| 摘要: |
| 【目的】明确内生细菌EDR2菌株的分类地位以及对油菜菌核病的防治作用，为该菌株的进一步应用奠定基础。【方法】采用皿内和温室盆栽试验，测定菌株EDR2对油菜菌核病菌菌丝生长和菌核萌发的抑制作用以及对病害的防治效果；并结合菌体形态观察、生理生化特性测定以及16S rDNA序列分析确定该菌株的分类地位。【结果】内生细菌EDR2菌株能够有效抑制油菜菌核病菌的菌丝生长，并可导致菌丝出现畸形、细胞质外渗，同时其还对病菌的菌核萌发具有较强的抑制作用，培养原液的抑制率可达到96.6%。温室盆栽试验结果表明，菌株EDR2的培养原液和无菌培养滤液对苗期油菜菌核病均有良好的防治效果，其防效都在80%以上；菌株EDR2的喷施时间可影响其防治效果，其中以接种病菌前1 d喷施防治效果最好，可达到95.4%；培养原液及不同倍数稀释液对病害的防治效果明显不同，随着稀释度的增加，其生防效果降低。菌株EDR2对供试的16种植物病原菌的菌丝生长均表现出一定的抑制作用，表现出较广的抑菌谱。结合形态和培养特征、生理生化特性及分子生物学鉴定结果认为，内生细菌EDR2属于枯草芽孢杆菌（Bacillus subtilis）。【结论】综合皿内及温室盆栽试验结果认为，内生枯草芽孢杆菌EDR2是1株对油菜菌核病具有较好防治潜力和开发前景的生防菌株。 |
| 关键词: 枯草芽孢杆菌 油菜菌核病菌 菌丝生长 菌核萌发 |
| DOI： |
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| 基金项目:国家公益性行业（农业）科研专项（201103016）；高等学校学科创新引智计划项目（B07049） |
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| Identification and biocontrol efficacy of endophytic bacterium EDR2 against Sclerotinia sclerotiorum |
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| Abstract: |
| 【Objective】The study was conducted to investigate the effect of strain EDR2 on oilseed rape Sclerotinia stem rot and strain identification.【Method】Inhibitory effects of strain EDR2 on mycelial growth,sclerotia germination,and biocontrol efficacies were evaluated in vitro and in vivo.The strain was identified based on the morphology,physiological and biochemical characteristics and 16S rDNA sequence analysis.【Result】Strain EDR2 could strongly inhibit the growth of mycelial and cause leakage and disintegration of hyphal cytoplasm of mycelial cell from Sclerotinia sclerotiorum.In petri dish,strain EDR2 could inhibit both mycelial growth and sclerotia germination;the inhibitory rate was up to 96.6%.In the greenhouse,the culture filtrates of strain EDR2 displayed effective biocontrol activities in the seedlings and the biocontrol efficacy exceeded 80%.The biocontrol activities were influenced by the spraying time of strain EDR2.The control efficacy was higher when strain EDR2 was applied prior to inoculation of the pathogen than after inoculation.Different dilution factors of fermentation showed different inhibitory effects on S.sclerotiorum.As the increase of dilution factor,the biocontrol efficacies declined.Furthermore,strain EDR2 also showed a broad antifungal spectrum on mycelium growth of numerous important plant pathogenic fungi.According to the morphology,physiological and biochemical characteristics,and 16S rDNA sequence analysis,strain EDR2 was identified as Bacillus subtilis.【Conclusion】Our results suggest that endophyic B.subtilis strain EDR2 is a promising biological control agent for Sclerotinia stem rot. |
| Key words: Bacillus subtilis Sclerotinia sclerotiorum mycelia growth sclerotia germination |
