Transcription profiling by array of Arabidopsis pollen and pollen tubes grown in vitro and in vivo

Pollen tubes extend through pistil tissues and are guided to ovules where they release sperm for fertilization. Although pollen tubes can germinate and elongate in a synthetic medium, their trajectory is random and their growth rates are slower compared to growth in pistil tissues. Furthermore, interaction with the pistil renders pollen tubes competent to respond to guidance cues secreted by specialized cells within the ovule. The molecular basis for this potentiation of the pollen tube by the pistil remains uncharacterized. We used a surgical procedure to obtain large quantities of uncontaminated pollen tubes that grew through the pistil and defined their transcriptome by microarray analysis. We also characterized the transcriptome of in vitro-grown pollen tubes (for 0.5hours or 4hours) and dessicated mature pollen in Arabidopsis. Experiment Overall Design: Pollen and pollen tubes were collected as described in the protocols section for RNA extraction and hybridization on Affymetrix ATH1 Genechip microarrays.