Department of Plant Protection, College of Plant Protection, Hunan Agricultural University, Changsha, China.
Department of Plant Protection, College of Plant Protection, Hunan Agricultural University, Changsha, China.
Pestic Biochem Physiol. 2018 May;147:32-39. doi: 10.1016/j.pestbp.2017.10.006. Epub 2017 Oct 24.
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 (EC) of 9.0934μg/mL. The mycelia of R. solani were then exposed to 18.18μg/mL (2EC) 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.
本研究旨在探索吩嗪-1-甲酰胺（PCN）对立枯丝核菌的作用，并阐明其作用机制。采用生长速率法测定 PCN 对立枯丝核菌的毒性。结果表明，PCN 对立枯丝核菌的抑制作用具有浓度依赖性，其 50%有效浓度（EC）为 9.0934μg/mL。然后用 18.18μg/mL（2EC）PCN 处理立枯丝核菌菌丝。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 对立枯丝核菌菌丝形态和超微结构的影响。经 PCN 处理后，光学显微镜观察发现菌丝扭曲，分支菌丝生长，但分支后主菌丝不生长，菌丝根有空泡增多；SEM 观察发现菌丝局部肿胀，显著度明显降低；TEM 观察发现细胞壁变薄变形，线粒体消失，隔膜扭曲，大部分细胞器难以分辨，而对照中所有细胞器均可清晰观察到。然后，我们使用实时定量 PCR 和酶活性试剂盒进一步探讨 PCN 对细胞壁和线粒体的影响。生理生化结果表明，细胞壁和线粒体均为 PCN 的作用靶点。PCN 抑制几丁质合成酶和线粒体电子传递链复合物 I 的活性。分子实验表明，PCN 通过抑制几丁质合成酶基因的表达水平来控制立枯丝核菌菌丝的生长。未来对 PCN 的研究应探讨其对代谢途径的影响，从而有助于新型农药的潜在开发。
