Proteomic analysis reveals different involvement of proteins during the maintenance and release of rice seed dormancy

The short storage life of harvested rice seed is an important constraint that threatens global food security. Seed dormancy is one of the major characteristics which controls seed storage life. Elucidating it will help breeding of high-quality rice varieties. However, its mechanisms remain unclear. Taking advantage of a deep dormant rice variety FH7185, which shown only 15% germination rate of freshly harvested seeds, we analyzed its dormancy and the sensitivity to hormone treatment, then established a comprehensive proteome map of the rice seed using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and isobaric tags for relative and absolute quantification (iTRAQ) of proteins in dormant and after-ripening seeds. In total, 3719 different proteins were identified and established a comprehensive proteome map of the rice seed to find quantitatively regulated proteins that played roles in seed dormancy. And, obvious accumulation was observed for a wide variety of proteins in metabolic pathways and plant hormone signal transduction. The analysis of abscisic acid (ABA) and gibberellin (GA) indicated that the deep dormancy of FH7185 was not directly affected by the content of ABA and GA. Thus, the maintenance and release of seed dormancy are not only regulated by the hormone, but also coordinated by other regulatory factors. Our results uncover the dynamic metabolic models underlying seed dormancy will lay the foundation for further study on the regulation mechanism of rice seed dormancy.