关防风根腐病拮抗细菌筛选与鉴定

【背景】由木贼镰刀菌Fusarium equiseti(Corda)Sacc.]引起的关防风根腐病,是近年来导致关防风产量及质量下降的主要土传病害之一。生物防治因其对环境安全及人畜无害等优势,成为目前植物病害防治的一种有效手段。【目的】挖掘关防风根际土壤中对木贼镰刀菌具有良好拮抗作用的生防菌株。【方法】采用稀释平板法分离根际土壤细菌;用滤纸片法和牛津杯法对拮抗细菌进行筛选和抑菌谱检测;用抗生素标记法标记拮抗细菌并测定其定殖能力;通过盆栽实验研究其对关防风根腐病的防效;通过形态学、生理生化特征及16S rRNA基因序列确定分类学地位。【结果】从健康关防风根际土壤中分离纯化了157株细菌,筛选获得对关防风根腐病菌具有显著抑菌作用的拮抗细菌SC-119,无菌滤液的抑菌率可达68.53%,而且兼具广谱抑菌能力和良好的定殖能力;盆栽实验表明,菌株SC-119对关防风根腐病的防治效果达到67.39%,其相对防效较接种哈茨木霉菌剂、枯草芽胞杆菌菌剂和代森锰锌分别提高了29.03%、32.26%和16.13%;对菌株SC-119进行分类学鉴定,确定其为萎缩芽胞杆菌(Bacillus atrophae...

Screening and identification of the antagonistic bacteria against root rot of Saposhnikovia divaricata

Background] Fusarium equiseti (Corda) Sacc. caused root rot is one of the principal soil-borne diseases that have resulted in a decline in the production and quality of Saposhnikovia divaricata in recent years. Because of environmental safety and no harm to humans and animals, biocontrol becomes an efficient approach for the prevention and control of plant diseases. Objective] In order to mine the biocontrol strains with good antagonistic activity against F. equiseti in the rhizosphere soil of S. divaricata. Methods] The dilution plate method was used to isolate bacteria from the rhizosphere soil. The antagonistic bacteria were identified via the filter paper method and the Oxford cup method. Antibiotic labeling was employed to mark antagonistic bacteria and assess their colonization capacity. Pot experiments were carried out to investigate their ability of mitigating root rot. The morphological, physiological and biochemical parameters, as well as the 16S rRNA gene sequence, were used to assess the taxonomic position. Results] A total of 157 strains of bacteria were isolated from the healthy rhizosphere soil of S. divaricata, among which the antagonistic bacterial strain SC-119 with strong activity against F. equiseti was screened out. This strain showed an inhibition rate of 68.53% and exhibited strong colonization capacity and a broad antagonistic spectrum. In the pot experiments, SC-119 showed the control effect of 67.39%, which was 29.03%, 32.26%, and 16.13% higher than that of Trichoderma harzianum, Bacillus subtilis, and mancozeb, respectively. Finally, strain SC-119 was identified as Bacillus atrophaeus. Conclusion] B. atrophaeus SC-119 has good antagonistic effect and biocontrol potential against F. equiseti, serving as an effective source for the biocontrol of root rot in S. divaricata. The findings of this study facilitate the development and utilization of strain SC-119.