Phytopathogenic fungi infect plants during growth, development, and harvest and their products during postharvest storage and transport. Fungicides are applied indiscriminately to combat these pathogens, posing a serious threat to humans, animals, and the environment. Some filamentous fungi also produce mycotoxins, which pose further problems. In this study we evaluated the antifungal activity of Saussurea lappa root extracts against several potent phytopathogenic fungi (Fusarium solani, F. moniliforme, F. oxysporum, Helminthosporium sativum, and Macrophomina phaseoloni). Various solvent extracts (methanol, ethanol, dichloromethane, ethyl acetate, and water) of the S. lappa root were used. We found that methanol, ethanol, and dichloromethane extracts had potent antifungal activity against all tested isolates. M. phaseolina showed the highest inhibition (89%) with a 5% methanol extract of S. lappa, and severe damage to the morphology and ultrastructure of its cells was also observed. SEM micrographs revealed that cells treated with S. lappa extracts had distorted, peeled, twisted, and shortened mycelium and peeled, completely distorted, and underdeveloped conidia. Moreover, the dichloromethane S. lappa extract (5%) arrested conidial development completely. Similarly, TEM studies showed that treated cells lacked clear demarcations between the cell membrane and cell wall, and had heavy vacuolation, a detached cytoplasm, ruptured and distorted mycelium and conidia, and a clear deposition of electron dense granules on the outer surface. GC-MS and FTIR studies indicated the presence of important bioactive compounds and functional groups in the extracts. Our results indicate that S. lappa roots are a rich source of bioactive compounds that can affect the integrity, stability, and structure of the fungal cell membrane, ultimately leading to cell death. Thus, root extracts could serve as eco-friendly, safe alternatives to the fungicides that are applied at both the harvest and postharvest stages.

中文翻译：

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雪莲根对植物病原真菌的抗真菌作用及形态和超微结构变化

植物致病真菌在生长，发育和收获期间感染植物，在收获后的储存和运输过程中感染植物及其产品。不加选择地使用杀真菌剂来对抗这些病原体，对人类，动物和环境构成严重威胁。一些丝状真菌也会产生霉菌毒素，这会带来进一步的问题。在这项研究中，我们评估了雪莲（Sussurea lappa）根提取物对几种有效的植物病原真菌（镰刀菌（Fusarium solani），念珠菌（F. moniliforme），尖孢镰刀菌（F. oxysporum），杀虫剂（Helminthosporium sativum）和菜豆大单胞菌（Macphophomina phaseoloni）的抗真菌活性。各种溶剂提取的（甲醇，乙醇，二氯甲烷，乙酸乙酯，和水）S.牛蒡使用根。我们发现甲醇，乙醇和二氯甲烷提取物对所有测试的分离物均具有有效的抗真菌活性。用5％的laplap甲醇提取物，菜豆分枝杆菌表现出最高的抑制作用（89％），并且还观察到对其细胞形态和超微结构的严重破坏。扫描电镜显微照片显示，用葡萄球菌提取物处理过的细胞变形，去皮，扭曲，缩短菌丝体，去皮，完全变形且分生孢子不足。此外，二氯甲烷S. lappa提取物（5％）完全阻止了分生孢子的形成。同样，TEM研究表明，处理过的细胞在细胞膜和细胞壁之间缺乏清晰的分界，并且具有严重的空泡化，胞质分离，菌丝体和分生孢子破裂和变形以及电子致密颗粒在外表面的清晰沉积。GC-MS和FTIR研究表明提取物中存在重要的生物活性化合物和官能团。我们的研究结果表明，小号。 拉帕根是生物活性化合物的丰富来源，可影响真菌细胞膜的完整性，稳定性和结构，最终导致细胞死亡。因此，根部提取物可作为在收获和收获后施用的杀菌剂的生态安全替代品。