This study was conducted to evaluate inhibitory effect of natamycin against three isolates of Sclerotinia sclerotiorum, the causal agent of carrot white mold in postharvest phase. The results showed that natamycin was able to markedly decrease radial growth and sclerogenesis of three isolates of the pathogen. In addition, natamycin significantly reduced myceliogenic and carpogenic germinations of sclerotia in three isolates. There was a clear positive correlation between natamycin concentration and efficacy against mycelial growth, sclerogenesis, and sclerotia germinations. Application of natamycin on carrot roots 2.5 h before inoculation with the pathogen markedly reduced white mold incidence. The treatment with natamycin enhanced relative conductivity of S. sclerotiorum mycelia over time compared with control. The concentration 2 mg L−1 increased the cell membrane permeability of mycelia more than the concentration 1 mg L−1 over 160 min. Moreover, an increase of carbohydrate leakage was observed in the pathogen mycelia incubated with natamycin. The content of methane dicarboxylic aldehyde (MDA) markedly increased at 5 h and the highest MDA content was observed after 20 h. Due to exposure to natamycin, a decrease percentage of catalase activity was observed in pathogen mycelia.

中文翻译：

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游霉素对核盘菌致胡萝卜白霉病的抑制作用

本研究旨在评估游霉素对三种核盘菌分离物的抑制作用，核盘菌是收获后阶段胡萝卜白霉病的病原体。结果表明，游霉素能够显着降低病原体的三个分离株的径向生长和硬化。此外，游霉素显着降低了三个分离株菌核的菌丝生成和产果皮萌发。游霉素浓度与抑制菌丝体生长、硬化和菌核萌发的功效之间存在明显的正相关。在接种病原体前 2.5 小时在胡萝卜根上应用游霉素可显着降低白霉病的发生率。与对照相比，游霉素处理随时间增强了核盘菌菌丝体的相对电导率。在 160 分钟内，浓度 2 mg L-1 比浓度 1 mg L-1 增加的菌丝体细胞膜通透性更多。此外，在与游霉素孵育的病原体菌丝体中观察到碳水化合物泄漏增加。甲烷二甲醛 (MDA) 的含量在 5 小时时显着增加，20 小时后 MDA 含量最高。由于暴露于游霉素，在病原体菌丝体中观察到过氧化氢酶活性的百分比降低。