Project description: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
Project description: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 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.
Project description:When pollen lands on a receptive stigma, it germinates and extends a tube inside the transmitting tissue of the pistil to deliver the sperm cells for double fertilization. The growth of the pollen tube triggers significant alterations in its gene expression. The extent to which these changes occur in the vegetative cell or extend to the sperm cells transported by the tube is unclear, but important to determine since sperm cells are believed to acquire a competency for fertilization during pollen-pistil interactions. To address these questions, we compared the transcriptomes of Arabidopsis thaliana sperm cells and vegetative nuclei isolated from mature pollen grains with those isolated from in vitro grown pollen tubes. Importantly, we also compared with transcriptomes of sperm cells obtained from pollen tubes grown under semi in vivo conditions where tubes passed through a pistil section. Our data shows that extensive transcriptomic changes occur in sperm cells during pollen tube growth, some of which are elicited only as sperms are carried through the pistil. Their analysis reveals a host of previously unidentified transcripts that may facilitate sperm maturation and gamete fusion. The vegetative cell undergoes even more extensive transcriptomic reprogramming during pollen tube growth, mainly through the upregulation of genes associated with pollen tube growth and vesicle-mediated transport. Interestingly, ATAC-seq data shows that the promoters of genes up-regulated in sperm during pollen tube growth are already accessible in sperm chromatin of mature pollen grains, suggesting pre-configured promoter accessibility. This study's expression data can be further explored here: https://bar.utoronto.ca/eFP-Seq_Browser/.
Project description: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.
Project description:Transcription profiling of post-anthesis unfertilized pistil development and senescence in Arabidopsis, in a serie including samples from seven different stages according to pistil age in days post-anthesis (dpa). The time course started at anthesis and ended at 12-14 dpa, several days later of the loss of fruit set capacity. Keywords: Developmental time course
Project description:Mitochondria were purified from mature pollen and whole buds from Arabidopsis thaliana. Whole mitochondrial proteomes were obtained by shot-gun proteomics.