火龙果病原菌的分离鉴定及百里酚的抑菌研究

Study on the isolation and identification of pathogen from Hylocereus undatus fruit and the antibacterial activity of thymol

中文关键词:  火龙果  病原菌  分离鉴定  百里酚  抑菌作用

英文关键词:Hylocereus undatus  pathogen  isolation and identification  thymol  antifungal effect

中文摘要:

      目的 分离鉴定望谟县火龙果病原菌, 并探究百里酚对其的抑菌效果。方法 通过组织分离法、科赫法则、形态学结合ITS序列分析, 确定火龙果软腐病病原菌的种类。通过碘化丙啶(propidium iodide, PI)染色探究百里酚对病原菌细胞膜的破坏作用。结果 引起火龙果软腐病病原菌为水稻恶苗病菌(Fusarium fujikuroi, F. fujikuroi)和弓形镰刀菌(Fusarium arcuatisporum, F. arcuatisporum)。体外实验表明, 两株病原菌对百里酚均有较高的敏感性, 其抑菌率呈剂量浓度依赖效应。百里酚对致病菌F. fujikuroi和F. arcuatisporum的抑制率分别达92.15%和92.42%, 半最大效应浓度(concentration for 50% of maximal effect, EC50)分别为0.2005 mg/mL和0.1560 mg/mL。PI染色发现, 百里酚通过破坏菌丝细胞膜结构完整性发挥其抑菌作用, 使得百里酚处理后菌丝荧光强度明显高于对照。结论 百里酚能较好地抑制火龙果2株病原菌的菌丝生长, 抑制火龙果软腐病发生, 可为火龙果病害防控提供一定理论参考。

英文摘要:

      Objective To isolate and identify the pathogen of Hylocereus undatus fruit in Wangmo County, and explore the antifungal effect of thymol on it. Methods The pathogen species of soft rot of pitaya were determined by tissue separation method, Koch’s rule, morphology and ITS sequence analysis. The destructive effect of thymol on pathogen cells was investigated by propidium iodide (PI) staining. Results The pathogens causing soft rot of pitaya were Fusarium fujikuroi (F. fujikuroi) and Fusarium arcuatisporum (F. arcuatisporum). In vitro experiments showed that the 2 pathogenic fungi had high sensitivity to thymol, and the bacteriostatic rate was dose-dependent. The inhibition rates of thymol against F. fujikuroi and F. arcuatisporum were 92.15 % and 92.42 %, respectively, and the concentration for 50% of maximal effect (EC50) were 0.2005 and 0.1560 mg/mL. PI staining showed that thymol exerted its bacteriostatic effect by destroying the integrity of the cell membrane structure of the mycelium, so that the fluorescence of the mycelium after thymol treatment was significantly higher than that of the control. Conclusion Thymol can inhibite the mycelial growth of 2 pathogens of pitaya and inhibite the occurrence of soft rot of pitaya, which provides a theoretical reference for the prevention and control of pitaya diseases.