槭菌刺孢对5种甾醇脱甲基抑制剂的敏感性

    Sensitivity analysis of Mycocentrospora acerina to five sterol demethylation inhibitors

    • 摘要: 由槭菌刺孢Mycocentrospora acerina (R. Hartig) Deighton引起的圆斑病是危害三七Panax notoginseng (Burk) F. H. Chen的重要叶部病害,严重影响中药材三七的产量和质量。为探索槭菌刺孢对甾醇脱甲基抑制剂类(DMIs)杀菌剂的敏感性,采用菌丝生长速率法测定了45株槭菌刺孢对氟硅唑、苯醚甲环唑、烯唑醇、丙环唑和戊唑醇5种杀菌剂的敏感性,并分析了病原菌对这5种杀菌剂敏感性的相关性。结果表明:氟硅唑、苯醚甲环唑、烯唑醇、丙环唑和戊唑醇对供试菌株的EC50值分别在0.04~3.81、0.18~6.72、0.08~7.75、0.44~11.38和0.46~29.85 µg/mL之间;敏感性频率分布测定结果表明,5种杀菌剂对呈连续单峰频次正态分布的大多数菌株群体的平均EC50值分别为(0.99 ± 0.64)、(1.77 ± 0.97)、(2.37 ± 1.39)、(2.61 ± 1.48)和(3.18 ± 1.58) µg/mL,供试菌株群体中已出现对5种杀菌剂敏感性降低的亚群体,且供试菌株对这5种DMIs杀菌剂均存在较强的交互抗性,而菌株对氟硅唑和苯醚甲环唑的交互抗性相关系数最高,为0.989。本研究结果可为云南省三七圆斑病防治中甾醇脱甲基抑制剂的合理使用提供理论依据。

       

      Abstract: Round spot of Panax notoginseng (Burk) F. H. Chen is a destructive leaf disease, caused by Mycocentrospora acerina (R. Hartig) Deighton. It has serious impacts on the production and quality of the Chinese herbal medicine P. notoginseng. In order to evaluate the sensitivity of M. acerina to five sterol demethylation inhibitors (DMIs), the mycelium growth rate method was used to detect the sensitivity of forty-five strains to flusilazole, difenoconazole, diniconazole, propiconazole, and tebuconazole. The cross resistances were analyzed as well. The EC50 values of flusilazole, difenoconazole, diniconazole, propiconazole, and tebuconazole ranged from 0.04 to 3.81 µg/mL, 0.18 to 6.72 µg/mL, 0.08 to 7.75 µg/mL, 0.44 to 11.38 µg/mL, and 0.46 to 29.85 µg/mL, respectively. The analysis of the frequency distribution range of the EC50 values revealed that the mean EC50 values of five fungicides to the most strains with unimodal continuous curve distribution were (0.99 ± 0.64), (1.77 ± 0.97), (2.37 ± 1.39), (2.61 ± 1.48) and (3.18 ± 1.58) µg/mL respectively. There was a sub-population with reduced sensitivity to five fungicides, and the strains showed significant cross-resistance to the five DMIs fungicides. The cross-resistance correlation index between flusinazole and difenoconazole was 0.989 which was the highest. The results provided the theoretical basis for the rational use of DMIs to control P. notoginseng round spot in Yunnan Province.

       

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