Toxicological effects of environmentally relevant lead and zinc in halophyte Suaeda salsa by NMR-based metabolomics.

Lead (Pb) and zinc (Zn) are two typical metal contaminants with high levels in both seawater and sediment in the intertidal zones of the Bohai Sea. Suaeda salsa is the pioneer halophyte plant in the intertidal zones of the Bohai Sea. In the present work, the short (1 week) and long term (1 month) toxicological effects of environmentally relevant concentrations of Pb and Zn were characterized in S. salsa using NMR-based metabolomics combined with antioxidant enzyme activities. After metal exposure for 1 week, no significant metabolic responses were detected in root tissues of S. salsa. The significant metabolic responses included the increase of isocaproate, glucose and fructose, and decrease of malate, citrate and sucrose in root tissues of S. salsa exposed to Pb for 1 month. The increased phosphocholine and betaine, and decreased choline were uniquely found in Zn-exposed samples. The metabolic changes including decreased malate, citrate and sucrose were detected in both Pb and Zn-exposed groups. These metabolic biomarkers revealed that both Pb and Zn exposures could induce osmotic stress and disturbances in energy metabolism in S. salsa after exposures for 1 month. Overall, this work demonstrates that metabolomics can be used to elucidate toxicological effects of environmentally relevant metal contaminants using halophyte S. salsa as the bioindicator.