Abstract: A full-length cDNA sequence of the homologous LEAFY gene from sugar apple（Annona squamosa L.），which was named as AsLEAFY（GenBank accession KP866145），was cloned by employing homology gene cloning and RACE approaches. Sequence analysis showed that the AsLEAFY gene contains a 1 236 bp open reading frame（ORF）encoding 411 amino acids. As the typical structure features of LEAFY（FLO）family，a 5′-N praline-rich region and a central acidic region were identified in the amino acid sequence of AsLEAFY protein. The deduced AsLEAFY protein is highly homologous to the LEAFY proteins from other various woody plants. Phylogenetic tree analysis indicated that AsLEAFY shows closer relationship with the LEAFYs in woody plants than in herbs. The real-time PCR results suggested that the AsLEAFY gene could be detected during the whole period of flower development. Interestingly，AsLEAFY gene showed a high transcription level in flower bud at the beginning stage and axillary bud of fruiting branches after defoliation. It is conjectured that AsLEAFY may play a crucial role in the early stage of flower organs formation in sugar apple.

Key words: sugar apple, Annona squamosa, LEAFY, flower development, expression pattern