Assessment of silver nanoparticle-induced physiological and molecular changes in Arabidopsis thaliana.
In this study, the effect of silver nanoparticles and silver ions on Arabidopsis thaliana was investigated at physiological and molecular levels. The seedlings were grown in sublethal concentrations of silver nanoparticles and silver ions (0.2, 0.5, and 1 mg/L) in 1/4 Hoagland's medium for 14 days under submerged hydroponic conditions. Significantly higher reduction in the total chlorophyll and increase in anthocyanin content were observed after exposure to 0.5 and 1 mg/L silver nanoparticles as compared to similar concentrations of silver ions. Lipid peroxidation increased significantly after exposure to 0.2, 0.5, and 1 mg/L of silver nanoparticles and 0.5 and 1 mg/L of silver ions. Qualitative analysis with dichloro-dihydro-fluorescein diacetate and rhodamine 123 fluorescence showed a dose-dependent increase in reactive oxygen species production and changes in mitochondrial membrane potential in the roots of seedlings exposed to different concentrations of silver nanoparticles. Real-time PCR analysis showed significant upregulation in the expression of sulfur assimilation, glutathione biosynthesis, glutathione S-transferase, and glutathione reductase genes upon exposure to silver nanoparticles as compared with silver ions. Overall, based on the physiological and molecular level responses, it was observed that exposure to silver nanoparticles exerted more toxic response than silver ions in A. thaliana.
Department of Applied Biosciences, College of Life and Environmental Sciences, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, South Korea.
Prakash M Gopalakrishnan
PM
Nair
Ill Min
IM
Chung
D000872:Anthocyanins / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects* / Q000502:physiology*; D002734:Chlorophyll / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005978:Glutathione / Q000235:genetics / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D053768:Metal Nanoparticles / Q000633:toxicity*; D018517:Plant Roots / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012834:Silver / Q000493:pharmacokinetics / Q000633:toxicity*; D013455:Sulfur / Q000378:metabolism
D000872:Anthocyanins; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D012834:Silver; D013455:Sulfur; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D005978:Glutathione