Institute of Crop Protection, Guizhou University, Guiyang 550025, PR China; College of Agriculture, Guizhou University, Guiyang 550025, PR China.
Institute of Crop Protection, Guizhou University, Guiyang 550025, PR China; College of Agriculture, Guizhou University, Guiyang 550025, PR China; The Provincial Key Laboratory for Agricultural Pest Management in Mountainous Region, Guiyang 550025, PR China.
Pestic Biochem Physiol. 2023 Nov;196:105623. doi: 10.1016/j.pestbp.2023.105623. Epub 2023 Sep 15.
Dendrobium officinale Kimura et Migo is a traditional Chinese herbal medicinal plant. However, the frequent occurrence of soft rot disease (SRD) is one of the most harmful diseases in D. officinale production in recent years, which can seriously affect its yield and quality. In this study, the major pathogenic fungus (SR-1) was isolated from D. officinale with typical symptoms of SRD, and was identified as Fusarium oxysporum through morphological and molecular identification. The biological activities of five natural products were determined against F. oxysporum using a mycelial growth inhibition assay. The results showed that osthole had the highest antifungal activity against F. oxysporum, with an EC value of 6.40 mg/L. Scanning electron microscopy (SEM) showed that osthole caused F. oxysporum mycelia to shrink and deform. Transmission electron microscopy (TEM) showed that the organelles were blurred and the cell wall was thickened in the presence of osthole. The sensitivity of F. oxysporum to calcofluor white (CFW) staining was significantly enhanced by osthole. Relative conductivity measurements and propidium iodide (PI) observation revealed that osthole had no significant effect on the cell membrane. Further experiments showed that the activity of chitinase and β-1,3-glucanase were decreased, and expression levels of chitinase and β-1,3-glucanase related genes were significantly down-regulated after treatment with osthole. In conclusion, osthole disrupted the cell wall integrity and dynamic balance of F. oxysporum, thereby inhibiting normal mycelial growth.
铁皮石斛是一种传统的中草药植物。然而，近年来，软腐病（SRD）的频繁发生是铁皮石斛生产中最具危害性的疾病之一，它会严重影响其产量和质量。本研究从表现出典型软腐病症状的铁皮石斛中分离出主要病原菌（SR-1），并通过形态学和分子鉴定将其鉴定为尖孢镰刀菌（Fusarium oxysporum）。采用菌丝生长抑制法测定了 5 种天然产物对 F. oxysporum 的生物活性。结果表明，蛇床子素对 F. oxysporum 的抑菌活性最高，EC 值为 6.40mg/L。扫描电子显微镜（SEM）显示蛇床子素导致 F. oxysporum 菌丝收缩变形。透射电子显微镜（TEM）显示，在存在蛇床子素的情况下，细胞器模糊，细胞壁增厚。蛇床子素显著增强了 F. oxysporum 对荧光增白剂（CFW）染色的敏感性。相对电导率测量和碘化丙啶（PI）观察表明，蛇床子素对细胞膜没有明显影响。进一步的实验表明，几丁质酶和β-1,3-葡聚糖酶的活性降低，并且在处理后，几丁质酶和β-1,3-葡聚糖酶相关基因的表达水平显著下调。综上所述，蛇床子素破坏了 F. oxysporum 的细胞壁完整性和动态平衡，从而抑制了正常菌丝的生长。
