新型农抗N2粗提物对水稻纹枯病菌细胞膜和抗氧化功能的影响

Effects of the Crude Extract From Streptomyces sp. N2 on Cell Membrane and Antioxidant Function of Rhizoctonia solani

为揭示新型拮抗真菌剂农抗N2抑制水稻纹枯病菌的作用机制,采用高效液相色谱法(HPLC)、分光光度法(SP)和荧光显微镜(FM)研究农抗N2粗提物对水稻纹枯病菌细胞膜成分、抗氧化酶活性、活性氧(ROS)积累以及脂质过氧化的影响。结果表明,不同浓度农抗N2粗提物处理后水稻纹枯病菌丙二醛(MDA)含量显著高于对照,且荧光强度急剧增强。此外,低浓度农抗N2粗提物处理可有效激活菌体的抗氧化防御系统(SOD、CAT、POD、PAL和PPO),随着农抗N2粗提物浓度升高,抗氧化酶活性受到抑制,抗氧化功能显著降低;高浓度农抗N2粗提物处理组中菌丝麦角甾醇合成抑制率达80%左右,细胞膜结构遭受破坏。农抗N2粗提物能显著抑制麦角甾醇的合成并破坏病原真菌细胞膜,使水稻纹枯病菌脂质过氧化,大量积累ROS造成氧化损伤,导致其抗氧化功能丧失。本研究对新型拮抗真菌剂农抗N2生物防治的应用具有重要的指导意义。

To investigate the antagonistic mechanism of a novel antifungalmycin N2 against Rhizoctonia solani. The effects of antifungalmycin N2 crude extracton on the cell membrane composition,antioxidant enzyme activity,reactive oxygen species（ROS） accumulation and lipid peroxidation of R. Solani were investigated. By using high performance liquid chromatography（HPLC）,spectrophotometry（SP） and fluorescence microscopy（FM）. Results showed that the content of malondialdehyde（MDA） was increased significantly,and the fluorescence intensity was increased rapidly under the treatment with antifungalmycin N2 crude extract; Low concentration of antifungalmycin N2 crude extract could availably activate the antioxidant defense system,and the antioxidant enzyme activity（SOD,CAT,POD,PAL and PPO） was significantly inhibited and the antioxidant function was decreased significantly with the increasing concentration of antifungalmycin N2 crude extract; In the group treated with high concentration of antifungalmycin N2 crude extract treatment group,the mycelium of ergosterol synthesis inhibition rate was about 80%,and the structure of cell membrane. In conclusion,the antifungalmycin N2 crude extract could significantly inhibit the ergosterol synthesis,destroy the cell membrane,lead to the lipid peroxidation,and cause oxidative damage by massive accumulation of reactive oxygen species ROS,resulting in loss of the antioxidant function in R. solani. The results of this study will provide theoretical guidance for the application of new antifungal agent antifungalmycin N2 in biological control.