Metabolomics of wheat grains generationally-exposed to cerium oxide nanoparticles.

This study investigated changes in metabolite compositions over three generation exposure of wheat (Triticum aestivum) to cerium oxide nanoparticles (CeO2-NPs) in low or high nitrogen soil. The goal was to determine if CeO2-NPs affects grains/seeds quality across generational exposure. Seeds from plants exposed for two generations to 0 or 500 mg CeO2-NPs per kg soil treatment were cultivated for third year in low or high nitrogen soil amended with 0 or 500 mg CeO2-NPs per kg soil. Metabolomics identified 180 metabolites. Multivariate analysis showed that continuous generational exposure to CeO2-NPs altered 18 and 11 metabolites in low N and high N grains, respectively. Interestingly, DNA/RNA metabolites such as thymidine, uracil, guanosine, deoxyguanosine, adenosine monophosphate were affected; a finding that has not been observed on DNA/RNA metabolites of plants exposed to nanoparticles. Nicotianamine, a metabolite playing crucial role in Fe storage in grains, decreased by 33% in grains continuously exposed for three generations to CeO2-NPs at high N soil. Notably, these grains also exhibited a concomitant decrease of 13-16% in Fe concentration. Together these changes suggest alterations in grain quality or implications in ecosystem processes (i.e., productivity, nutrient cycling, ecosystem stability) of progeny plants generationally-exposed to CeO2-NPs.

Wheat exposure to cerium oxide nanoparticles over three generations reveals transmissible changes in nutrition, biochemical pools, and response to soil N.

This study investigated the effects of third generation exposure to cerium oxide nanoparticles (CeO2-NPs) on biomass, elemental and 15N uptake, and fatty acid contents of wheat (Triticum aestivum). At low or high nitrogen treatment (48 or 112 mg N), seeds exposed for two generations to 0 or 500 mg CeO2-NPs per kg soil treatment were cultivated for third year in soil amended with 0 or 500 mg CeO2-NPs per kg soil. The results showed that parental and current exposures to CeO2-NPs increased the root biomass in daughter plants with greater magnitude of increase at low N than high N. When wheat received CeO2-NPs in year 3, root elemental contents increased primarily at low N, suggesting an important role of soil N availability in altering root nutrient acquisition. The δ15N ratios, previously shown to be altered by CeO2-NPs, were only affected by current and not parental exposure, indicating effects on N uptake and/or metabolism are not transferred from one generation to the next. Seed fatty acid composition was also influenced both by prior and current exposure to CeO2-NPs. The results suggest that risk assessments of NP exposure may need to include longer-term, transgenerational effects on growth and grain quality of agronomic crops.