Isolation and characterization of rhizosphere bacteria antagonistic to Fusarium oxysporum f. sp. sesame, a cause of wilt disease on sesame plant

The study aimed to isolate bacteria from the sesame root rhizosphere that can antagonize the fungus Fusarium oxysporumf.sp. sesami. The fungus that caused wilt disease in the sesame plants was isolated from naturally infected samples and was thenartificially introduced into the healthy sesame seedling to confirm the disease symptom. In parallel, rhizosphere soils of thesesame root collected in Bac Kan, Vietnam were used to isolate bacteria by serial dilution method. The isolated bacteria were thenused to screen for their ability in inhibiting the Fusarium oxysporum f.sp. sesami at either in vitro or field. Among 30 isolatedbacteria, only 7 of them could antagonize Fusarium oxysporum f.sp. sesami with antibacterial efficiency ranged from 6.15 to72.17%. Among 7 antifungal isolates, three isolates (NR11, NR22, and NR26 identified as Bacillus cereus KN4, Bacillusamyloliquefaciens B7, and Bacillus pumilus B19) could produce siderophore and degraded cellulose, protein, and chitin. These isolates reduced wilt-disease symptoms and promoted seedling development in sesame under greenhouse and field conditions.These results suggest that NR11, NR22, and NR26 strains could be applied as biocontrol agents in sustainable agriculture.

DOI: 10.30848/PJB2024-2(12)