Plant reproduction depends on the concerted activation of many genes to assure the correct communication between pollen and pistil. Here we queried the whole transcriptome of Arabidopsis thaliana in order to identify genes with specific reproductive functions. We used the ATH1 whole genome array to profile wild-type unpollinated pistils and unfertilized ovules in comparison with the expression profile of pistils 0.5, 3.5 and 8.0 hours after pollination KEYWORDS: time course Overall design: Flowers at the developmental stage 12c were emasculated 24 hours before pollination. Pistils were collected at 0, 0.5, 3.5 and 8 Hours After Pollination (HAP) and immediately frozen in liquid nitrogen. Unfertilized ovules were collected by the funiculus from dissected UP and immediately frozen in liquid nitrogen. To minimize biological variation 20 pistils were collected from a minimum of 10 plants and for ovule isolation 50 pistils were used from about 30 plants to isolate approximately 1500 ovules for each replicate experiment.