Growth-Promoting Gold Nanoparticles Decrease Stress Responses in Arabidopsis Seedlings

Abstract

The global economic success of man-made nanoscale materials has led to a higher production rate and diversification of emission sources in the environment. For these reasons, novel nanosafety approaches to assess the environmental impact of engineered nanomaterials are required. While studying the potential toxicity of metal nanoparticles (NPs), we realized that gold nanoparticles (AuNPs) have a growth-promoting rather than a stress-inducing effect. In this study we established stable short- and long-term exposition systems for testing plant responses to NPs. Exposure of plants to moderate concentrations of AuNPs resulted in enhanced growth of the plants with longer primary roots, more and longer lateral roots and increased rosette diameter, and reduced oxidative stress responses elicited by the immune-stimulatory PAMP flg22. Our data did not reveal any detrimental effects of AuNPs on plants but clearly showed positive effects on growth, presumably by their protective influence on oxidative stress responses. Differential transcriptomics and proteomics analyses revealed that oxidative stress responses are downregulated whereas growth-promoting genes/proteins are upregulated. These omics datasets after AuNP exposure can now be exploited to study the underlying molecular mechanisms of AuNP-induced growth-promotion.

Charged Gold Nanoparticles Promote In Vitro Proliferation in Nardostachys jatamansi by Differentially Regulating Chlorophyll Content, Hormone Concentration, and Antioxidant Activity

“…Furthermore, after 10 weeks of in vitro culture of Lamprocapnos spectabilis , treatment of AuNPs increased the shoot number, but reduced rooting [ 34 ]. Moreover, 10 mg/L of citrate-AuNPs were previously shown to influence all of the growth parameters of Arabidopsis [ 35 ]. In our findings, we observed that all the growth parameters as well as the physiological and biochemical activities were enhanced at an optimum concentration of 60 µM of citrate-AuNPs and 40 µM of CTAB-AuNPs, whereas negative regulation was observed at a 10 µM concentration of citrate-AuNPs.…”

“…A higher absorption of nitrate further improved the synthesis of phenolic compounds [ 45 , 46 ]. Citrate-coated gold nanoparticles positively influenced all of the growth parameters of Arabidopsis at a concentration of 10 mg/L [ 35 ].…”

Recent Advances in Metal-Based Nanoparticle-Mediated Biological Effects in Arabidopsis thaliana: A Mini Review

“…Growth potential, seed germination, biomass and leaf surface area are the commonly used parameters to assess morphological changes in plants and phytotoxicity [74][75][76][77][78]. Kaveh et al found that exposure to Ag NPs (from 5 to 20 mg/L) resulted in reduced biomass of Arabidopsis, while Ag NPs at concentrations of 50 mg/L and 60 mg/L had a positive effect on root growth.…”

Potassium Chloroaurate-Mediated In Vitro Synthesis of Gold Nanoparticles Improved Root Growth by Crosstalk with Sucrose and Nutrient-Dependent Auxin Homeostasis in Arabidopsis thaliana

“…Arabidopsis thaliana (Arabidopsis) was the first plant whose genome was sequenced and is a popular model plant species [9][10][11]. Therefore, Arabidopsis has been used to decipher various morphophysiological and molecular responses that are induced during the in planta synthesis of AuNPs [12][13][14][15][16]. Arabidopsis root system architecture (RSA) represents the spatial configuration of primary and lateral roots and plays a pivotal role in the acquisition of nutrients and water [17].…”