The purpose of this research was to explore the effect of phenazine-1-carboxamide (PCN) on Rhizoctonia solani and to elucidate its mechanisms of action. The toxicity of PCN to R. solani was measured using a growth rate method. The results indicated that PCN inhibited R. solani with a 50% effective concentration (EC50) of 9.0934μg/mL. The mycelia of R. solani were then exposed to 18.18μg/mL (2EC50) of PCN. Optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to observe the effects of PCN on mycelial morphology and ultrastructure. Following the PCN treatment, the optical microscopy observations revealed that the mycelia appeared twisted; the branching mycelia grew, but the main mycelia did not grow following branching; and the mycelial roots possessed more vacuoles. SEM observations revealed that the mycelia were locally swollen and exhibited a sharp decrease in prominence. TEM observations showed that the cell wall became thin and deformed; the mitochondria disappeared; the septum twisted; and most of the organelles were difficult to discern. Conversely, all of the organelles could be clearly observed in the control. We then used real-time quantitative PCR and an enzyme activity testing kit to further explore the effects of PCN on the cell wall and mitochondria. Physiological and biochemical results demonstrated that both the cell wall and mitochondria constitute are PCN targets. PCN inhibited the activities of chitin synthetase and complex I of the mitochondria electron transport chain. Molecular experiments demonstrated that PCN controlled the growth of R. solani mycelia by inhibiting the expression level of chitin synthetase genes. Future research on PCN should investigate its influence on metabolic pathways, thereby aiding in the potential development of novel pesticides.

中文翻译：

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吩嗪-1-甲酰胺对立枯丝核菌菌丝形态和超微结构的影响及抑制机制

本研究的目的是探索吩嗪-1-甲酰胺 (PCN) 对立枯丝核菌的影响并阐明其作用机制。PCN 对 R. solani 的毒性使用生长速率方法测量。结果表明PCN以9.0934μg/mL的50%有效浓度(EC50)抑制R. solani。然后将茄病菌菌丝体暴露于 18.18μg/mL (2EC50) 的 PCN。采用光学显微镜、扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察PCN对菌丝形态和超微结构的影响。PCN处理后，光学显微镜观察显示菌丝体出现扭曲；分枝菌丝生长，但主菌丝分枝后不生长；菌丝根有更多的液泡。SEM 观察显示，菌丝体局部肿胀，突出度急剧下降。TEM观察显示细胞壁变薄变形；线粒体消失了；隔膜扭曲；大多数细胞器都难以辨别。相反，在对照中可以清楚地观察到所有细胞器。然后我们使用实时定量 PCR 和酶活性检测试剂盒进一步探索 PCN 对细胞壁和线粒体的影响。生理和生化结果表明，细胞壁和线粒体构成都是 PCN 靶点。PCN抑制线粒体电子传递链的几丁质合成酶和复合物I的活性。分子实验表明 PCN 控制了 R 的生长。solani菌丝体通过抑制几丁质合成酶基因的表达水平。未来对 PCN 的研究应调查其对代谢途径的影响，从而有助于新型农药的潜在开发。