农抗211对水稻纹枯病菌细胞膜和抗氧化酶活性的影响

Effects of Antifungalmycin 211 on Cell Membrane and Antioxidant Enzyme Activity of Rhizoctonia solani

为探究链霉菌JD211所产活性物质农抗211抑制水稻纹枯病菌(Rhizoctonia solani)的作用机制,采用不同浓度(0.46、0.63、1.26、2.53、4.00、5.06μg·mL^(-1))农抗211作用纹枯病菌,检测纹枯病菌菌丝细胞膜透性和抗氧化系统的变化。结果表明,与对照相比,处理组荧光染料碘化丙啶(PI)染色呈现明显荧光,胞外电导率增加,菌丝总脂质含量降低,表明活性物质处理增加了纹枯病菌细胞膜通透性,导致细胞膜结构遭受破坏。低浓度(0.63μg·mL^(-1))农抗211处理,病菌的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性增强,显示为了减少氧化损伤,病原菌抗氧化系统开始作用。随着农抗211浓度增加,菌体SOD、CAT、POD、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性受到抑制,脂氧合酶(LOX)活性和丙二醛(MDA)含量升高,说明菌丝体内抗氧化系统被破坏,膜脂质过氧化损伤严重,菌体生长受到影响。本研究可为链霉菌JD211的生物防治应用提供理论指导。

To investigate the inhibition mechanism of antifungalmycin 211 produced by Streptomyces sp.JD211 against Rhizoctonia solani,the effects of different concentrations(0.46、0.63、1.26、2.53、4.00、5.06μg·mL^(-1))of antifungalmycin 211 on cell membrane permeability and antioxidant system of R.solani were studied.Compared with the control,the treated group showed more obvious fluorescence of PI,increased extracellular conductivity,and decreased total lipid content of mycelium,indicating that the treatment of active substances increased the permeability of cell membrane,which lead to the destruction of cell membrane structure.The activities of superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)were increased after treatment with low concentration(0.63μg·mL^(-1))of antifungalmycin 211.In order to reduce oxidative damage,the antioxidant system of R.solani began to work.With the increase of concentration of antifungalmycin 211,the activities of five antioxidant enzymes were inhibited,and the activities of Lipoxygenase(LOX)and malondialdehyde(MDA)were increased,which indicated that the function of antioxidant system was destroyed,membrane was damaged by membrane peroxidation,and the growth of R.solani was inhibited.The study on the inhibition mechanism of antifungalmycin 211 on R.solani could provide theoretical guidance for the application of Streptomyces sp.JD211 in biological control.