Screening and Identification of Antagonistic Bacterium against Colletoichum wilt

In order to obtain antagonistic bacteria against Fusarium oxysporium,237 bacillus strains were isolated and screened from soil samples of different districts.A bacillus strain 3A3-15 collected from cotton soil of Raoyang County in Hengshui was obtained via preliminary screening and secondary screening.It had strong and broad-spectrum inhibition capability.We characterized the strain 3A3-15 by morphological and culture features observation,physiological and biochemical experiments,and 16S rDNA sequence analysis.As the similarity of the 16S rDNA sequences between strain 3A3-15 and the type strain CR-502 was up to 99.92%,the strain 3A3-15 was finally identified as Bacillus velezensis.