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:In plants, epidermal guard cells integrate and respond to numerous environmental signals to control stomatal pore apertures thereby regulating gas exchange. Chromatin structure controls transcription factor access to the genome, but whether large-scale chromatin remodeling occurs in guard cells during stomatal movements, and in response to the hormone abscisic acid (ABA) in general, remain unknown. Here we isolate guard cell nuclei from Arabidopsis thaliana plants to examine whether the physiological signals, ABA and CO2, regulate guard cell chromatin during stomatal movements. Our cell type specific analyses uncover patterns of chromatin accessibility specific to guard cells and define novel cis-regulatory sequences supporting guard cell specific gene expression. We find that ABA triggers extensive and dynamic chromatin remodeling in guard cells, roots, and mesophyll cells with clear patterns of cell-type specificity. DNA motif analyses uncover binding sites for distinct transcription factors enriched in ABA-induced and ABA-repressed chromatin. We identify the ABF/AREB bZIP-type transcription factors that are required for ABA-triggered chromatin opening in guard cells and implicate the inhibition of a set of bHLH-type transcription factors in controlling ABA-repressed chromatin. Moreover, we demonstrate that ABA and CO2 induce distinct programs of chromatin remodeling. We provide insight into the control of guard cell chromatin dynamics and propose that ABA-induced chromatin remodeling primes the genome for abiotic stress resistance.
Project description:In plants, epidermal guard cells integrate and respond to numerous environmental signals to control stomatal pore apertures thereby regulating gas exchange. Chromatin structure controls transcription factor access to the genome, but whether large-scale chromatin remodeling occurs in guard cells during stomatal movements, and in response to the hormone abscisic acid (ABA) in general, remain unknown. Here we isolate guard cell nuclei from Arabidopsis thaliana plants to examine whether the physiological signals, ABA and CO2, regulate guard cell chromatin during stomatal movements. Our cell type specific analyses uncover patterns of chromatin accessibility specific to guard cells and define novel cis-regulatory sequences supporting guard cell specific gene expression. We find that ABA triggers extensive and dynamic chromatin remodeling in guard cells, roots, and mesophyll cells with clear patterns of cell-type specificity. DNA motif analyses uncover binding sites for distinct transcription factors enriched in ABA-induced and ABA-repressed chromatin. We identify the ABF/AREB bZIP-type transcription factors that are required for ABA-triggered chromatin opening in guard cells and implicate the inhibition of a set of bHLH-type transcription factors in controlling ABA-repressed chromatin. Moreover, we demonstrate that ABA and CO2 induce distinct programs of chromatin remodeling. We provide insight into the control of guard cell chromatin dynamics and propose that ABA-induced chromatin remodeling primes the genome for abiotic stress resistance.
Project description:To identify genes of the guard cell transcriptome of Arabidopsis thaliana enriched guard cell samples were compared with total leaf tissue. Genes of the abscisic acid and humidity response of Arabidopsis thaliana guard cells were identified by treatment with ABA-Spray and low humidity. total samples analysed are 24: 4 biological independent replicates of: total leaf (COL-0) vs. enriched guard cells (COL-0); ABA-sprayed enriched guard cells (gl1-1) vs. control-sprayed enriched guard cells (gl1-1); low humidity (20%rh) treated enriched guard cells (COL-0) vs. high humidity (80%) treated enriched guard cells (COL-0)
Project description:To identify genes of the guard cell transkriptome of Arabidopsis thaliana enriched guard cell samples were compared with total leaf tissue. Genes of the abscisic acid and humidity response of Arabidopsis thaliana guard cells were identified by treatment with ABA-Spray and low humidity. Ost1-2 and slac1-3 mutants were compared to their wildtype. total samples analysed are 35: 4 biolocigal independent replicates of: total leaf (COL-0) vs. enriched guard cells (COL-0); ABA-sprayed enriched guard cells (gl1-1) vs. control-sprayed enriched guard cells (gl1-1); enriched guard cells (slac1-3) vs. enriched guard cells (gl1-1);guard cells (ost1-2) vs. guard cells (ler);low humidity(20%rh) treated enriched guard cells (COL-0) vs. high humidity(80%) treated enriched guard cells (COL0)
Project description:To identify genes of the guard cell transcriptome of Arabidopsis thaliana enriched guard cell samples were compared with total leaf tissue. Genes of the abscisic acid and humidity response of Arabidopsis thaliana guard cells were identified by treatment with ABA-Spray and low humidity.
Project description:To identify genes of the guard cell transkriptome of Arabidopsis thaliana enriched guard cell samples were compared with total leaf tissue. Genes of the abscisic acid and humidity response of Arabidopsis thaliana guard cells were identified by treatment with ABA-Spray and low humidity. Ost1-2 and slac1-3 mutants were compared to their wildtype.
Project description:Heterotrimeric G proteins mediate crucial and diverse signaling pathways in eukaryotes. To gain insights into the regulatory modes of the G protein and the co-regulatory modes of the G protein and the stress hormone abscisic acid (ABA), we generated and analyzed gene expression in G protein subunit single and double mutants of the model plant Arabidopsis thaliana. Through a Boolean modeling approach, our analysis reveals novel modes of heterotrimeric G protein action. Keywords: transcriptome analysis; G protein subunit mutants; abscisic acid (ABA) Microarray data were generated from four genotypes (wild type, gpa1-4 mutant, agb1-2 mutant, agb1-2 gpa1-4 double mutant) with or without ABA treatment. Arabidopsis plants were grown in growth chambers with an 8 hr light/16hr dark. Three hundred Arabidopsis leaves excised from 60-70 five-week-old plants were used as the starting material for each guard cell microarray. Ten mature leaves taken from 3-4 plants grown side-by side with the plants for guard cell isolation were used for each leaf sample. Excised leaf and isolated guard cell samples were treated with ABA (50 μM) or EtOH (solvent control) for 3 hrs. For each type of sample (guard cells or leaves), three independent biological replicates were performed, resulting in a total of 48 microarray hybridizations (2 sample types ´ 4 genotypes ´ two treatments ´3 replicates).
Project description:Chloroplast-nuclear retrograde signaling is viewed as a mechanism for inter-organelle communication. Here we show the SAL1-PAP (3′-phosphoadenosine 5′- phosphate) retrograde pathway functions more broadly in guard cells, interacting with abscisic acid (ABA) signaling at least in part via exoribonucleases. Unexpectedly, PAP bypasses the canonical signaling components ABA Insensitive 1 (ABI1) and Open Stomata 1 (OST1) by priming an alternative pathway that restores ABA-responsive gene expression, ROS bursts, ion channel function and stomatal closure in ost1-2. This alternative pathway up-regulates lowly expressed Calcium Dependent Protein Kinases (CDPKs) which have the capacity to activate the key slow anion channel SLAC1 in response to ABA-mediated and ost1-2 independent calcium release. The role of PAP in priming an alternative pathway to bypass components previously considered essential for stomatal closure demonstrates how a chloroplast signal can have broader roles as a secondary messenger to directly intersect with and tune hormone signaling.