Oxidative stress-induced toxicity of CuO nanoparticles and related toxicogenomic responses in Arabidopsis thaliana

Abstract

Microarray analysis of toxicogenomic effects of CuO NPs on Arabidopsis thaliana was conducted. Arabidopsis growth was significantly inhibited by CuO NPs (10 and 20 mg/L). CuO NPs (10 and 20 mg/L) caused significant root damage after short-time (0-2 h) exposure while their corresponding Cu(2+) ions (0.80 and 1.35 mg/L) did not show any root damage. After longer exposure times (1 and 2 days), Cu(2+) ions induced obvious root damage, indicating that released Cu(2+) ions from CuO NPs contributed partial toxicity during CuO NPs exposure. After CuO NPs (10 mg/L) exposure for 2 h, reactive oxygen species (ROS) generation in root tips was much higher than that in the corresponding Cu(2+) ions (0.8 mg/L) treatment. The gene ontology categories identified from microarray analysis showed that CuO NPs (10 mg/L) caused 1658 differentially expressed genes (p < 0.01, fold change>3). Of these, 1035 and 623 genes were up-regulated and down-regulated, respectively. 47 genes among all the up-regulated genes were response to oxidative stress, in which 19 genes were also related to "response to abiotic stimulus" and 12 genes were involved in the phenylpropanoid biosynthesis of the KEGG metabolic pathway. The expression of all the selected genes (RHL41, MSRB7, BCB, PRXCA, and MC8) measured using quantitative RT-PCR was consistent with the microarray analysis. CuO NPs contributed much stronger up-regulation of oxidative stress-related genes than the corresponding Cu(2+) ions.

The Role of Nanotechnology in the Fortification of Plant Nutrients and Improvement of Crop Production

“…ZnO-NPs has been reported to affect the soil microbial metabolism and reduce the numbers of the nutrient fixing bacteria such as the azotobacter, and P-and K-solubilizing bacteria [130,162]. CuO NPs are also reported to inhibit the root growth of wheat plants [163,164]. Copper nanoparticles can affect the photosynthetic, respiratory and growth processes of the plant at higher concentration and would pose dangers on humans when such crops are consumed.…”

Can CuO nanoparticles lead to epigenetic regulation of antioxidant enzyme system?

“…Hence it can be reasoned that the excess production of ROS may result in secretion of EGF which in turn results in TNF production that prompts early production of IL-8 a change in the physiology of the cell namely, a decrease in oxygen levels due to ischemia/hypoxia will cause late induction of IL-8 that leads to activation of NF-KB pathway ( Table 4). The released copper ionic species is also considered to be the cause of CuO NPs-induced toxicity (Tang et al, 2016). Surface-released copper ions primarily affect cell membrane integrity.…”

Interactions between nanoparticles and plants: phytotoxicity and defense mechanisms

“…Growth inhibition was observed when Bacillus thuringiensis (Bt)-transgenic cotton was exposed to SiO 2 NPs (Le Van et al 2014). When wheat plants were grown in a sand matrix, CuO NPs inhibited their growth and changed the structure of the roots (Dimkpa et al 2012;Tang et al 2016). Shaw and Hossain (2013) showed that CuO NPs significantly reduced the fresh weights and root length of Arabidopsis seedlings, and the germination rate and biomass of rice seeds.…”