Objective  Still unclear regulatory functions of DlAGOMEL1 on the nonembryonic callus and different embryogenic cultures of longan (Dimocarpus longan) were investigated.

  Method  From the longan genome database, the full-length cDNA sequences (CDS) of DlAGOMEL1 and its promoter were obtained using RT-PCR. Bioinformatics of this gene was analyzed and the relative expressions of this gene in embryogenic cultures were detected by real-time quantitative PCR. The recombinant plasmid was constructed from the transient fusion expression vector, and the onion inner epidermal cells transformed into transient onion cells. Green fluorescence signal of the cells was searched under a fluorescence confocal microscope.

  Result  The CDS of DlAGOMEL1 was 2,655 bp which encoded 884 amino acids and the promoter was 1,512 bp. The DlAGOMEL1 of longan and other plants were highly conserved as shown in a multiple sequences analysis. Phylogenetic tree of the protein indicated its close relation with Populars euphonium but not with monocotyledonous plants, such as rice and maize. The gene expressed differently in somatic embryo development stages—most strongly at cotyledon embryo stage and least at spherical embryo stage. The subcellular localization of DlAGOMEL1 was found in cytoplasm.

  Conclusion  Since the relative expression of DlAGOMEL1 was shown to be high at the late stage of longan somatic embryo, the gene might be functionally active in the late stage of the development. The revealed subcellular localization of the gene seemed to predispose its involvement in the cytoplasm of longan.