Plants exposed to stress use the variety of gene regulatory mechanisms to achieve cellular homeostasis, including posttranscriptional regulation of gene expression where microRNAs (miRNAs) play a pivotal role. Since various environmental stress factors such as nanoparticles affect crop productivity and quality, the aim of the present study was to evaluate the genotoxicity level and to estimate miRNA expression level and chlorophyll a level in the magnetite (Fe3O4) nanoparticle-stressed rocket (Eruca sativa Mill.) seedlings grown in hydroponics. Rocket seedlings were exposed to 1 mg/L, 2 mg/L, and 4 mg/L Fe3O4 nanoparticles, and after 5 weeks, seed germination rate, root-shoot elongation, genotoxicity, chlorophyll a, and miRNA expression levels were evaluated. The obtained results indicated that 1 mg/L, 2 mg/L, and 4 mg/L concentrations of Fe3O4 nanoparticles induce low genotoxicity and have a positive effect on the growth and development of rocket seedlings and that nanoparticles may improve the ability of plants to stand against environmental stresses.

A large number of studies have explored the effects of various nanoparticles (NPs) on different economically important plant species. In this study, yellow medick plants were grown for five weeks using hydroponics with the addition of Fe 3 O 4 NPs at 1, 2 and 4 mg/L. Plant morphology, chlorophyll a, genotoxicity and expression of miR159c, one of the most important plant miRNA that is involved in plant response to fungal infections, were investigated. The results indicated that Fe 3 O 4 NPs significantly increased plant root length (9%-32%), chlorophyll a fluorescence (1.94-2.8fold), miRNA expression (0.31-0.42-fold), induced genotoxicity and reduced genome stability (12.5%-13.3%), compared to those of the control. The study demonstrated that Fe 3 O 4 NPs simultaneously induce genome instability in yellow medick and increase expression of miR159c. Therefore, Fe 3 O 4 NPs can be used to increase plant resistance to fungal diseases, such as powdery mildew.

Development of nanotechnology leads to the increasing release of nanoparticles in the environment that results in accumulation of different NPs in living organisms including plants. This can lead to serious changes in plant cultures which leads to genotoxicity. The aims of the present study were to detect if iron oxide NPs pass through the flax cell wall, to compare callus morphology, and to estimate the genotoxicity in Linum usitatissimum L. callus cultures induced by different concentrations of Fe 3 O 4 nanoparticles. Two parallel experiments were performed: experiment A, where flax explants were grown on medium supplemented with 0.5 mg/l, 1 mg/l, and 1.5 mg/l Fe 3 O 4 NPs for callus culture obtaining, and experiment B, where calluses obtained from basal MS medium were transported into medium supplemented with concentrations of NPs identical to experiment A. Obtained results demonstrate similarly in both experiments that 25 nm Fe 3 O 4 NPs pass into callus cells and induce low toxicity level in the callus cultures. Nevertheless, calluses from experiment A showed 100% embryogenesis in comparison with experiment B where 100% rhizogenesis was noticed. It could be associated with different stress levels and adaptation time for explants and calluses that were transported into medium with Fe 3 O 4 NPs supplementation.

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Zinc oxide nanoparticles are one of the most commonly engineered nanomaterials and necessarily enter the environment because of the large quantities produced and their widespread application. Understanding the impacts of nanoparticles on plant growth and development is crucial for the assessment of probable environmental risks to food safety and human health, because plants are a fundamental living component of the ecosystem and the most important source in the human food chain. The objective of this study was to examine the impact of different concentrations of zinc oxide nanoparticles on barley Hordeum vulgare L. seed germination, seedling morphology, root cell viability, stress level, genotoxicity, and expression of miRNAs. The results demonstrate that zinc oxide nanoparticles enhance barley seed germination, shoot/root elongation, and H2O2 stress level and decrease root cell viability and genomic template stability and up- and downregulated miRNAs in barley seedlings.