关键词: 燕麦, 根腐病, 生物防治, 抑菌特性

Abstract: Screening the bacteria that can control oat root rot and studying their antibacterial properties are important for further development of bio-pesticides. The plate confrontation method was used to screen the strains that could antagonize oat root rot pathogen (Fusarium graminearum) from healthy oat rhizosphere. At the same time,the biocontrol strains acquired in the previous study were included in the screening test. The capability of producing protease,cellulase,amylase and iron-carrier/siderophore activity of the strains was determined by adopting a transparent circle method,The strains were screened for the second time,and the strains with excellent enzyme-producing ability were quantitatively determined. The acid precipitation method was used for the crude extraction of lipopeptide and its antibacterial ability was verified. Finally,the strains with excellent biological control properties were identified by 16S rRNA. The results showed that 4 strains with excellent comprehensive characteristics were obtained,and the antibacterial ratio was more than 65%. The activity of iron carrier,protease activity,cellulase activity and amylase activity was 34.33%~59.57%,36.88~70.12 U·mL^-1,7.68~22.28 U·mL^-1 and 80.56~167.26 U·mL^-1,respectively. The highest inhibitory rate of lipopeptide substances secreted by the strain on the pathogenic bacteria was 68%. Through 16S rRNA identification,the 4 strains were Bacillus subtilis, Bacillus velezensis, Bacillus atrophatus and Paenibacillus peoriae,respectively. In this study,we found 4 biocontrol bacteria can secrete a variety of antibacterial substances,and have the potential for further development as biocides (antibacterial).

Key words: Oats, Root rot, Biological control, Bacteriostatic characteristics