The ubiquitin-conjugating enzyme E2 gene,designated as BcUBCE2,was isolated from Brassica chinensis L.by cDNA-AFLP and RACE technologies.The full length sequence of BcUBCE2 gene was 830 bp,contained an open reading frame(ORF) of 456 bp that encoded 152 amino acid residues.Structural analysis revealed that the sequence contains an E2 ubiquitin-conjugating enzyme active site and a highly conserved cysteine.Phylogenetic analysis showed that BcUBCE2 protein has the closest relative with E2 protein from Arabidopsis thaliana.qRT-PCR results showed that the existence of BcUBCE2 was detectable in root,stem and leaf.The expression level of BcUBCE2 gene reached the highest under copper stress for 10 d.This showed that the BcUBCE2 gene may play an important role in the response to copper stress.