Expression of Dad1 in Maize Seed Development

Dad1 is a highly conserved programmed cell death (PCD) suppressor gene. Using digoxigenin-labeled anti-sense RNA probe, the expression of Dad1 cDNA in Arabidopsis was detected in developing maize seed tissues, including ovary, endosperm and embryo. Our results of in situ hybridization revealed that Dad1 was expressed in degenerating tissues, such as the ovary wall, the integument (Fig.1 BC), the mature endosperm (Fig.1 E) and the root cap (Fig.2 A), as well as in some vigorously metabolizing cells such as the meristematic cells of root tip (Fig.2 AB), the cotyledon cells (Fig.2 CD), the female germ cells (Fig.1 C) and the dividing endosperm cells (Fig.1 C) in a temporal and spatial manner. These results show that, as other Dad1 homologs, maize Dad1 may also play a role in maize embryo development and in PCD during endosperm degeneration.