Toxicity of silver nanoparticles to Arabidopsis: Inhibition of root gravitropism by interfering with auxin pathway

Abstract

Impacts of polyvinylpyrrolidine-coated silver nanoparticles (AgNPs) on root gravitropism in Arabidopsis thaliana were investigated at the physiological, cellular, and molecular levels. Our results showed that AgNPs were taken up by the root and primarily localized at the cell wall and intercellular spaces. Root gravitropism was inhibited by exposure to AgNPs, and the inhibition in root gravitropism caused by exposure to AgNPs exhibited a dose-response relationship. Auxin accumulation was reduced in the root tips because of exposure to AgNPs. However, increased indole-3-acetic acid level could not rescue the inhibition of root gravitropism. Real-time polymerase chain reaction showed significant downregulation of expression of auxin receptor-related genes, which is the TIR1/AFB family of F-box proteins including AFB1, AFB2, AFB3, AFB5, and TIR1. Therefore, the present study suggests that AgNPs have toxicity to the model plant A. thaliana as shown by inhibition of root gravitropism along with a reduction in auxin accumulation and expression of auxin receptors. Environ Toxicol Chem 2017;36:2773-2780. © 2017 SETAC.

Impacts of Silver Nanoparticles on Plants: A Focus on the Phytotoxicity and Underlying Mechanism

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Surface Coating-Modulated Phytotoxic Responses of Silver Nanoparticles in Plants and Freshwater Green Algae

“…In addition to aforementioned effects, AgNPs can also have an effect associated with hormonal signaling. Most of the auxin-receptor related genes were downregulated in A. thaliana exposed to AgNP-PVP [ 186 ], while Ag 2 S-NPs upregulated genes involved in ethylene signaling pathway in wheat and cucumber [ 184 ]. Both hormones are important for plant growth regulation.…”

Colloidal Silver Nanoparticles Enhance Bulb Yield and Alleviate the Adverse Effect of Saline Stress on Lily Plants

“…The beneficial effect of nanosilver at a concentration of 4 ppm added to the in vitro medium on bulblet formation from bulb scales was also demonstrated by Gioi et al (2019), who propagated the OT lily 'Sorbonne'. The effect of AgNPs on the process of bulb formation may be related to the effect of AgNPs on plant hormones (Sun et al, 2017). While the biostimulatory effects of AgNPs on plants are increasingly understood, their mechanism remains unexplained.…”