Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, 5375171379, Tabriz, Iran.
Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, 5375171379, Tabriz, Iran.
J Invertebr Pathol. 2022 May;190:107749. doi: 10.1016/j.jip.2022.107749. Epub 2022 Mar 10.
Entomopathogenic fungi produce extracellular enzymes to facilitate host infection, and these can also reduce metal ions to produce nanoparticles. In the present study, three isolates of Beauveria bassiana (JS1, JS2 and KA75) and one isolate of Metarhizium anisopliae (TT1) were evaluated for their ability to biosynthesize silver nanoparticles (AgNPs). In general, the best yields and smallest NP sizes were obtained at 60 °C and pH 7.0. Nanoparticle properties were studied using UV-visible spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. Biosynthesized AgNPs ranged from 23 to 101 nm across, the smallest being produced by KA75, and the largest by TT1. UV-visible spectroscopy confirmed peak absorption of AgNPs in the range of 420-454 nm. AgNP antibacterial activity was highest against the gram-negative bacteria Pectobacterium carotovorum and Erwinia amylovora, and lower against the gram-positive Bacillus sp. AF1. JS1-AgNPs caused the greatest growth restriction of P. carotovorum at a concentration of 75 µL/mL at lower OD (0.25). Smaller AgNPs generally had better antifungal activities against B. bassiana, M. anisopliae, and the plant-pathogenic Rhizoctonia solani. Complete inhibition of vegetative growth of the JS2 fungus was obtained with TT1-synthesized AgNPs at 15 µL/mL, a control level similar to half the field rate of benomyl. Generally, fungal sporulation was more inhibited than vegetative growth, and all AgNPs showed good compatibility with the fungi at low concentrations. We conclude that AgNPs mycosynthesized by these entomopathogens have promising antibacterial and antifungal properties with potential for various applications.
昆虫病原真菌产生细胞外酶以促进宿主感染，这些酶还可以还原金属离子产生纳米颗粒。本研究评估了 3 株球孢白僵菌（JS1、JS2 和 KA75）和 1 株金龟子绿僵菌（TT1）的生物合成银纳米颗粒（AgNPs）的能力。一般来说，在 60°C 和 pH7.0 下获得了最佳产量和最小的 NP 尺寸。使用紫外-可见分光光度法、傅里叶变换红外光谱法和扫描电子显微镜研究了纳米颗粒的性质。生物合成的 AgNPs 的粒径范围为 23-101nm，最小的由 KA75 产生，最大的由 TT1 产生。紫外-可见光谱证实了 AgNPs 在 420-454nm 范围内的峰值吸收。AgNP 的抗菌活性对革兰氏阴性菌果胶杆菌和梨火疫病菌最高，对革兰氏阳性菌芽孢杆菌 AF1 较低。JS1-AgNPs 在较低 OD（0.25）时，在 75µL/mL 浓度下对 P. carotovorum 的生长抑制最大。一般来说，较小的 AgNPs 对球孢白僵菌、绿僵菌和植物病原菌立枯丝核菌具有更好的抗真菌活性。在 15µL/mL 时，TT1 合成的 AgNPs 完全抑制了 JS2 真菌的营养生长，这一控制水平与苯菌灵田间用量的一半相似。一般来说，真菌的营养生长比孢子形成受到更强烈的抑制，而且所有 AgNPs 在低浓度下与真菌具有良好的相容性。我们得出结论，这些昆虫病原真菌生物合成的 AgNPs 具有有前途的抗菌和抗真菌特性，具有各种应用的潜力。
