With developing floral buds and leaves as materials,we studied ZjMADS1-box cloning and its expression profiles by construction of a suppression subtractive hybridization (SSH) library,RACE technology,and semi-quantitative RT-PCR.The results are as follows:(1)A 476 bp EST was identified as PISTILLATA (PI) gene related to floral development that was denominated as ZjMADS1-box.Based on the 476 bp sequence information,the full-length cDNA of ZjMADS1-box was successfully obtained by RACE from floral buds of the cultivar ‘Jinsi No.4’.(2)The ZjMADS1-box displays structural characters of PI homologs.The full-length cDNA of ZjMADS1-box is 957 bp,encoding 220 amino acids.On the amino acid sequence level,this gene shows the highest similarity (72.6%) with EgM2 gene of Eucalyptus grandis and MqPI gene of Melaleuca quinquenervia,and the lowest (61.8%) with CaPI gene of Capsicum annuum.ZjMADS1-box clusters with EgM2 and MqPI in phylogenetic tree.The predicted isoelectric point (pI) and molecular weight (Mw) of ZjMADS1-box is 9.75 and 25 587.5 Da,respectively.ZjMADS1-box is predicted to be a kind of hydrophilic and non-secreted proteins.(3)ZjMADS1-box is specifically expressed in floral organs.It is not expressed in vegetative tissues (organs) including tender stems,mature leaves,and axillary buds.In floral buds,expression level of ZjMADS1-box on April 30 and May 8 is higher than that on May 4,May 12,and May 16.The expression level,however,has no remarkable difference between different developing stages.This study will provide a scientific basis for fully clarifying the mechanism of floral development of Z.jujuba.