Screening and identification of antagonistic bacteria against Fusarium oxysporum f.sp. cubense race 4

In order to screen strains of antagonistic bacteria against Fusarium oxysporum f.sp.cubense,87 bacteria strains were isolated from the soil around the cultured banana root,seven strains which had antagonistic effect on Fusarium oxysporum f.sp.cubense(FOC) were screened by pairs-culture,and their inhibitive efficiency on the hyphal growth and conidial germination were tested.The results showed that the antagonistic bacteria strains 255,D5,F2,ZK11,214,215 and 252 had significant inhibition effect on FOC,distorted the mycelium,the induced zone of inhibition ranged from 17.90 to 22.88 mm in diameter on PDA plates,and the inhibition rates to conidial germination ranged from 64.40% to 80.50%.By studying the 16S rDNA sequence and biochemical characters,strain 255,D5 and F2 were preliminary identified as Bacillus cereus,Bacillus thuringiensis and Bacillus licheniformis,respectively.