Project description: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.
Project description: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. Two genotypes x five conditions experiment, including Arabidopsis Col0WT and cat2-1 plants grown in soil for 5 weeks in a 8h light/16h dark (short day) regime at high CO2 concentration (3000 ppm CO2) and subsequently transferred to air (400 ppm CO2) in a short day or long day (16h light/8h dark) regime for 2 and 4 days. Three biological replicates were used that consist each of a pool of two leaves from different plants. Each sample was hybridized to one Genechip® Arabidopsis ATH1 Genome Array (Affymetrix).
Project description:Reactive 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. We used microarrays to assess differential gene expression provoked by H2O2 from plastid or peroxisomal origin, respectively. Columbia-0 (Col-0, wild type), catalase-deficient Salk plants (10-15% of wild-type catalase activity; cat2-2; N576998; (Queval et al., 2007)) and A. thaliana plants expressing glycolate oxidase in chloroplasts (GO5 plants; (Fahnenstich et al., 2008)) were grown in soil under a 16h light/8h dark regime at photosynthetically active photon flux densities (PPFD) of 75 µmol quanta m-2 s-1 at 22°C day/18°C night temperatures and a CO2 concentration of 3,000 ppm. After three weeks of growth, plants were transferred to ambient CO2 concentration (380 ppm) and the same PPFD. Whole rosettes were harvested at 0h and 8h after transfer. Control samples were harvested at 8 h from plants continuously maintained in high CO2.
Project description:Extracellular adenosine 5’-triphosphate (ATP) is a signaling molecule. To define the global transcriptional response to ATP, we performed DNA microarray analysis using RNA derived from wild-type (Col-0) Arabidopsis and the dorn1-1 mutant, Lectin receptor kinase I.9 (At5g60300) carrying a EMS point mutation, seedlings after 100 μM ATP.
Project description:Col-0 floral stem was grafted on the msh1 mutant (Col-0/msh1); on the dcl2,3,4,msh1 quadruple mutant (Col-0/dcl2,3,4,msh1); on Col-0 (Col-0/Col-0). Seeds were collected from the grafted Col-0 scion after grafts were established. Seed coming from the graft then were grown on the peat mix, leaf tissue was collected at the bolting and used for the total RNA sequencing.
Project description:Col-0 floral stem was grafted on the msh1 mutant (Col-0/msh1); on the dcl2,3,4,msh1 quadruple mutant (Col-0/dcl2,3,4,msh1); on Col-0 (Col-0/Col-0). Seeds were collected from the grafted Col-0 scion after grafts were established. Seed coming from the graft then were grown on the peat mix, leaf tissue was collected at the bolting and used for the bisulfite sequencing (methylome). Tissue from the msh1 mutant and dcl2,3,4,msh1 quadruple mutants used as rootstocks was similarly collected at the bolting stage and used for the bisulfite sequencing.
Project description:rs12-08_cyp715a1 - col-0 vs cyp715a1 - The microarray analysis is part of a project aimed at characterizing the function of the cytochrome P450 CYP715A1 in Arabidopsis thaliana. - Flower buds of Arabidopsis Col-0 (wild-type) and cyp715A1 mutant were harvested for a comparative analysis of their transcriptomes.
Project description:Col-0 floral stem was grafted on the msh1 mutant (Col-0/msh1) and on the dcl2,3,4,msh1 quadruple mutant (Col-0/dcl2,3,4,msh1). Seeds were collected from the grafted Col-0 scion after grafts were established. Seed coming from the graft then were grown on 0.5M MS growth medium and root tissue was collected after 12 days and used for the RNA sequencing.
Project description:Differentially regulated genes in rosette leaves and roots of hydroponically grown Arabidopsis thaliana Col-0 and nrt1.5-5 mutant plants were identified by microarray analyses.