Project description:Controlled hypobaria presents biology with an environment that is never encountered in terrestrial ecology, yet the apparent components of hypobaria are stresses typical of terrestrial ecosystems. High altitude, for example, presents terrestrial hypobaria always with hypoxia as a component stress, since the relative partial pressure of O2 is constant in the atmosphere. Laboratory-controlled hypobaria, however, allows the dissection of pressure effects away from the effects typically associated with altitude, in particular hypoxia, as the partial pressure of O2 can be varied. In this study, whole transcriptomes of plants grown in ambient (97 kPa/pO2 = 21 kPa) atmospheric conditions were compared to those of plants transferred to five different atmospheres of varying pressure and oxygen composition for 24 h: 50 kPa/pO2 = 10 kPa, 25 kPa/pO2 = 5 kPa, 50 kPa/pO2 = 21 kPa, 25 kPa/pO2 = 21 kPa, or 97 kPa/pO2 = 5 kPa. The plants exposed to these environments were 10 day old Arabidopsis seedlings grown vertically on hydrated nutrient plates. In addition, 5 day old plants were also exposed for 24 h to the 50 kPa and ambient environments to evaluate age-dependent responses. The gene expression profiles from roots and shoots showed that the hypobaric response contained more complex gene regulation than simple hypoxia, and that adding back oxygen to normoxic conditions did not completely alleviate gene expression changes in hypobaric responses.
Project description:Controlled hypobaria presents biology with an environment that is never encountered in terrestrial ecology, yet the apparent components of hypobaria are stresses typical of terrestrial ecosystems. High altitude, for example, presents terrestrial hypobaria always with hypoxia as a component stress, since the relative partial pressure of O2 is constant in the atmosphere. Laboratory-controlled hypobaria, however, allows the dissection of pressure effects away from the effects typically associated with altitude, in particular hypoxia, as the partial pressure of O2 can be varied. In this study, whole transcriptomes of plants grown in ambient (97 kPa/pO2 = 21 kPa) atmospheric conditions were compared to those of plants transferred to five different atmospheres of varying pressure and oxygen composition for 24 h: 50 kPa/pO2 = 10 kPa, 25 kPa/pO2 = 5 kPa, 50 kPa/pO2 = 21 kPa, 25 kPa/pO2 = 21 kPa, or 97 kPa/pO2 = 5 kPa. The plants exposed to these environments were 10 day old Arabidopsis seedlings grown vertically on hydrated nutrient plates. In addition, 5 day old plants were also exposed for 24 h to the 50 kPa and ambient environments to evaluate age-dependent responses. The gene expression profiles from roots and shoots showed that the hypobaric response contained more complex gene regulation than simple hypoxia, and that adding back oxygen to normoxic conditions did not completely alleviate gene expression changes in hypobaric responses.
Project description:Extreme hypobaria is a novel abiotic stress that is outside the evolutionary experience of terrestrial plants. In natural environments, the practical limit of atmospheric pressure experienced by higher plants is about 50 kPa or ~.5 atmospheres; a limit that is primarily imposed by the combined stresses inherent to high altitude conditions of terrestrial mountains. However, in highly controlled chambers and within extra-terrestrial greenhouses the atmospheric pressure component can be isolated from other high altitude stresses such as temperature, desiccation, and even hypoxia. In addition, hypobaria can be carried to extremes beyond what is possible in terrestrial biomes, and explored as a single variable in the examination of plant responses to novel stress. Previous studies have shown that plants adjust to hypobaric stress by differentially expressing suites of genes in unique combinations that are not equal to the dissected components of hypobaric stress (such as hypoxia and desiccation). Here we examine the organ-specific progression of transcriptional strategies for physiological adaptation to hypobaric stress over time. An abrupt transition from a near-sea level pressure of 97 kPa to only 5 kPa is accompanied by the differential expression of hundreds of genes. However, the transcriptomic reaction to hypobaric conditions lying between these two extremes reveals complex, organ-specific responses that vary over a time course of hypobaric exposure, and that are also not linear with respect to a simple gradient of severity. It is also clear that plants adjust over time such that the gene expression patterns that are initially elicited to cope with hypobaria are mediated as plants adjust their metabolism to this environment. The patterns of genome-wide changes in gene expression across a gradient of atmospheric pressures, and over a time course of several days allows for the development of theories of how plant metabolisms may be adapting to changes in atmospheric pressures.
