烟草野火病菌拮抗细菌的筛选及其应用研究

从牡丹江烟草科学研究所试验田采集不同品种的健康烟叶30份,利用稀释分离法分离到287株细菌,采用平板对峙法筛选出对烟草野火病菌(Pseudomonas syringae pv.tabaci)具有拮抗作用的菌株14株.拮抗性最好且稳定的菌株Y32经生理生化特性和16S rDNA测序鉴定为枯草芽孢杆菌(Bacillus subtilis).为测定拮抗细菌Y32在烟草叶片中的定殖能力,对Y32进行利福平抗性诱导试验.结果表明,利福平抗性诱导后该菌株对野火病菌的抑制作用显著低于原始菌株,并且在培养基上菌落呈透明状,无法计数,因此,利福平抗性标记不适于Y32在烟草叶片中的定殖能力研究.发酵优化试验结果表明,拮抗细菌Y32最佳实验室发酵配方为:氮源1%(酵母膏 蛋白胨=5 3),葡萄糖0.1%,NaCl 0.3%,KNO30.5%;最佳培养条件为:发酵温度28℃,培养基pH 7.0~7.5,接种量4%,装液量为250 mL三角瓶中装液50 mL.田间试验结果表明,发酵条件优化后Y32防效达到71.6%,显著高于发酵条件优化前和对照药剂甜叶桔,具有进一步研究价值.

Screening of antagonistic bacterial strains against Pseudomonas syringae pv.tabaci

A total number of 287 bacterial strains were isolated from 30 healthy tobacco leaves from the experimental field of the Tobacco Research Institute of Mudanjiang by tube dilution assay.The result of plate test showed that 14 strains had antagonistic activity against the pathogen of wildfire disease.Strain Y32 was selected as one of the best effect.The result of 16S rDNA identification showed that this bacterium belonged to B.subtilis.The optimal fermentation medium components and the best optimal fermentation conditions for strain Y32 were studied.The results were as the following: the medium of fermentation for Y32 constituted of 1% of nitrogen resource(yeast extract..peptone=5..3),0.1% of glucose,0.3% of sodium chloride,0.5% of potassium nitrate.The field experiments showed that control efficiency of optimized strain Y32 fermentation on tobacco wildfire was 71.6%,which showed significantly higher than the effect of wild strain Y32,chemical fungicide Tianyeju,with further research value.