Screening and identification of biocontrol bacterium against lotus rhizome rot disease

ObjectiveThe present study screened and identified the biocontrol bacteria against Fusarium commune,in order to provide reference for healthy planting of lotus and effective control of lotus rhizome rot disease.Method Inhibition zone method and confrontation culture were employed to screen the biocontrol bacteria which had strong antagonism against F.commune out of 106 tested antagonistic bacteria.The biocontrol bacteria were identified according to morphology,physiology,biochemistry and molecular identification.Through confrontation culture with six phytopathogenic fungi,antimicrobial spectrum of the biocontrol bacteria was studied.Field control effects of biocontrol bacterium were explored through field experiment.ResultFour biocontrol bacteria with antagonism against lotus rhizome rot disease were selected out of 106 tested strains.Antagonist effects of strain DR1 was the best.Its bacteriostasis band width was 9.8 mm.Strain DR1 enjoyed wide antimicrobial spectrum,and showed inhibitory effects towards six tested phytopathogenic fungi.The field experiment results showed that average control effect of strain DR 1 was 41.83%.Strain DR1 was identified as Bacillus amyloliquefaciens for its biochemical characteristics based on 16S rDNA and gyrB gene sequence analysis.ConclusionB.amyloliquefaciens has strong antagonism effect,heat resistance,strong stress resistance,and broad antimicrobial spectrum.Therefore,it possesses promising developing and applying prospect in lotus disease control.