Abstract: To study the function of Schizosaccharomyces pombe heavy metal tolerance factor 1 (SpHMT1) gene in Cd tolerance in Arabidopsis thaliana, the SpHMT1 gene encoding the PCs-Cd transporter in Arabidopsis was overexpressed. It was found that SpHMT1 enhanced the tolerance and accumulation of Cd, Cu, As and Zn, and failed to confer Cd2+ tolerance and accumulation when GSH and PC synthesis was blocked by L-buthioninesulfoximine (BSO). SpHMT1 was localized in tonoplast in Arabidopsis, and the energy-dispersive X-ray analysis showed that S was more present in vacuoles in transgenic plants, suggesting that the function of SpHMT1 in Arabidopsis depended on phytochelatins. On the other hand, constitutive expression of SpHMT1 delayed root to shoot transport of the metals, suggesting that roots can serve as a sink, with further reduction of metal content in shoots.

Key words: SpHMT1, Arabidopsis, cadmium tolerance, vacuole, phytochelatins