玉米大斑病生防细菌筛选、鉴定与发酵优化

Screening,Identification and Fermentation Optimization of Biocontrol Bacteria against Setosphaeria turcica

为探寻玉米大斑病的生物防治新途径,从而有效地控制玉米大斑病对玉米安全生产的危害,以玉米大斑病菌(Setosphaeria turcica)为指示菌,从长白山土壤中筛选出1株CB113对多种病原真菌都具有较强抑菌活性的菌株,根据该菌株形态培养特征、生理生化特征、16S r DNA序列分析结果,CB113菌株被鉴定为荧光假单胞菌(Pseudomonas fluorescens)。通过单因子变量法和正交设计法对菌株CB113进行了发酵条件优化,结果表明:该菌株最佳发酵条件为p H 7,装瓶量40 m L/250m L,发酵时间60 h,接种量1%,果糖3.0%,蛋白胨1.0%,磷酸二氢铵0.2%,Mg SO4·7H2O 0.2%。经优化后,菌丝生长抑制率最高达到77.35%,比优化前提高了21.54%。该研究结果表明,CB113在玉米大斑病的生物防治有潜在的利用价值。

In order to explore the prevention and control agents for the pathogen of corn speckle,to control the spread of the disease in maize production,with setosphaeriaturcica（ Setosphaeria turcica）as the indicator bacteria,a strain of CB113 with strong antibacterial activity to various pathogenic fungus strains from Changbai Mountain soil was screened. Combined with the morphological,physiological and biochemical characteristics of the strain and the results of 16 S r DNA sequence analysis,strain CB113 was identified as Pseudomonas fluorescens（ Pseudomonas fluorescens）. By single factor method and orthogonal design method,fermentation conditions of strain CB113 were optimized. The results showed that the optimum fermentation conditions of the strain were p H 7,bottling volume40 m L/250 m L,fermentation time 60 h,inoculum 1%,fructose（ 3%）,peptone（ 1%）,two ammonium hydrogen phosphate（ 0. 2%）,and Mg SO4·7 H2 O（ 0. 2%）. After optimization,the inhibition rate of mycelial growth reached 77. 35%,which was increased by 21. 54% compared with that beforeoptimization. CB113 has potential utilization value in biocontrol of Setosphaeria turcica.