State Key Laboratory of Pollution Control and Resource Reuse, School of Environment , Nanjing University , Nanjing 210023 , China.
Chemistry Department , The University of Texas at El Paso , 500 West University Avenue, El Paso , Texas 79968 , United States.
Environ Sci Technol. 2018 Jul 17;52(14):8016-8026. doi: 10.1021/acs.est.8b02440. Epub 2018 Jun 28.
Due to their well-known antifungal activity, the intentional use of silver nanoparticles (AgNPs) as sustainable nanofungicides is expected to increase in agriculture. However, the impacts of AgNPs on plants must be critically evaluated to guarantee their safe use in food production. In this study, 4-week-old cucumber ( Cucumis sativus) plants received a foliar application of AgNPs (4 or 40 mg/plant) or Ag (0.04 or 0.4 mg/plant) for 7 days. Gas chromatography-mass spectrometry (GC-MS)=based nontarget metabolomics enabled the identification and quantification of 268 metabolites in cucumber leaves. Multivariate analysis revealed that all the treatments significantly altered the metabolite profile. Exposure to AgNPs resulted in metabolic reprogramming, including activation of antioxidant defense systems (upregulation of phenolic compounds) and downregulation of photosynthesis (upregulation of phytol). Additionally, AgNPs enhanced respiration (upregulation of tricarboxylic acid cycle intermediates), inhibited photorespiration (downregulation of glycine/serine ratio), altered membrane properties (upregulation of pentadecanoic and arachidonic acids, downregulation of linoleic and linolenic acids), and reduced inorganic nitrogen fixation (downregulation of glutamine and asparagine). Although Ag ions induced some of the same metabolic changes, alterations in the levels of carbazole, lactulose, raffinose, citraconic acid, lactamide, acetanilide, and p-benzoquinone were AgNP-specific. The results of this study offer new insight into the molecular mechanisms by which cucumber responds to AgNP exposure and provide important information to support the sustainable use of AgNPs in agriculture.
由于其众所周知的抗真菌活性，将银纳米粒子（AgNPs）有意用作可持续纳米杀菌剂预计将在农业中增加。然而，必须严格评估 AgNPs 对植物的影响，以保证其在食品生产中的安全使用。在这项研究中，4 周龄的黄瓜（ Cucumis sativus）植物接受了叶面喷施 AgNPs（4 或 40 mg/株）或 Ag（0.04 或 0.4 mg/株）7 天。基于气相色谱-质谱联用（GC-MS）的非靶向代谢组学能够鉴定和定量黄瓜叶片中的 268 种代谢物。多变量分析显示，所有处理均显著改变了代谢物图谱。暴露于 AgNPs 导致代谢重编程，包括抗氧化防御系统的激活（酚类化合物的上调）和光合作用的下调（质体的下调）。此外，AgNPs 增强了呼吸作用（三羧酸循环中间体的上调），抑制了光呼吸（甘氨酸/丝氨酸比的下调），改变了膜性质（十五烷酸和花生四烯酸的上调，亚油酸和亚麻酸的下调），并减少了无机氮固定（谷氨酰胺和天冬酰胺的下调）。尽管 Ag 离子诱导了一些相同的代谢变化，但咔唑、乳果糖、棉子糖、柠康酸、乳酰胺、乙酰苯胺和对苯醌的水平变化是 AgNP 特异性的。本研究的结果提供了黄瓜对 AgNP 暴露反应的分子机制的新见解，并为支持 AgNPs 在农业中的可持续使用提供了重要信息。
