Abstract
Flowering plants have evolved a unique and complex fertilization system known as double fertilization. This event that two sperm cells fuse an egg cell and a central cell respectively, was discovered more than a century ago. However, the mechanism of fertilization remains largely unclear because these gamete fusions take place in the embryo sac, which is deeply embedded in the ovule. In this study, to address the mechanism of fertilization, we carried out a comprehensive analysis of gene expression profiles of the egg cells, sperm cells, and zygotes that were isolated from unpollinated or pollinated ovaries of rice. Additionally, to reveal whether two sperm cells have distinct identities for fusion with egg cell and central cell or not, investigations for monitoring gene expression profiles of each two sperm cells derived from one pollen are underway. Based on the results from these transcriptome analyses, we will discuss the possible molecular mechanisms in gamete fusion underlying reproductive event.