Project description:Extreme hypobaria is a novel abiotic stress that is outside the evolutionary experience of terrestrial plants. In natural environments, the practical limit of atmospheric pressure experienced by higher plants is about 50 kPa or ~.5 atmospheres; a limit that is primarily imposed by the combined stresses inherent to high altitude conditions of terrestrial mountains. However, in highly controlled chambers and within extra-terrestrial greenhouses the atmospheric pressure component can be isolated from other high altitude stresses such as temperature, desiccation, and even hypoxia. In addition, hypobaria can be carried to extremes beyond what is possible in terrestrial biomes, and explored as a single variable in the examination of plant responses to novel stress. Previous studies have shown that plants adjust to hypobaric stress by differentially expressing suites of genes in unique combinations that are not equal to the dissected components of hypobaric stress (such as hypoxia and desiccation). Here we examine the organ-specific progression of transcriptional strategies for physiological adaptation to hypobaric stress over time. An abrupt transition from a near-sea level pressure of 97 kPa to only 5 kPa is accompanied by the differential expression of hundreds of genes. However, the transcriptomic reaction to hypobaric conditions lying between these two extremes reveals complex, organ-specific responses that vary over a time course of hypobaric exposure, and that are also not linear with respect to a simple gradient of severity. It is also clear that plants adjust over time such that the gene expression patterns that are initially elicited to cope with hypobaria are mediated as plants adjust their metabolism to this environment. The patterns of genome-wide changes in gene expression across a gradient of atmospheric pressures, and over a time course of several days allows for the development of theories of how plant metabolisms may be adapting to changes in atmospheric pressures.
Project description:The aim of this study was to analyze the impact of autotetraploidy on gene expression in Arabidopsis thaliana by comparing diploid versus tetraploid transcriptomes. In particular, this included the comparison of the transcriptome of different tetraploid A. thaliana ecotypes (Col-0 vs. Ler-0). The study was extended to address further aspects. One was the comparison of the transcriptomes in subsequent generations. This intended to obtain information on the genome wide stability of autotetraploid gene expression. Another line of work compared the transcriptomes of different diploid vs. tetraploid tissues. This aimed to investigate whether particular gene groups are specifically affected during the development of A. thaliana autotetraploids. Samples 1-8: Arabidopsis thaliana Col-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Col-0 seedlings. The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 lines. Samples 9-12: Arabidopsis thaliana Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Ler-0 seedlings. The experiment was carried out with pedigree of independently generated and assessed tetraploid Ler-0 lines. Samples 13-24: Arabidopsis thaliana Col-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Col-0 leaves (6th - 8th). The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 lines. Samples 25-32: Arabidopsis thaliana Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Ler-0 leaves (6th - 8th). The experiment was carried out with pedigree of independently generated and assessed tetraploid Ler-0 lines. Samples 33-36: Arabidopsis thaliana Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of tetraploid vs. tetraploid Ler-0 seedlings from the second (F2) and third (F3) generation after induction, respectively. The experiment was carried out with pedigree of independently generated and assessed tetraploid Ler-0 lines. Samples 37-40: Arabidopsis thaliana Col-0 tetraploid transcriptome. Transcriptional profiling and comparison of tetraploid vs. tetraploid Col-0 seedlings from the second (F2) and third (F3) generation after induction, respectively. The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 lines. Samples 41-44: Arabidopsis thaliana Col-0/Ler-0 diploid transcriptome. Transcriptional profiling and comparison of diploid Col-0 vs. diploid Ler-0 seedlings. The experiment was carried out with pedigree of esrablished lines. Samples 45-48: Arabidopsis thaliana Col-0/Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of tetraploid Col-0 vs tetraploid Ler-0 seedlings. The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 and Ler-0 lines.
Project description:Genes of the of Arabidopsis thaliana guard cells transcriptome that respond to high CO2 and darkness were identified and compared to the ABA- and low humidity treated samples of Experiment GSE41054 in Arabidopsis thaliana enriched guard cell samples.
Project description:Transcriptional profiling of cotyledon transcriptomics at the seedling stage (6 d) by comparison of wild-type vs. cotyledon-less laterne (= pid enp) homozygous mutant. The goal was to determine the transcriptomic profile of a cotyledon. The experiment took advantage of the endogenously caused lack of cotyledons instead of dissecting these organs, which would cause wound-induced expression.This was achieved by comparing seedlings of the Arabidopsis thaliana pid enp double mutant, which is incapable to generate cotyledons. This is caused by the loss of apical cell polarisation of the auxin efflux carrier PIN1 in epidermal cells during embryogenesis.