Cloning and expression analysis of CpPCS from Carex putuoshan

The hyperaccumulator Carex putuoshan was used as cloning material for the phytochelatin synthase (PCS) gene, and to characterize its expression following heavy metal stress. The results showed that the cDNA of CpPCS was 1 461 bp in length, and it encoded 486 amino acids with a molecular weight of 53.86 kDa and pI value of 6.12. As compared to other plants, the amino acid sequence similarity was approximately 63%. Phylogenetic analysis of PCS proteins from different species showed those of C. putuoshan were most closely related to those of Oryza sativa and Triticum aestivum. Real-time quantitative PCR analysis indicated that CpPCS and CePCS (Carex oshimensis 'Evergold') genes were expressed in the leaves. The CpPCS and CePCS genes were up-regulated in Pb and Zn treatments. Additionally, we investigated CpPCS structure, phylogenetic relationships, and gene expression patterns. Our results indicated that CpPCS might play an important role in heavy metal stress, and could be further utilized in plants.