Cysteine- and glutathione-mediated uptake of lead and cadmium into Zea mays and Brassica napus roots

• Published in: Environmental pollution (1987) Vol. 157; no. 8; pp. 2558 - 2563
• Main Authors: Vadas, Timothy M., Ahner, Beth A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2009; Elsevier
• Subjects: Biodegradation, Environmental; Biological and medical sciences; Brassica napus; Brassica napus - metabolism; Cadmium; Cadmium - metabolism; canola; corn; cysteine; Cysteine - metabolism; Fundamental and applied biological sciences. Psychology; glutathione; Glutathione - metabolism; Lead; Lead - metabolism; Metal transport; Metals, Heavy - metabolism; Non agrochemicals pollutants; Phytopathology. Animal pests. Plant and forest protection; Phytoremediation; polluted soils; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; Soil - chemistry; Soil Pollutants - metabolism; soil pollution; Thiol; thiols; uptake mechanisms; Zea mays; Zea mays - metabolism; Lead; Cadmium; Thiol; Metal transport; Phytoremediation; Monocotyledones; Cysteine; Soil pollution; Transport process; Decontamination; Cruciferae; Gramineae; Dicotyledones; Angiospermae; Bioremediation; Glutathione; Vegetals; Zea mays; Transition metal; Uptake; Heavy metal; Trace element; Aminoacid; Brassica napus; Spermatophyta
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2009.02.036

This study examines a new mechanism for the uptake of Pb and Cd into Brassica napus and Zea mays roots. During hydroponic experiments, the uptake of Pb and Cd was enhanced in the presence of cysteine and glutathione, whereas no or very low uptake was observed in EDTA and penicillamine controls. Uptake rates were also enhanced after pre-exposure to cysteine or glutathione and inhibited in the presence of vanadate, suggesting a biological mechanism of uptake. Increasing concentrations of glutathione in solution resulted in decreasing Pb uptake rates, indicating competition for transport between free-glutathione and Pb–glutathione species. Pb uptake in the presence of increasing cysteine concentrations resulted in decreased uptake initially but linearly increasing uptake at higher concentrations. Experimentation showed concentration dependent Pb uptake rates. We speculate that there are specific transporters for these thiol ligands and describe what barriers remain for application of this novel transport mechanism in chelator-assisted phytoremediation. Cysteine and glutathione mediate the transport of lead and cadmium into plant roots.