胡麻枯萎病生防芽孢杆菌筛选及抑菌效果研究

Screening of biocontrol bacillus against Fusarium wilt and control effects in linseed

为筛选拮抗胡麻枯萎病菌的生防微生物,对采自我国不同省份胡麻根围土壤进行了细菌分离和拮抗菌筛选。根据土样中151株病原菌尖孢镰刀菌[Fusarium oxysporum f.sp.lini(FOL)]对峙培养获得21株拮抗芽孢杆菌,其中XJ2-20拮抗效果最好,盆栽实验的胡麻枯萎病防效可达56.3%,经鉴定为枯草芽孢杆菌。菌株XJ2-20对151株镰刀菌株的抑菌率最高可达64.5%,其发酵滤液可抑制尖孢镰刀菌生长及抑制分生孢子萌发。菌株XJ2-20的抑菌活性物质的最佳硫酸铵沉淀浓度为70%,活性物质对热和胰蛋白酶敏感,最适pH为7。其最佳发酵条件为LB液体培养基(初始pH 7.2)、每300mL三角瓶装液量50～100mL,29℃培养5d。

Biological control microorganism was isolated from pathogenic soil of linseed.Inhibition rates to Fusarium oxysporum f.sp.lini were evaluated using 151 fungus isolates from different provinces.A bacterial XJ2-20 from 21 antagonistic Bacillus strains showed strong antagonistic effect on the 151 fungus isolates.Its highest inhibition rate was 64.5%.Fermentation filtrate of XJ2-20 affected mycelium growth and spore bourgeoning.Its efficiency of control was as high as 56.3% in pot experiment.Optimized fermentation of XJ2-20 was under 29℃ and pH7.2 with 50 to 100mL LB medium in 300mL-flask for 5d.Antagonistic substance of XJ2-20 was extracted by 70%（NH4）2SO4 precipitation at pH7.The extracted crude protein inhibited pathogens by leading to mycelium rupture,distortion,and inhibiting bourgeoning of spores,although it was sensitive to heat and tryroteinase.