蓖麻枯萎病菌高效生防菌株LX1的筛选与鉴定

Screening and Identification of Strain LX1 against Fusarium oxysporum

为筛选对蓖麻枯萎病菌Fusarium oxysporum Schl.具有抑制活性的生防菌株，本研究利用利福平选择性培养法，从花生根际土壤中筛选了一株对蓖麻枯萎病菌具有显著抑制活性的菌株 LX1。菌株 LX1在对峙培养中出现了明显的抑菌圈，孢子萌发试验显示孢子萌发抑制率为55%～78%，普通光学显微镜观察显示，菌株LX1可显著抑制F. oxysporum菌丝生长，明显造成菌丝分支增加，部分菌丝顶端和中央膨大，随着时间的延长，畸变结构和程度加剧。通过对菌株LX1的形态特征、染色反应、培养性状、生理生化测试以及16S rDNA分析，鉴定该菌株为枯草芽孢杆菌。本研究结果为菌株LX1应用于蓖麻枯萎病菌的生物防治及生物制剂的开发提供了依据。

In order to select biocontrol strains with strong antagonistic to Fusarium oxysporum Schl., strain LX1 was selected by rifampicin from the peanut rhizosphere. The test results showed that strain LX1 had strong antagonistic activity against F. oxysporum on agar plates with an apparent inhibition zone. The germination rate of conidium was inhibited by 55%-78%when the culture filtrates from strain LX1 were mixed with condia solution in glass slide. Growth suppression, increasing branches of their offset and swelling in the middle and the top of the hyphae were observed with microscope. Strain LX1 was identified as Bacillus subtilis based on its morphological, staining reaction, culture traits, physiological and biochemical determination and 16S rDNA sequence. This research laid the foundation for the biological control of F. oxysporum and the development of strain LX1 for biologics.