Cloning and Expression Analysis of PsCCH from Populus simonii under Stresses of Heavy Metal

The CCH gene from Populus simonii leaf was cloned according to a strategy combining bioinformatics and molecular biological approaches and its expression in response to heavy metals and plant growth regulators was detected by q PCR. This gene encodes a polypeptide of 85 amino acids,named as Ps CCH. The deduced amino acid sequence of Ps CCH possesses the conserved metal-binding motif in its N-terminal( MXCXXC) and has the classicβαββαβ-fold structure. Phylogeny analysis showed that the Ps CCH was much closer to the CCH from Hevea brasiliensis,Jatropha curcas and Vitis vinifera( with 90%- 93% in amino acids similarity). The results of q PCR showed that the expression of Ps CCH was regulated by various heavy metals and plant growth regulators: the Ps CCH transcripts increased within one hour and then decreased to a lower level after 3 hours,such as in zinc,aluminum,low copper and jasmonic acid treatments; and the Ps CCH transcripts continuously decreased during the treatment,such as in high copper,cobalt,mercury and salicylic acid treatments.