Genetic, molecular and parent-of-origin regulation of early embryogenesis in flowering plants.

Embryogenesis in flowering plants has fascinated biologists since at least the 19th century. Embryos of almost all flowering plants share common characteristics, including an asymmetric first division of the zygote, and multiple rounds of cell divisions that generate the major tissue types of the adult plant, usually within a few days of fertilization. This review focuses on early embryogenesis, including fertilization, the contributions of maternal and paternal genomes to the zygote and early embryo, cell fate decisions that create the apical and basal lineages, establishment of the shoot and root meristems, and formation of the other major tissue types in the adult plant. Because most genetic and molecular research on embryogenesis in plants has been conducted on the model species Arabidopsis thaliana, we highlight work on this species as well as research with Zea mays (maize) and Oryza sativa (rice).