Project description:Upon exposure to light, plant cells quickly acquire photosynthetic competence by converting pale etioplasts into green chloroplasts. This developmental transition involves the de novo biogenesis of the thylakoid system, and requires reprogramming of metabolism and gene expression. Etioplast-to-chloroplast differentiation involves massive changes in plastid ultrastructure, but how these changes are connected to specific changes in physiology, metabolism and expression of the plastid and nuclear genomes is poorly understood. Here a new experimental system in the dicotyledonous model plant tobacco (Nicotiana tabacum) that allows us to study the leaf de-etiolation process at the systems level. We have determined the accumulation kinetics of photosynthetic complexes, pigments, lipids and soluble metabolites, and recorded the dynamic changes in plastid ultrastructure and in the nuclear and plastid transcriptomes. Our data describe the greening process at high temporal resolution, resolve distinct genetic and metabolic phases during de-etiolation, and reveal numerous candidate genes that may be involved in light-induced chloroplast development and thylakoid biogenesis.
2019-03-09 | GSE128049 | GEO
Project description:complete plastid genomes of Quercus
| PRJNA422358 | ENA
Project description:complete plastid genomes of Quercus
Project description:Chloroplast biogenesis represents a crucial step in seedling development, and is essential for the transition to autotrophic growth in plants. This light-controlled process relies on the transcription of nuclear and plastid genomes that drives the effective assembly and regulation of the photosynthetic machinery. Here we reveal a novel regulation level for this process by showing the involvement of chromatin remodelling in the coordination of nuclear and plastid gene expression for proper chloroplast biogenesis and function. The two Arabidopsis homologs of the yeast EPL1 proteins, core components of the NuA4 histone acetyl-transferase complex, are essential for the correct assembly and performance of chloroplasts. EPL1 proteins are necessary for the coordinated expression of nuclear genes encoding most of the components of chloroplast transcriptional machinery, specifically promoting H4K5Ac deposition in these loci. These data unveil a key participation of epigenetic regulatory mechanisms in the coordinated expression of the nuclear and plastid genomes.
Project description:Bigelowiella natans is a marine chlorarachniophyte whose plastid was acquired secondarily via endosymbiosis with a green alga. Integrating a photosynthetic endosymbiont within the host metabolism on route to plastid evolution would require the acquisition of strategies for coping with changes in light intensity and modifications of host genes to appropriately respond to changes in photosynthetic metabolism. To investigate the transcriptional response to light intensity in chlorarachniophytes, we conducted an RNA-seq experiment to identify differentially-expressed genes following four-hour shift to high or very-low light. A shift to high light altered the expression of over 2000 genes, many involved with photosynthesis, primary metabolism, and reactive-oxygen scavenging. These changes are related to an attempt to optimize photosynthesis and increase energy sinks for excess reductant, while minimizing photo-oxidative stress. A transfer to very-low light resulted in a lower photosynthetic performance and metabolic alteration, reflecting an energy-limited state. Genes located on the nucleomorph, the vestigial nucleus in the plastid, had few changes in expression in either light treatment, indicating this organelle has relinquished most transcriptional control to the nucleus. Overall, during plastid origin, both host and transferred endosymbiont genes evolved a harmonized transcriptional network to respond to a classic photosynthetic stress.