短短芽胞杆菌对植物病原真菌的抑菌活性和抑菌机理
The antifungal activity and mechanism of Brevibacillus brevis on plant pathogenic fungus

为探讨短短芽胞杆菌菌株011对植物病原真菌的防控效果，采用平皿打孔法测定菌株011粗提液对14种植物病原真菌的抑制作用，并以番茄早疫病为研究对象，研究了其抑菌机理。结果显示，菌株011粗提液对14种病原真菌均有抑菌活性，其中对番茄早疫病菌的抑菌活性最强，抑菌率达45.9%；菌株011粗提液能导致番茄早疫病菌菌丝生长异常，抑制孢子萌发；对番茄早疫病菌菌丝生长的EC50为71.4 mg/mL，对孢子萌发的EC50和MIC分别为0.12 mg/mL和0.8 mg/mL；该粗提液能引起番茄早疫病菌菌丝的脂质过氧化程度和细胞内过氧化氢含量上升，菌丝细胞膜的蛋白质合成量下降，当粗提液浓度高于50 mg/mL时，菌丝细胞膜的麦角甾醇合成量下降；该粗提液还能降低番茄早疫病菌胞外果胶酶和纤维素酶的活性。研究表明，菌株011粗提液可作为生防制剂应用于植物病原真菌的防治。
In order to explore the control efficacy of Brevibacillus brevis 011 strain, 14 plant pathogenic fungi were selected to evaluate their antagonistic activity by using plate-perforation method, and the antifungal mechanism of crude extracts on Alternaria sonali was also determined. The results showed that the crude extracts of 011 strain had inhibitory effects on 14 pathogens, and showed the strongest inhibitory effect on Alternaria sonali, with an inhibition ratio of 45.9%. The treatment of crude extracts resulted in the pathogen mycelia growing in abnormal shape and the germination of spores was also inhibited. The EC50 of crude extracts on Alternaria sonali mycelial growth was 71.4 mg/mL. The EC50 and MIC of crude extracts on Alternaria sonali spores were 0.12 mg/mL and 0.8 mg/mL, respectively. The crude extracts also caused damage to cytoplasmic membrane including induction of lipid peroxidation, increase of hydrogen peroxide content in the cell and the decline of protein synthesis in mycelial membrane. When the concentration of crude extracts was over 50 mg/mL, it also expressed obvious inhibitive effect on ergosterol synthesis. The activities of pectinase and cellulose were both significantly lower than those of control after treatment with crude extracts. Therefore, the crude extracts of 011 strain could be a bioagent for control of plant pathogenic fungus.