Abstract: In this work，a full-length cDNA sequence of chalcone synthase（CHS）gene was obtained from petals of Paeonia suffruticosa‘Caihui’using RT-PCR and RACE，named Ps-CHS1（GenBank accession No. GQ483511）. Sequence analysis indicated that Ps-CHS1 is 1 475 bp in full length and contains a 5′-untranslated region（5′-UTR）of 82 bp，a 3′-UTR of 208 bp，and an opening reading frame（ORF）of 1 185 bp encoding a 394 predicted amino acids residues which possessed all the conserved active sites for the CHS function as well as the family signature. Sequence alignment and phylogenetic analysis revealed that Ps-CHS1 shared more than 90% homology with CHS from plants in Salicaceae，Malvaceae and Rosaceae. Relative real-time PCR analysis indicated that Ps-CHS1 showed the highest transcript abundance in petals，moderate levels in sepals，low levels in leaves and stamens and the lowest levels in carpels.

Key words: tree peony, Paeonia suffruticosa, chalcone synthase gene, relative real-time PCR, tissue-specific expression