The responses of Arabidopsis thaliana to cadmium exposure explored via metabolite profiling

The metabolic responses of Arabidopsis thaliana to cadmium exposure was characterized in this study. A. thaliana was cultivated in medium contaminated with different cadmium concentrations (0, 5 and 50microM, respectively) for 2weeks. Metabolite analyses were performed using gas chromatography-mass spectrometry. More than 80 metabolites characterized by retention time indices and specific mass fragments were identified. The levels of carbohydrates, organic acids, amino acids, and other stress-responsive metabolites changed under cadmium stress. Treated plants showed increased levels of Ala, beta-ala, Pro, Ser, putrescine, Suc and other metabolites with compatible solute-like properties, notably 4-aminobutyric acid, glycerol, raffinose and trehalose, compared to control (untreated) plants. Studies indicated that concentrations of antioxidants (alfa-tocopherol, campesterol, beta-sitosterol and isoflavone) also increased significantly. These results confirm the important role of antioxidant defences in the mechanisms of plant-resistance to cadmium stress. Our results suggested that metabolic profiling is a powerful tool that can rapidly classify environmentally modified plants and simplify the process of cadmium-stress responses. These data will be helpful for better understanding of mechanisms of plant adaptation to cadmium stress at the metabolite level.