Abstract: Cymbidium ensifolium（L.）flower is highly evolved with a column（a fusion of the male and female reproductive organs）. Its complex floral architecture presents an exciting opportunity to examine column development. In flowering plants，class B，C and E floral homeotic genes play key roles in the specification of stamen and carpel identity. In this study，Fourteen class B，C and E unigenes （including DEF-，GLO-，AG-，SEP-，and AGL6-like unigenes）were detected from transcriptome data of C. ensifolium flower buds. Real-time quantitative PCR results showed that CeDEF1 and CeAGL6-1 were only strongly detected in the sepals and petals，and were significantly down-regulated in the lips. CeDEF3，CeDEF4 and CeAGL6-3 were expressed highly in the lips and columns，but were detected minimally in the sepals and lateral petals. CeAG1 and CeAG2 were strongly expressed in columns. In addition，the expression levels of CeDEF3，CeDEF4，CeAG1，CeAG2 and CeAGL6-3 were higher in column-like petals of‘Xinpinmei’than in petals of‘Tiegusu’. These results displayed that CeDEF3，CeDEF4，CeAG1，CeAG2 and CeAGL6-3 may play key roles in regulating the column formation of C. ensifolium.

Key words: Cymbidium ensifolium, MADS-box gene, column, development, real-time quantitative PCR