Comparative gene expression in synergid cells and antipodal cells at anthesis

Synergid cells represent the receptor cell type of angiosperm gametophytes that attract and receive the male pollen tube and are implicated in the transfer of the sperm cells to the target egg and central cells prior to double fertilization. The antipodals represent an accessory cell type that typically degenerates after fertilization; in rice it may initially have a short-lived nutritional role prior to endosperm establishment. We examined the transcriptome of these two cell types using Oryza sativa ssp. japonica (cv Katy) using the Affymetrix 57K rice genome GeneChip to provide an overview of genes activated at receptivity in the synergid and antipodal cells and transcript up- and down-regulated at female gametophyte maturity just prior to fertilization. This is part of a larger microarray paroject to examine the global program of gene expression during sexual reproduction in Oryza sativa which serves as a model angiosperm in which male and female gametophytic and embryonic cells may be readily isolated and characterized. Two female gametophytic accessory cell types were isolated from living embryo sacs, consisting of isolated synergid cells and antipodal cells collected at floral anthesis.