrol efficacy of B. parabrevis against Fusarium wilt in cumin was determined as 67.4% in pot experiments, and both the bioagents increased the fresh and dry weight of the cumin plant compared to the infected control. After a 24 h treatment, the peroxidase levels in the cumin plants were higher in the P. fluorescens and B. parabrevis-treated groups, and the level of polyphenol oxidase increased in both treatments compared to the infected control. The treatment of cumin with both strains increased the total phenol and flavonoid contents in the treated plants. In summary, B. parabrevis and P. fluorescens are promising agents for the biocontrol of Fusarium wilt in cumin.