附子白绢病拮抗细菌的分离鉴定及发酵条件优化

Isolation,identificationandfermentationconditionsoptimization of antagonistic bacteria against southern blight on Aconitum carmichaeli

  • 摘要: 【目的】从黄粉甲中分离获得对附子白绢病病原菌具有较好抑制作用的拮抗细菌,为附子白绢病的生物防治提供菌种资源。【方法】以罹病黄粉甲为材料,通过稀释涂布法和平板对峙法分离并筛选对附子白绢病菌具有拮抗作用的细菌,通过形态结构、生理生化特征及16S rDNA序列分析等对拮抗细菌进行种类鉴定;以拮抗细菌发酵液在600 nm波长下的OD值为指标,采用单因素试验的方法对拮抗细菌的培养基组分以及发酵条件进行优化;通过室内盆栽试验明确拮抗细菌对附子白绢病的防治效果。【结果】采用稀释涂布法从罹病黄粉甲中分离获得4株细菌,经平板对峙法筛选获得对附子白绢病菌具有较好拮抗效果的菌株TS1,该菌对齐整小核菌菌丝生长的抑制率可达68.03%。根据菌株TS1的菌落形态结构、生理生化特征及16S rDNA序列分析结果,确定菌株TS1为枯草芽孢杆菌(Bacillus subtilis)。菌株TS1的优化培养基配方:蛋白胨10.0 g/L、酵母浸粉5.0 g/L、麦芽糖15.0 g/L;最佳发酵条件:装液量30mL、初始接种量0.50%、转速210 r/min、培养温度42℃、初始pH 9、培养时间48 h。室内盆栽保护和治疗试验结果表明,菌株TS1对附子白绢病的平均防治效果分别为49.39%和62.97%。【结论】优化的发酵方案可用于快速、大批量培养菌株TS1菌悬液。菌株TS1对附子白绢病有较好的防治效果,具有开发成附子白绢病生防菌的潜力。

     

    Abstract: 【Objective】 This study screened and obtained antagonistic bacteria with good inhibitory effect on the pathogen of southern blight on Aconitum carmichaeli from Tenebrio moliter,so as to provide strain resources for the biological control of southern blight on A. carmichaeli.【Method】 Using diseased T. moliter as the material,the bacteria with antagonistic effect on southern blight on A. carmichaeli was isolated and screened by dilution coating and plate confrontation methods. The antagonistic bacteria was identified by morphological,physiological and biochemical characteristics and 16S rDNA sequence. With the OD value of bacterial fermentation broth at 600 nm as the index,the culture medium components and fermentation conditions of antagonistic bacteria were optimized by single factor experiment. The control effect of antagonistic bacteria on southern blight on A. carmichaeli was confirmed by pot experiment in laboratory.【Result】 Four strains of bacteria were obtained from T. moliter by dilution coating method. And TS1 strain with greater antagonistic effect against southern blight on A. carmichaeli was obtained by plate confrontation method,with an average inhibitory rate for Sclerotium rolfsii mycelial growth of 68.03%. The TS1 strain was identified as Bacillus subtilis based on its morphological,physiological and biochemical characteristics and the result of 16S rDNA sequence analysis. The optimized medium formula was peptone 10.0 g/L,yeast extraction powder 5.0 g/L and maltose 15.0 g/L. The optimal fermentation conditions were 30 mL of liquid,0.50% of initial inoculum,210 r/min of rotation speed,42 ℃ of temperature,initial pH 9,and 48 h of incubation. The results of laboratory pot experiment and experimental treatment showed that the average control efficiency of TS1 strain against southern blight on A. carmichaeli were 49.39% and 62.97% respectively.【Conclusion】The optimized fermentation scheme can be used to rapidly culture TS1 strain suspensions in large quantities. TS1 strain has a good control effect on southern blight on A. carmichaeli and has the potential to be developed into a biocontrol bacterium for southern blight on A. carmichaeli.

     

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