Growth daylength, ambient CO2 level, and intracellular hydrogen peroxide (H2O2) availability all impact plant function by modulating signalling pathways, but interactions between them remain unclear. Using a whole-genome transcriptomics approach, we exploited the conditional photorespiratory nature of the catalase-deficient cat2 mutant to identify gene expression patterns responding to these three factors. Arabidopsis Col-0 and cat2 grown for 5 weeks in high CO2 in short days (SD) were transferred to air in SD or long days (LD), and microarray analysis was performed. Of more than 500 genes differentially expressed in Col-0 between high CO2 and transfer to air in SD, the response of about one-third was attenuated by transfer to air in LD. H2O2-responsive genes in cat2 were highly dependent on daylength. The majority of H2O2-induced genes were more strongly up-regulated after transfer to air in SD than to LD, while a smaller number showed an opposing pattern. Responses of other H2O2-dependent genes indicate redox-modulation of the daylength control of fundamental cell processes. The overall analysis provides evidence that (1) CO2 level modulates stress-associated gene expression; (2) both CO2 and H2O2 interact with daylength and photoreceptor signalling pathways; and (3) cellular signalling pathways may be primed to respond to increased H2O2 in a daylength-determined manner.
Day length is a key regulator of transcriptomic responses to both CO(2) and H(2)O(2) in Arabidopsis.
Specimen part, Treatment
View SamplesWe used Ribo-seq to examine the effect of Myc activation on protein translation in U2OS cells and correalted these changes with alterations in RNA level measured by RNA-seq on tye same conditions. We also examined these effects in the presence of Torin-1, an inhibitor of mTOR Overall design: We measure ribosome occupancy profiles in U2OS cells containing an inducible Myc expression vector that were induced or mock-treated in duplicates for 36 hours. In addition, we repeated the experiments in the presence of Torin-1, an inhibitor of mTOR.
Myc coordinates transcription and translation to enhance transformation and suppress invasiveness.
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View SamplesWe used RNA-seq to examine the effect of Myc activation on U2OS cells transcriptome. We also examined these effects in the presence of Torin-1, an inhibitor of mTOR Overall design: We measure gene expression profiles in U2OS cells containing an inducible Myc expression vector that were induced or mock-treated in duplicates for 36 hours. In addition, we repeated the experiments in the presence of Torin-1, an inhibitor of mTOR.
Myc coordinates transcription and translation to enhance transformation and suppress invasiveness.
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View SamplesWe used GRO-seq to examine the effect of Myc activation on RNA transcription in U2OS cells. Overall design: We measure in duplicates gene transcription rates in U2OS cells containing an inducible Myc expression vector that were induced or mock-treated in duplicates for 5 hours.
Myc coordinates transcription and translation to enhance transformation and suppress invasiveness.
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View SamplesTranscript profiling of transgenic Arabidopsis thaliana seedlings constitutively overexpressing UGT74E2 (35S::UGT74E2).
Perturbation of indole-3-butyric acid homeostasis by the UDP-glucosyltransferase UGT74E2 modulates Arabidopsis architecture and water stress tolerance.
Specimen part
View SamplesAlterations of hydrogen peroxide (H2O2) levels have a profound impact on numerous signaling cascades orchestrating stress responses, plant growth and development, including programmed cell death. To expand the repertoire of known molecular mechanisms implicated in H2O2 signaling, we performed a forward chemical screen to identify small molecules that could alleviate the photorespiratory-induced cell death phenotype of Arabidopsis thaliana mutants lacking H2O2 scavenging capacity by peroxisomal CATALASE2. Here, we report the characterization of pakerine, a m-sulfamoyl benzamide from the sulfonamide family. Pakerine alleviates the cell death phenotype of cat2 mutants exposed to photorespiration-promoting conditions and delays dark-induced senescence in wild type Arabidopsis leaves. By using a combination of transcriptomics, metabolomics and affinity purification we identified ABNORMAL INFLORESCENCE MERISTEM 1 (AIM1) as a putative protein target of pakerine. AIM1 is a 3-hydroxyacyl-CoA dehydrogenase involved in β-fatty acid oxidation that contributes to jasmonic acid (JA) and salicylic acid (SA) biosynthesis. Whereas intact JA biosynthesis was not required for pakerine bioactivity, our results point towards a role for β-oxidation-dependent SA production in execution of H2O2-mediated cell death.
Chemical Genetics Approach Identifies Abnormal Inflorescence Meristem 1 as a Putative Target of a Novel Sulfonamide That Protects Catalase2-Deficient <i>Arabidopsis</i> against Photorespiratory Stress.
Specimen part
View SamplesReactive oxygen species (ROS) are key signalling molecules that regulate growth and development and coordinate responses to biotic and abiotic stresses. ROS homeostasis is controlled through a complex network of ROS production and scavenging enzymes. Recently, the first genes involved in ROS perception and signal transduction have been identified and, currently, we are facing the challenge to uncover the other players within the ROS regulatory gene network. The specificity of ensuing cellular responses depends on the type of ROS and their subcellular production sites. Various experimental systems, including catalase-deficient plants, in combination with genome-wide expression studies demonstrated that increased hydrogen peroxide (H2O2) levels significantly affect the transcriptome of plants and are capable of launching both defence responses and cell death events.
Spatial H2O2 signaling specificity: H2O2 from chloroplasts and peroxisomes modulates the plant transcriptome differentially.
Age, Specimen part
View SamplesDrought is an important environmental factor affecting plant growth and biomass production. Despite this importance, little is known on the molecular mechanisms regulating plant growth under water limiting conditions. The main goal of this work was to investigate, using a combination of growth and molecular profiling techniques, how Arabidopsis thaliana leaves adapt their growth to prolonged mild osmotic stress. Fully proliferating, expanding and mature leaves were harvested from plants grown on plates without (control) or with 25mM mannitol (osmotic stress) and compared to seedlings at stage 1.03.
Developmental stage specificity and the role of mitochondrial metabolism in the response of Arabidopsis leaves to prolonged mild osmotic stress.
Specimen part
View SamplesStresses that target mitochondrial function lead to altered transcriptional responses for 100-1000s of genes genome wide, and are signalled via retrograde communication pathways within the cell. rao2 mutants contain a mutation in the NAC family transcription factor ANAC017 and cannot induce stress responsive genes (such as the mitochondrial alternative oxidase 1a) in response to mitochondrial dysfunction. We sought to define the global gene network regulated through RAO2 function in response to mitochondrial stress (mimicked through treatment of plants with antimycin A - a specific inhibitor of complex III in the mitochondrial electron transfer chain), and non-specific stress signals such as hydrogen peroxide. We have defined global stress responses that are positively and negatively mediated by RAO2 function, and show that greater than 80% of transcripts that are differentially regulated under H2O2 stress require proper functioning of ANAC017 for a normal stress responses.
A membrane-bound NAC transcription factor, ANAC017, mediates mitochondrial retrograde signaling in Arabidopsis.
Treatment
View SamplesHydrogen peroxide (H2O2) can act as a signaling molecule that influences various aspects of plant growth and development, including stress signaling and cell death. Catalase deficient plants are pioneering systems which accumulate hydrogen peroxide (H2O2) from peroxisomal origin during photorespiratory challenges. Respiratory burst oxidase homologues D and F are known to participate in intracellular oxidative stress response launched in cat2 mutants (Chaouch et al., 2012). We studied the compared the transcriptional response of cat2 rbohD and cat2 rbohF double mutants versus the cat2 background to further adress their role during photorespiratory stress.
The ROS Wheel: Refining ROS Transcriptional Footprints.
Age
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