Abstract: CeAGL6，a gene belongs to AGL6 class of the MADS-box gene family，was isolated from a normalized full-length cDNA library of Cymbidium ensifolium based on pooling strategy combined with PCR-based screening method. After bioinformatics analysis of CeAGL6，expression patterns，interacting protein and tobacco genetic transformation were performed to identify its functions in the flower development of Cymbidium ensifolium. Sequence analysis revealed the highly conserved MADS domain，K domain, and a typical motif of AGL6 class of MADS-box gene family in CeAGL6. The highest expression level of CeAGL6 was found in sepal，followed by pedicels，low level in petal，lip，and column，and expression in leaf and root was not detected. Overexpression of CeAGL6 caused an advanced flowering and novel phenotypes of four-petal flower，six-petal flower，petaloid stamens and a variety of irregular five-petal flower in transgenic tobacco. Yeast two-hybrid analysis indicated there were interactions between CeAGL6 and CeAP1，CePI1，CeAG1 or CeSEP3，but the homodimers cannot form by itself. The results showed that CeAGL6 was involved in promoting flowering and flower organ development of Cymbidium ensifolium.

Key words: Cymbidium ensifolium, flower development, AGL6 homologous gene, gene function