Relatively low dosages of CeO2 nanoparticles in the solid medium induce adjustments in secondary metabolism and ionomic balance of bean (Phaseolus vulgaris L.) roots and leaves

Nanoparticles are known to significantly alter plant metabolism in a dose dependent manner, with effects ranging from stimulation to toxicity. The metabolic adjustment and ionomic balance of bean (Phaseolus vulgaris L.) roots and leaves gained from plants grown in a solid medium added with relatively low dosages (0, 25, 50 and 100 mg/L) of CeO2 nanoparticles, was investigated. Ce accumulated in the roots (up to 287.91 mg/kg dry weight) and translocated to aerial parts (up to 2.78% at the highest CeO2 dosage), and ionomic analysis showed that CeO2 nanoparticles interfered with potassium, molybdenum and zinc. Unsupervised hierarchical clustering analysis from metabolomic profiles suggested a dose-dependent and tissue specific metabolic reprogramming induced by nanoparticles. The majority of differential metabolites belonged to flavonoids and other phenolics, nitrogen-containing low molecules (such as alkaloids and glucosinolates), lipids and amino acids.