Project description:Survey of post pollination events in a sexually deceptive orchid (Ophrys fusca): a transcriptional approach Pollination through deception is a widespread phenomenon in angiosperm, and is extremely common in Orchidaceae family. One of the most striking pollination mechanism in orchids is known as sexual deception, in which flowers lure pollinators by foraging chemical (sex pheromones), visual (e.g. labellum colour and/or shape) and tactile (e.g. labellum pilosity) cues of the female insect pollinator. Ophrys has been used as a model genus to study sexual deception mechanism, mainly regarding chemical analysis in plant-insect association. Study was focused on Ophrys fusca, a species widely distributed in Mediterranean Basin. The main objective rely on Ophrys fusca gene expression study after pollination, through a transcriptional approach using cDNA microarrays. In order to evaluate pollination enhanced events, two different time points were selected: 2 days and 4 days after pollination. Ophrys fusca plants were sampled from a Portuguese natural occurring population. Plants were covered with a white and inert net, built specially for preventing pollinator’s visits in both pollinated and unpollinated flowers. Cross- pollination was performed manually with a sterile plastic stick. Five biological replicates (5 plants in each replicate) from each condition (pollinated and unpollinated) were collected in each time-point Flowers that demonstrate strict pollination regulation, as orchids, provide an excellent model system to unravel pollination- elicited mechanisms (i.e. petal senescence, pigmentation changes, ovary growth). Therefore, this study aims to contribute to the overall knowledge on orchid pollination biology, which is still lacking.
Project description:Survey of post pollination events in a sexually deceptive orchid (Ophrys fusca): a transcriptional approach Pollination through deception is a widespread phenomenon in angiosperm, and is extremely common in Orchidaceae family. One of the most striking pollination mechanism in orchids is known as sexual deception, in which flowers lure pollinators by foraging chemical (sex pheromones), visual (e.g. labellum colour and/or shape) and tactile (e.g. labellum pilosity) cues of the female insect pollinator. Ophrys has been used as a model genus to study sexual deception mechanism, mainly regarding chemical analysis in plant-insect association. Study was focused on Ophrys fusca, a species widely distributed in Mediterranean Basin. The main objective rely on Ophrys fusca gene expression study after pollination, through a transcriptional approach using cDNA microarrays. In order to evaluate pollination enhanced events, two different time points were selected: 2 days and 4 days after pollination. Ophrys fusca plants were sampled from a Portuguese natural occurring population. Plants were covered with a white and inert net, built specially for preventing pollinator’s visits in both pollinated and unpollinated flowers. Cross- pollination was performed manually with a sterile plastic stick. Five biological replicates (5 plants in each replicate) from each condition (pollinated and unpollinated) were collected in each time-point Flowers that demonstrate strict pollination regulation, as orchids, provide an excellent model system to unravel pollination- elicited mechanisms (i.e. petal senescence, pigmentation changes, ovary growth). Therefore, this study aims to contribute to the overall knowledge on orchid pollination biology, which is still lacking. 2 time points: 2 days and 4 days after pollination.Two-samples accessed: control (nonpollinated labella) and test (pollinated labella). 5 Biological replicates and 2 technical replicates (repeats of labelling and hybridization using randomly chosen biological replicates) in each time point were made.
Project description:The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographic scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a cDNA microarray containing 1,310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. We also identified differentially expressed genes during a time course experiment with four time points across nine days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca2+ homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first large-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca2+ homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis. Keywords: thermal stress response; coral bleaching 5 control and 5 heat-stressed RNA samples were hybridized in a 5-replicate dye-swap design (10 total hyb's).
Project description:The declining health of coral reefs worldwide is likely to intensify in response to continued anthropogenic disturbance from coastal development, pollution, and climate change. In response to these stresses, reef-building corals may exhibit bleaching, which marks the breakdown in symbiosis between coral and zooxanthellae. Mass coral bleaching due to elevated water temperature can devastate coral reefs on a large geographic scale. In order to understand the molecular and cellular basis of bleaching in corals, we have measured gene expression changes associated with thermal stress and bleaching using a cDNA microarray containing 1,310 genes of the Caribbean coral Montastraea faveolata. In a first experiment, we identified differentially expressed genes by comparing experimentally bleached M. faveolata fragments to control non-heat-stressed fragments. We also identified differentially expressed genes during a time course experiment with four time points across nine days. Results suggest that thermal stress and bleaching in M. faveolata affect the following processes: oxidative stress, Ca2+ homeostasis, cytoskeletal organization, cell death, calcification, metabolism, protein synthesis, heat shock protein activity, and transposon activity. These results represent the first large-scale transcriptomic study focused on revealing the cellular foundation of thermal stress-induced coral bleaching. We postulate that oxidative stress in thermal-stressed corals causes a disruption of Ca2+ homeostasis, which in turn leads to cytoskeletal and cell adhesion changes, decreased calcification, and the initiation of cell death via apoptosis and necrosis. Keywords: thermal stress response, time course, coral bleaching Time course with 4 time points and 4 biological replicates per time point. Each biological replicate at each time point was hybridized to a pooled reference control sample containing RNA from all control non-heat-stressed coral fragments.