Abstract: 【Objective】 The changes of proteome patterns during the middle stage of longan (Dimocarpus longan Lour.) somatic embryogenesis were analyzed to provide valuable evidence for further elucidating the mechanism of somatic embryogenesis.【Method】Synchronization of longan somatic embryogenesis during the middle stage was carried out, and changes of proteomic patterns during this period were analyzed by 2-DE and MS.【Result】During this period, diversity of expressed proteins declined with the development of somatic embryos of longan, but it showed a increase at torpedo stage. Newly expressed proteins at torpedo stage included those with a MW less than 66.0 kD and a pI of these proteins range between 5.00 and 7.00. Thirty-five differentially expressed proteins were identified, and many of them were related to somatic embryogenesis.【Conclusion】With the development of somatic embryo, somatic cells differentiated progressively and the amount of expressed proteins decreased. Proteins associated with oxidative stress, RAN2 and GTPase ObgE might be related to regulation of somatic embryogenesis in longan.

Key words: longan, somatic embryogenesis, proteomics