Protein phosphorylation, one of the major post-translational modifications, plays a crucial role in cell signaling, DNA replication, gene expression and differentiation; and alters enzyme activity and other biological activities; and regulates cell proliferation and enlargement, phytohormone biosynthesis and signaling, plant disease resistance, and grain filling and quality during rice seed development. Research work on protein phosphorylation started in the 1950s with the discovery of phosphorylase a and phosphorylase b which are phospho and dephospho forms of the same enzyme. Over the last decade, rice proteomics has accomplished tremendous progress in setting up techniques to proteome nearly all tissues, organs and organelles. The progress made in this field is evident in number of research works. However, research on rice protein phosphorylation is still at its infancy and there are still many unanswered questions. In this review, the general description of protein phosphorylation, including history, structure, frequency of occurrence and function, are discussed. This work also elucidates the different methods for identification, qualification and finally, the progress in rice phosphoproteome research and perspectives.
