We identified a small zinc finger protein, MBS, as a new mediator of singlet oxygen responses in Chlamydomonas and Arabidopsis. MBS is required for induction of singlet oxygen-dependent gene expression and, upon oxidative stress, accumulates in distinct granules in the cytosol of Arabidopsis cells. First, we recorded changes in light stress-regulated gene expression profiles after genetically perturbing MBS function by isolating mutants for the two MBS genes (MBS1 and MBS2) and by overexpression of MBS1 in Arabidopsis thaliana. Then, these light stress-related gene expression profiles were analyzed with respect to genes specifically responding to singlet oxygen and hydrogen peroxide/superoxide. The results indicated that MBS inactivation leads to an impaired response to singlet oxygen signaling under light stress.
A mediator of singlet oxygen responses in Chlamydomonas reinhardtii and Arabidopsis identified by a luciferase-based genetic screen in algal cells.
Specimen part, Treatment
View SamplesUnderstanding the response processes in cellular systems to external perturbations is a central goal of large-scale molecular profiling experiments. We investigated the molecular response of yeast to increased and lowered temperatures relative to optimal reference conditions across two levels of molecular organization: the transcriptome using a whole yeast genome microarray and the metabolome applying the GC/MS technology with in-vivo stable-isotope labeling for accurate relative quantification of a total of 50 different metabolites. The molecular adaptation of yeast to increased or lowered temperatures relative control conditions at both the metabolic and transcriptional level is dominated by temperature-inverted differential regulation patterns of transcriptional and metabolite responses and the temporal response observed to be biphasic. The set of previously described general environmental stress response (ESR) genes showed particularly strong temperature-inverted response patterns. Among the metabolites measured, trehalose was detected to respond strongest to the temperature stress and with temperature-inverted up and downregulation relative to control, mid-temperature conditions. Although associated with the same principal environmental parameter, the two different temperature regimes caused very distinct molecular response patterns at both the metabolite and the transcript level. While pairwise correlations between different transcripts and between different metabolites were found generally preserved under the various conditions, substantial differences were also observed indicative of changed underlying network architectures or modified regulatory relationships. Gene and associated gene functions were identified that are differentially regulated specifically under the gradual stress induction applied here compared to abrupt stress exposure investigated in previous studies, including genes of as of yet unidentified function and genes involved in protein synthesis and energy metabolism.
No associated publication
Time
View SamplesSulphur is an essential macronutrient for plant growth and development. Reaching a thorough understanding of the molecular basis for changes in plant metabolism depending on the sulphur-nutritional status at the systems level will advance our basic knowledge and help target future crop improvement. Although the transcriptional responses induced by sulphate starvation have been studied in the past, knowledge of the regulation of sulphur metabolism is still fragmentary. This work focuses on the discovery of candidates for regulatory genes such as transcription factors (TFs) using omics technologies. For this purpose a short term sulphate-starvation / re-supply approach was used. ATH1 microarray studies and metabolite determinations yielded 21 TFs which responded more than 2-fold at the transcriptional level to sulphate starvation. Categorization by response behaviors under sulphate-starvation / re-supply and other nutrient starvations such as nitrate and phosphate allowed determination of whether the TF genes are specific for or common between distinct mineral nutrient depletions. Extending this co-behavior analysis to the whole transcriptome data set enabled prediction of putative downstream genes. Additionally, combinations of transcriptome and metabolome data allowed identification of relationships between TFs and downstream responses, namely, expression changes in biosynthetic genes and subsequent metabolic responses. Effect chains on glucosinolate and polyamine biosynthesis are discussed in detail. The knowledge gained from this study provides a blueprint for an integrated analysis of transcriptomics and metabolomics and application for the identification of uncharacterized genes.
Transcriptome and metabolome analysis of plant sulfate starvation and resupply provides novel information on transcriptional regulation of metabolism associated with sulfur, nitrogen and phosphorus nutritional responses in Arabidopsis.
Specimen part
View SamplesSome soil bacteria promote plant growth, including Pseudomonas species.
No associated publication
Age, Specimen part, Treatment
View SamplesNine accessions of Arabidopsis were sampled before and after 14d of cold acclimation at 4°C. Transcript data were combined with metabolite data and related to quantitative measurement of plant freezing tolerance as determined by leaf electrolyte leakage assays.
Natural genetic variation of freezing tolerance in Arabidopsis.
Specimen part
View SamplesFloral organs are extremely sensitive to stress during anthesis and lead to severe yield loss. Rice anthers and pollinated pistils of two cultivars with contrasting tolerance to heat and drought stress under variable conditions, including control, heat, combined heat and drought stress, were used to explore gene expression pattern in male and female reproductive organs during anthesis under control and stress conditions. More gene regulation was induced by combined drought and heat stress than heat in anthers of both cultivars. N22 showed less regulation under combined stress than Moroberekan. The overlap of regulated genes between two cultivars was rather low, indicated the distinct molecular stress responses.
No associated publication
Specimen part
View SamplesPlant seeds prepare for germination already during seed maturation. We performed a detailed transcriptome analysis of barley grain maturation, desiccation and germination in two tissue fractions (endosperm/aleurone = e/a and embryo = em) using the Affymetrix barley1 chip.
Barley grain maturation and germination: metabolic pathway and regulatory network commonalities and differences highlighted by new MapMan/PageMan profiling tools.
No sample metadata fields
View Samples- Background and Aims: Oxygen can fall to low concentrations within plant tissues, either because of environmental factors that decrease the external oxygen concentration or because the movement of oxygen through the plant tissues cannot keep pace with the rate of oxygen consumption. Recent studies document that plants can decrease their oxygen consumption in response to relative small changes in oxygen concentrations to avoid internal anoxia. The molecular mechanisms underlying this response have not been identified yet. The aim of this study was to use transcript and metabolite profiling to investigate the genomic response of Arabidopsis roots to a mild decrease in oxygen concentrations.
Transcript and metabolite profiling of the adaptive response to mild decreases in oxygen concentration in the roots of arabidopsis plants.
No sample metadata fields
View SamplesTo investigate the response of Arabidopsis thaliana plants to non-freezing, cool temperatures, we subjected four week old plants to various chilling temperatures at defined times during the diurnal cycle to control for diurnal effects on transcription. From the same plants, metabolites and enzyme activities were measured as well. Interestingly a gradual change could be observed over a wide range of temperatures. Some of which could be attributed to the CBF program.
Multilevel genomic analysis of the response of transcripts, enzyme activities and metabolites in Arabidopsis rosettes to a progressive decrease of temperature in the non-freezing range.
Specimen part
View SamplesUsually starch is nearly depleted at the end of the night. To induce a gradual depletion of carbon, we have analysed the global response of transcripts during an extension of the night, where carbon becomes severely limiting from about four hours onwards.
Global transcript levels respond to small changes of the carbon status during progressive exhaustion of carbohydrates in Arabidopsis rosettes.
Specimen part
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