Abstract：To investigate the mechanism of B function genes for double flower development in Camellia japonica, CjDEF-1 was cloned and its expression characteristic was analyzed. CjDEF-1 fragment was cloned from C. japonica Hongshibaxueshi flower buds based on homologous sequence from online blast results, and the full length of CjDEF-1 cDNA was amplified by RACE method(GenBank Accession No.HM773024.1). The spatialtemporal expression pattern of CjDEF-1 gene was studied by Real-time PCR. The results exhibited that CjDEF-1 cDNA sequence length was 1 013 bp and included an completed ORF(open reading frame) and encoded 226 amino acids. The sequence analysis showed that there were four encoding amino acid differences between C. japonica subsp. rusticana and C. japonica Hongshibaxueshi. The highest expression was in small buds, the lowest was in middle buds, while the expression went up at flower stage. The expression results from highest to lowest at different flower tissue were central petals, outside petals, middle petals, sepals and bracts. These differences with single flower showed that CjDEF-1 gene may be involved in formal double thigmomorphogenesis in Camellia.
