Project description:Transcriptional analysis of stigmas was performed to identify molecules functioning in compatible pollination. Stigmas of A. thaliana Col-0 were collected (i) at 0 min or 15 min after pollination and (ii) before or at 15 min after pollen coat adhesion, and used for microarray analysis. Genes up-regulated after pollination and after pollen coat adhesion were identified. .
Project description:Transcriptional analysis of stigmas was performed to identify molecules functioning in compatible pollination. Stigmas of A. thaliana Col-0 were collected (i) at 0 min or 15 min after pollination and (ii) before or at 15 min after pollen coat adhesion, and used for microarray analysis. Genes up-regulated after pollination and after pollen coat adhesion were identified. . Four-condition experiment, stigmas at 0 min vs. 15 min after pollination; stigmas before vs. at 15 min after pollen coat adhesion.
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:Convergent evolution, the independent evolution of similar traits in different species under similar environmental pressures, is widespread across many taxa. In plants, a key example is the repeated evolution of floral traits associated with the transition from outcrossing to self- fertilization, often resulting in the “selfing syndrome” (e.g., reduced flower size, loss of scent, and altered reproductive strategies). However, potentially overlooked changes concern the pollen coat, which plays a role in different aspects of outcrossing strategy. To investigate this, we compared pollen morphology and proteomes between selfing and outcrossing species in the 2 Arabidopsis and Capsella genera, representing three independent selfing transitions. Pollen coat area diminished with the age of the selfing transition, with significant reductions in A. thaliana and Capsella rubella, but not in A. lyrata (recent transition, no selfing syndrome). Moreover, differentially expressed pollen coat proteins, primarily related to pathogen response, were shared across selfer-outcrosser contrasts more than expected by chance. However, similar functions appeared in random outcrosser-outcrosser comparisons, suggesting additional drivers beyond mating system transitions. Overall, our findings reveal convergent evolution of pollen coat morphology and protein composition following selfing transitions, while highlighting pathogen response as a key factor driving the fast evolution of pollen coat protein independently of the mating system.
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:The expression analysis had two goals: (1) look at relative transcription within mature pollen grains (2) compare expression in the stigma during pollination with either compatible or in-compatible pollen. Two pairwise comparisons, (i) unpollinated stigma vs. stigma pollinated with compatible pollen, and (ii) unpollinated stigma vs stigma pollinated with incompatible pollen. The genotype where stigma samples were harvested from is F1-30, and this is also the pollen source during an incompatible pollination reaction. The compatible pollen source is the variety Foxtrot (heterogeneous populations).
Project description:Sexual reproduction in flowering plants involves intimate interactions between the growing pollen tube and the female reproductive structure. These interactions start immediately after pollen landing on the stigma and continue during the pollen tube journey through the style and the ovary. Thus, well before fertilization, genes in the gynoecium are affected by the growing pollen tubes. Genes activated at a distance in the ovary before pollen tubes arrival represent one class of such genes. Using a global transcriptomic approach, expression profiles obtained from compatible (SC), incompatible (SI), semi-compatible (SeC) and interspecific (IS) pollinations revealed that these pollinations are perceived differently from a distance in the ovary. As the pollen tubes grew along the style, more and more genes became specific for each pollination type, although even early on when no difference could be observed in pollen tube growth rates, each pollination type already displayed its specific signature. Wounding experiments as well as methyl jasmonate treatment were also conducted to determine if transmitting tissue cell death caused by pollen tube growth in the style could also activate gene expression at distance in the ovary. Our data suggest that pollen tube growth in the style is at least partially perceived as a wounding aggression, and that a SI pollination is more akin to a wound response than the other pollination type tested, suggesting similarities in the signaling pathways controlling pollen recognition and stress responses. More importantly, our transcriptomic analysis reveals a highly specific recognition of various pollination types that is relayed from a distance to the ovary ahead of fertilization.