疮痂链霉菌拮抗菌株BU396的分离鉴定与抗菌性质分析

Isolation, identification and antimicrobial properties of a biocontrol strain BU396 against Streptomyces scabies

摘要:

【背景】随着马铃薯种植面积的扩大，疮痂病的发生也日益严重，且化学防治存在环境污染等诸多弊端，因此利用安全和高效的生物防治手段对该病害进行防治成为研究热点。【目的】对疮痂链霉菌(Streptomyces scabies)拮抗菌株进行分离、鉴定和功能基因分析，对抗菌物进行分离及抗菌特性的研究。【方法】从马铃薯疮痂病的病害土壤中分离、筛选并鉴定得到拮抗菌株，采用PCR法对菌株进行抗菌物合成基因检测。通过硫酸铵沉淀法分离得到抗菌物，进行抗菌谱和稳定性检测，并通过盆栽试验进一步验证该菌株的生防效果。【结果】通过抗菌试验筛选得到拮抗细菌BU396，根据形态学、生理生化性质和分子生物学鉴定结果，确定其为贝莱斯芽孢杆菌(Bacillus velezensis)。功能基因分析表明BU396中含有表面活性素等4种抗菌物的合成相关基因。采用硫酸铵沉淀法对其培养液上清进行分离，当硫酸铵的饱和度为75%时，抗菌物在沉淀中析出。抗菌谱试验结果显示该抗菌物对多种动植物病原菌均具有抗菌效果。稳定性试验表明该抗菌物耐热，不易被酶解，对多种金属离子不敏感，具有宽泛的pH活性范围，盆栽试验结果显示菌株BU396处理能够明显降低马铃薯疮痂病的发病率。【结论】分离并鉴定了一株对疮痂链霉菌具有显著拮抗作用的贝莱斯芽孢杆菌BU396。该菌株含有多种抗菌物合成的相关基因，其抗菌物具有广谱的抗菌活性和良好的稳定性，对马铃薯疮痂病的生防效果显著。本研究为马铃薯疮痂病的生物防治及后续抗菌物质的深入研究奠定了基础。

Abstract:

[Background] With the expansion of potato planting area, the occurrence of potato scab disease becomes more and more serious. Chemical control of potato scab caused a serial of problems like environmental pollution. Therefore, biological control with safety and efficiency becomes the focus of the current research. [Objective] To isolate and identify an antagonistic strain against Streptomyces scabies, and analyze its functional genes. To isolate the antimicrobial?substance and characterize its antimicrobial features. [Methods] The antagonistic strain was screened and identified from the soil with potato scab disease, and the functional genes were analyzed by PCR. The antimicrobial?substance was separated by ammonium sulfate precipitation method, and its antimicrobial spectrum and stability were tested. The biocontrol effect of the antagonistic strain was further verified by pot assay. [Results] An antagonistic strain BU396 was obtained by antimicrobial tests, which was identified as Bacillus velezensis according to its morphological characteristics, physiological and biochemical properties and molecular identification results. Functional genes analysis showed that BU396 contained four antimicrobial peptide synthesis related genes. The antimicrobial substance was precipitated from the supernatant of culture medium by ammonium sulfate precipitation with 75% saturation. The antimicrobial spectrum test showed that the antimicrobial substance could inhibit several plant and animal pathogens. The stability tests showed that the antimicrobial substance had good stability with thermal, protease, metal ions and wide pH value. Pot assay result showed that the incidence of potato scab was significantly reduced by BU396 treatment. [Conclusion] In this study, Bacillus velezensis BU396 with significant antagonism against Streptomyces scabies was isolated and identified, which was further detected containing several antimicrobial peptide related genes. The antimicrobial substance of BU396 had broad-spectrum antimicrobial activity and good stability. Moreover, it was also proved that BU396 had remarkable biocontrol effect against potato scab. This study lays the foundation for biological control of potato scab and further study of antimicrobial substances.