Functional toxicogenomics of CdS QDs in Arabidopsis thaliana

Nanotechnology is a rapidly growing industry and engineered nanomaterials (NMs) are applied in several areas such as electronics, biomedicine, pharmaceuticals, cosmetics, food production. The scarce knowledge about uptake, interaction with cells is hindering the full application of ENMs, as shown by recent decisions of the European Commission and European Food Safety Authority. The aim of this work was to develop a toxicogenomics approach for risk assessment of NMs, focusing on quantum dots cadmium sulfide nanoparticles (CdS QDs) using Arabidopsis thaliana (L.) Heynh as model system. Two mutant lines of Arabidopsis have been selected as resistant to lethal concentrations of CdS QDs, and the phenotypes and genotypes have been characterized. Global gene expression in the two mutants have been analyzed using Affymetrix GeneChip ATH1, showing differences in induced and repressed genes both in wild type and mutants. Candidates genes found were validated by Real Time PCR. Results obtained from mutant-based and whole-genome approaches in plant could offer a possible hypothesis concerning the tolerance/resistance mechanism in which the CdS QDs are involved. Furthermore results found suggested that CdS QDs and Cd2+ could exploit different pathways of tolerance/resistance. It was also observed a possible epistatic activity by which the up- or down-regulation of one or few genes could lead to a cascade of other genes influenced by the CdS treatments. Therefore, plant-based model systems are able to provide information about genetic and physiologic targets of broad interest also in other organisms related to the risks posed by the exposition and contact with NMs.