烟草根黑腐病拮抗内生细菌的筛选及其抑菌作用

Inhibition effect and screening of antagonistic endophytic bacteria against Thielaviopsis basicola

【目的】从烟草根、茎中分离获得对烟草根黑腐病菌(Thielaviopsis basicola)有较好控病作用的内生细菌。【方法】采用平板对峙培养,测定分离获得的306个内生细菌对烟草根黑腐病菌的抑制作用;通过菌株形态特征、生理生化特性及16S rDNA序列对菌株进行分类鉴定。【结果】筛选获得6个菌株对烟草根黑腐病菌有较强拮抗作用,室内测定其对病原菌的抑菌带宽达6.5 mm-11.0 mm,温室控病效果达11.9%-77.1%,其中来自茎部的内生细菌T295菌株对烟草根黑腐病的防效达77.1%;无菌滤液实验表明,拮抗内生细菌T295无菌滤液在实验浓度范围内对病菌菌丝生长、孢子萌发有较好地抑制作用。【结论】菌株T295对烟草根黑腐病具有较好的防治作用,经鉴定为枯草芽孢杆菌(Bacillussubtilis)。

[Objective] Screening the antagonistic endophytic bacteria against Thielaviopsis basicola from inner of tobacco roots and stems collected from Chongqing. [Methods] The antagonistic effect of 306 endophytic bacteria against Thielaviopsis basicola by pairing culture on PDA plates, the strain was identified by morphological, physiological and biochemical characteristics, and homology analysis of the partial sequence of 16S rDNA. [Results] Six endophytic bacteria were showed high antagonistic effect against Thielaviopsis basicola, the pathogen of tobacco black root rot. The inhibition zone diameters were ranged from 6.5 mm to 11.0 mm by pairing culture on PDA plates, and the control efficacy ranged from 11.9% to 77.1% in a greenhouse experiment. It was found that strain T295 could reduce the incidence of tobacco black root rot, the control efficacy reaching to 77.1%, and the culture filtrate of strain T295 could inhibit hyphal growth and reduce spore germination of T. basicola. [Conclusion] Strain T295 had a good antagonistic effect on Thielaviopsis basicola, was identified as Bacillus subtilis.