Changes inArabidopsis thalianaGene Expression in Response to Silver Nanoparticles and Silver Ions

Abstract

The release of silver nanoparticles (AgNPs) in the environment has raised concerns about their effects on living organisms, including plants. In this study, changes in gene expression in Arabidopsis thaliana exposed to polyvinylpyrrolidone-coated AgNPs and silver ions (Ag(+)) were analyzed using Affymetrix expression microarrays. Exposure to 5 mg/L AgNPs (20 nm) for 10 days resulted in upregulation of 286 genes and downregulation of 81 genes by reference to nonexposed plants. Exposure to 5 mg/L Ag(+) for 10 days resulted in upregulation of 84 genes and downregulation of 53 genes by reference to nonexposed plants. Many genes differentially expressed by AgNPs and Ag(+) were found to be involved in the response of plants to various stresses: upregulated genes were primarily associated with the response to metals and oxidative stress (e.g., vacuolar cation/proton exchanger, superoxide dismutase, cytochrome P450-dependent oxidase, and peroxidase), while downregulated genes were more associated with response to pathogens and hormonal stimuli [e.g., auxin-regulated gene involved in organ size (ARGOS), ethylene signaling pathway, and systemic acquired resistance (SAR) against fungi and bacteria]. A significant overlap was observed between genes differentially expressed in response to AgNPs and Ag(+) (13 and 21% of total up- and downregulated genes, respectively), suggesting that AgNP-induced stress originates partly from silver toxicity and partly from nanoparticle-specific effects. Three highly upregulated genes in the presence of AgNPs, but not Ag(+), belong to the thalianol biosynthetic pathway, which is thought to be involved in the plant defense system. Results from this study provide insights into the molecular mechanisms of the response of plants to AgNPs and Ag(+).

Influence of Silver Nano-particles on the Salt Resistance of Tomato (Solanum lycopersicum) during Germination

“…AgNPs have been implicated in agriculture for improving crops. There are many reports indicating that appropriate concentrations of AgNPs play an important role in enhancing seed germination (Barrena et al, 2009;Shelar and Chavan, 2015), plant growth (Salama, 2012;Sharma et al, 2012;Kaveh et al, 2013;Vannini et al, 2013) and improving photosynthetic quantum efficiency and chlorophyll content (Sharma et al, 2012). AgNPs are also used as antimicrobial agents to manage plant diseases (Lamsal et al, 2011).…”

Effect of Silver Nanoparticles on Salt Tolerancy of Tomato Trans-plants (Solanum lycopersicom,L. Mill.)

“…AgNPs have been implicated in agriculture for improving crops. There are many reports indicating that appropriate concentrations of AgNPs play an important role in plant growth (Kaveh et al, 2013;Salama, 2012;Sharma et al, 2012;Vannini et al, 2013) and improving photosynthetic quantum efficiency and chlorophyll content (Hatami and Ghorbanpour, 2013;Sharma et al, 2012). AgNPs are also used as antimicrobial agents to manage plant diseases (Lamsal et al, 2011).…”

Expression profiling of certain MADS-box genes in Arabidopsis thaliana plant treated with silver nanoparticles

“…Recent studies have reported that the plant response to AgNPs results in either enhancement or inhibition of growth depending on AgNP dosage. Of serial concentrations, exposure to specific concentrations of AgNPs could enhance plant growth compared with non-exposed plants, while higher and lower concentrations negatively affect plant growth (Kaveh et al 2013;Qian et al 2013). Of the tested AgNP concentrations (25, 50, 100, 200 and 400 ppm), 50 ppm was the optimal doi: 10.17221/130/2015-CJGPB treatment for eliciting a growth response in Brassica juncea seedlings.…”

“…Recent studies suggested that AgNPs might be beneficial for enhancement of crops such as common bean, maize, castor, watermelon and zucchini (Salama 2012;Yasur & Rani 2013;Almutairi & Alharbi 2015). There are many reports indicating that the appropriate concentrations of AgNPs have an important role in enhancing seed germination (Barrena et al 2009;Savithramma et al 2012) and plant growth (Sharma et al 2012;Kaveh et al 2013). Agricultural researches have sought to ensure that using nanomaterials in increasing the crop productivity is safe and effective.…”