四种植物精油对草莓致病菌的协同抑制作用研究

Synergistic Antimicrobial Effect of Four Plant Essential Oils Against Strawberry Pathogen

通过研究肉桂、山苍子、芳樟及丁香四种植物精油及复合精油对草莓致病菌的抑菌效果,筛选出对草莓致病菌优化的复合精油组合。采用直接接触法和熏蒸法、常量稀释法、棋盘稀释法对草莓致病菌进行抑菌评价,并计算FICI指数。实验表明肉桂-山苍子复合精油对沙门氏菌、灰葡萄孢霉具有一定的协同抑菌效果,其FICI均为0.5,MIC分别为0.156、0.625μL/mL。肉桂-山苍子(V∶V=1∶1)精油处理沙氏菌和灰葡萄孢霉的抑菌圈直径最大。通过复合精油处理沙门氏菌、灰葡萄孢霉在内容物泄露、电导率变化及菌体形态扫描电镜(SEM)的实验,复合精油严重破坏菌体结构,细胞膜渗透性增加,破坏胞内离子稳态,核酸等内容物泄露,菌体形态发生皱缩、扭曲,表明复合精油对供试菌具有损伤作用。复合精油之间的协同作用具有更好的抑菌效果,能够减少精油用量,在草莓保鲜应用上前景良好。

The optimal combination of compound essential oils for pathogenic bacteria of strawberries was screened out based on the experimental results of the antibacterial effects of four essential oils and compound essential oils of cinnamon,litsea cubeba,Cinnamomum camphora and clove on pathogenic bacteria of strawberries.The direct contact method,fumigation method,constant dilution method,and checkerboard dilution method were used to evaluate the bacteriostasis of strawberry pathogens,and calculate the FICI value.Experiments showed that the cinnamon-litsea cubeba compound essential oil had a certain synergistic antibacterial effect on Salmonella and Botrytis cinerea with a FICI of 0.5 and MIC of 0.156μL/mL and 0.625μL/mL,respectively.The ratio of 1∶1(V∶V)cinnamon-litsea cubeba essential oil treatment of Salmonella and Botrytis cinerea had the largest inhibition zone diameter.Through the compound essential oil treatment of Salmonella and Botrytis cinerea in the content leakage,conductivity change and bacterial cell morphology scanning electron microscope(SEM)test,the compound essential oil severely destroyed the bacterial structure,increases the permeability of the cell membrane,and destroyed the intracellular ion homeostasis.Nucleic acid and other contents leaked,and the morphology of the bacteria was shrunk and distorted,indicating that the compound essential oil had a damaging effect on the tested bacteria.The synergy between the compound essential oils had a better antibacterial effect,and could reduce the amount of essential oils and had a good development prospect in the application of strawberry preservation.