Proteomic analysis of embryo development in rice (Oryza sativa)

Although embryo development is a major subject in plant growth and development research, a number of aspects of the mechanism of this development process remain unknown. Rice (Oryza sativa) is an excellent monocot plant model for studying embryogenesis with a known genome sequence. Here, we conducted proteomic analysis of embryo development in rice (O. sativa L. ssp. indica cv. 9311). The aim was to investigate and characterize the changes in the protein expression profile during embryo development. For this purpose, the proteome of developing embryos was characterized by two-dimensional gel electrophoresis and nano liquid chromatography/mass spectrometry/mass spectrometry. Proteomic analyses identified 275 differentially expressed proteins throughout the 5 sequential developmental stages from 5 to 30 days after pollination. Most of these proteins were classified into eight functional categories: metabolism, protein synthesis/destination, disease and defense, transporter, transcription, signal transduction, cell growth/division, and storage proteins, which were involved in different cellular and metabolic processes. Hierarchical clustering analyses of protein expression profiles showed that highly expressed proteins in early stages were involved in metabolism, protein synthesis/destination, and most of the other cellular functions, whereas the proteins highly expressed in later stages functioned in the desiccation and dormancy of the embryo.