Combined application of plant essential oils (EOs) with known antimicrobial effects and silica nanocapsules with high loading capacity and protection capability of the EOs make them proper candidates for creating environmentally friendly fungicides. In this study, EOs of the Lemongrass (LGO) and Clove (CO) were used against Gaeumannomyces graminis var. tritici (Ggt), a causal agent of take-all disease of wheat. To provide controlled delivery of the EOs, they were encapsulated into mesoporous silica nanoparticles (MSNPs) and then compared to the effects of pure EOs both in- vitro and in- vivo. MSNPs were synthesized via the sol-gel process. Various techniques such as Fourier transform infrared spectroscopy (FTIR), the Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), and UV-Vis spectroscopy were used to evaluate the successful loading of the EOs into the pore of MSNPs. The encapsulation efficiency (EE) was calculated as high as 84.24% for LGO and 80.69% for CO, while loading efficiency (LE) was determined 36% and 29% for LGO and CO, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) displayed spherical shapes and porous structures with average diameters of 50-70 nm. Recognition of the main components of the EOs via gas chromatographic-mass spectrometry (GC-MS) before and after the EO loading, detected eugenol and citral as the most frequent compounds in LGO and CO, respectively. For antifungal test in- vitro, selected concentrations of the pure EOs, EOs loaded in MSNPs (EOs- MSNPs) and Mancozeb ® fungicide based on pre-tests were mixed using potato dextrose agar (PDA). The inhibition percentage (IP) of fungal growth at each concentration, as well as minimum inhibition concentration (MIC) and minimum fungicidal concentrations (MFC) were obtained. The results indicated that antifungal effects in the encapsulated form increased by up to three times. In- vivo, the sterile wheat seeds were treated with pure EOs, EOs-MSNPs, and mancozeb at MFC concentration. Also, in order to keep on the EOs-MSNPs around the seeds, sodium alginate was used. The consequences of in- vivo experiments indicated that rate of disease control in presence of EOs-MSNPs and mancozeb was the same (~70%) and higher than pure EOs (LGO: 57.44%, CO: 49%). Also, improving the growth parameters in wheat plant, the covering of the EOs-MSNPs in alginate, had better control (84%) than that of EOs-MSNPs alone. Further, the release kinetics studies showed a gradual release of LGO and CO from MSNPs for four weeks in water and for five weeks in the soil-plant system. To the best of our knowledge, this is the first report of the control effect of LGO, CO, and their nanocapsule in MSNPs against the take-all disease of wheat. These results showed that the EOs-MSNPs can be a safe product for the efficient control of take-all disease in wheat crop.

中文翻译：

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包封在介孔二氧化硅纳米粒子中的柠檬草和丁香油对小麦通吃病的抗真菌活性

将具有已知抗菌作用的植物精油 (EO) 与具有高负载能力和 EO 保护能力的二氧化硅纳米胶囊相结合，使其成为创造环境友好型杀菌剂的合适候选者。在这项研究中，柠檬草 (LGO) 和丁香 (CO) 的 EO 被用于对抗 Gaeumannomyces graminis var。小麦（Ggt），小麦全病的病原体。为了提供 EO 的受控递送，将它们封装到介孔二氧化硅纳米粒子 (MSNP) 中，然后与纯 EO 的体外和体内效果进行比较。MSNPs 是通过溶胶-凝胶法合成的。各种技术，例如傅里叶变换红外光谱 (FTIR)、Brunauer-Emmett-Teller (BET)、热重分析 (TGA)、和紫外-可见光谱用于评估 EOs 成功加载到 MSNPs 的孔中。经计算，LGO 的封装效率 (EE) 高达 84.24%，CO 的封装效率高达 80.69%，而 LGO 和 CO 的负载效率 (LE) 分别为 36% 和 29%。扫描电子显微镜 (SEM) 和透射电子显微镜 (TEM) 显示平均直径为 50-70 nm 的球形和多孔结构。在 EO 加载前后通过气相色谱-质谱联用 (GC-MS) 识别 EO 的主要成分，检测到丁香酚和柠檬醛分别是 LGO 和 CO 中最常见的化合物。对于体外抗真菌测试，使用马铃薯葡萄糖琼脂 (PDA) 将选定浓度的纯 EO、加载在 MSNP 中的 EO (EOs-MSNP) 和基于预测试的 Mancozeb ® 杀真菌剂混合。获得了每个浓度下真菌生长的抑制百分比（IP），以及最小抑制浓度（MIC）和最小杀真菌浓度（MFC）。结果表明，封装形式的抗真菌作用增加了三倍。在体内，无菌小麦种子用纯 EO、EO-MSNP 和 MFC 浓度的代森锰锌处理。此外，为了保持种子周围的 EOs-MSNP，使用了海藻酸钠。体内实验的结果表明，存在 EOs-MSNPs 和代森锰锌时的疾病控制率相同（~70%）并且高于纯 EOs（LGO：57.44%，CO：49%）。此外，改善小麦植株的生长参数，藻酸盐中 EOs-MSNPs 的覆盖比单独的 EOs-MSNPs 具有更好的控制（84%）。更多，释放动力学研究表明，MSNPs 在水中逐渐释放 LGO 和 CO，持续 4 周，在土壤-植物系统中持续 5 周。据我们所知，这是首次报道了 LGO、CO 及其在 MSNP 中的纳米胶囊对小麦全麦病害的控制作用。这些结果表明，EOs-MSNPs 是一种安全的产品，可有效控制小麦作物的综合病害。