Project description:Plant mitochondria signal to the nucleus leading to altered transcription of nuclear genes by a process called mitochondrial retrograde regulation (MRR). MRR is implicated in metabolic homeostasis and responses to stress conditions. Transcriptional consequences on nuclear gene expression of mitochondrial perturbations were examined by a microarray analyses. Expression of 606 genes was altered by monofluoroacetate (MFA) inhibition of the TCA cycle in leaves of soil grown Arabidopsis plants in the dark for 10 hours. Functional gene category (MapMan) and cluster analyses showed that genes with expression levels affected by perturbation from MFA inhibition were most similarly affected by biotic stresses such as pathogens, not oxidative stresses. Overall, the data provide further evidence for the presence of mtROS-independent MRR signaling, and support the proposed involvement of MRR and mitochondrial function in plant responses to biotic stress. Three independent (bio-replicate) experiments were done using three independent plant samples in the treatments. For each, approximately 30 plants were used for the treated sample and about 30 plants were used as the control sample. Plants were treated with 5 mM monofluoroacetate in 0.01% Tween 20 and incubated in the dark at room temperature (25C) for 6 hours. RNA was isolated from the inhibitor treated and control plants and used for microarray experiments. For each independent (bio-replicate) experiment, two microarrays were utilized using Cy3 and Cy5 dye-labeled samples and dye swapping was incorporated- 2 microarrays for each of 3 independent experiments (6 microarrays total).
Project description:Plant mitochondria signal to the nucleus leading to altered transcription of nuclear genes by a process called mitochondrial retrograde regulation (MRR). MRR is implicated in metabolic homeostasis and responses to stress conditions. Transcriptional consequences on nuclear gene expression of mitochondrial perturbations were examined by a microarray analyses. Expression of 1316 was altered by antimycin A (AA) inhibition of the cytochrome respiratory pathway in leaves of soil grown Arabidopsis plants in the dark for 6 hours. Functional gene category (MapMan) and cluster analyses showed that genes with expression levels affected by perturbation from AA or MFA inhibition were most similarly affected by biotic stresses such as pathogens, not oxidative stresses. Overall, the data provide further evidence for the presence of mtROS-independent MRR signaling, and support the proposed involvement of MRR and mitochondrial function in plant responses to biotic stress. Three independent (bio-replicate) experiments were done using three independent plant samples and independent chemicals in the treatments. For each, approximately 30 plants were used for the treated sample and about 30 plants were used as the control treated sample. Plants were treated with 20 uM antimycin A in 0.01% Tween 20 and incubated in the dark at room temperature (25C) for 6 hours. RNA was isolated from the inhibitor treated and control treated plants and used for microarray experiments. For each independent (bio-replicate) experiment, two microarrays were utilized using Cy3 and Cy5 dye-labeled samples and dye swapping was incorporated- so, minimum of 2 microarrays for each of 3 independent experiments (6 microarrays). In addition, two of the microarrays were duplicated so that a total of 8 slides were used in the data analyses.
Project description:Upon germination, pollen forms a tube that elongates dramatically through female tissues in order to reach and fertilize ovules. While essential for the life cycle of higher plants, the genetic basis underlying most of the process is not well understood. We used Affymetrix Arabidopsis ATH1 Genome Arrays covering more than 80% of the Arabidopsis genome to compare transcriptomes of cell-sorted, hydrated pollen grains with those of flowers, leaves, seedlings and siliques (all samples with duplicates). This comparison revealed that pollen expresses a reduced set of genes with increased proportions of enriched and selectively-expressed transcripts. Relative gene ontology (GO) category representations in pollen and vegetative tissues revealed a functional skew of the pollen transcriptome towards signaling, vesicle transport and cytoskeleton, suggestive of a commitment towards germination and tube growth. Relative gene ontology (GO) category representations in pollen and vegetative tissues reveal a functional skew of the pollen transcriptome towards signaling, vesicle transport and cytoskeleton, suggestive of a commitment towards germination and tube growth. Relative gene ontology (GO) category representations in pollen and vegetative tissues reveal a functional skew of the pollen transcriptome towards signaling, vesicle transport and cytoskeleton, suggestive of a commitment towards germination and tube growth. Gene family and pathway analysis allowed formulation of novel hypotheses for the role of non-classical MADS-box genes, small RNA pathways and cell cycle components in pollen.
Project description:We have implemented an integrated Systems Biology approach to analyze overall transcriptomic reprogramming and systems level defense responses in the model plant Arabidopsis thaliana during an insect (Brevicoryne brassicae) and a bacterial (Pseudomonas syringae pv. tomato strain DC3000) attack. The main aim of this study was to identify the attacker-specific and general defense response signatures in the model plant Arabidopsis thaliana while attacked by phloem feeding aphids or pathogenic bacteria. Defense responses and networks, unique and specific for aphid or Pseudomonas stresses were identified. Our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and thus opened up a new direction to conduct large-scale targeted experiments to explore detailed regulatory links among them. The presented results provide a first comprehensive understanding of Arabidopsis - B. brassicae and Arabidopsis - P. syringae interactions at a systems biology level. Arabidopsis thaliana (ecotype Colombia-0) seeds were grown in 6-cm-diameter pots filled with a sterile soil mix (1.0 part soil and 0.5 part horticultural perlite), 3 plants per pot. Plants were kept in growth chambers VM-CM-6tsch VB 1514 (VM-CM-6tsch Industrietechnik GmbH, Germany) under the following conditions: a 8/16 h (light/dark) photoperiod at 22M-BM-0C/18M-BM-0C, 40%/70% relative humidity, and 70/0 M-NM-<mol m-2s-1 light intensity. After 32 days plants had 8 fully developed leaves. Each plant was infested with 32 wingless aphids [Brevicoryne Brassicae] (4 per leaf), which were transferred to leaves with a fine paintbrush. Infested plants and aphid-free controls were kept in plexiglass cylinders. Plants were harvested 72 h after infestation between the 6th and 8th hour of the light photoperiod. Four biological replicates were prepared from aphid infested and control plants, each sampled from 15 individual plants. Whole rosettes were cut at the hypocotyls and aphids were removed by washing with Milli-Q-filtered water. Differences in transcriptional responses were measured by comparing genes expression of aphid infested plants against non-infested control plants.
Project description:Robust identification of placental PPARg target genes via mutliple PPARg-dependence criteria. Integration of differential expression data from Pparg-null, Rxra-null, Med1-nul and Ncoa6-null placentas and from WT and Pparg-null Trophoblast stem cells (TSC) differentiated for 2 or 4 days in the presence or absence of the PPARg agonist Rosiglitazone (Rosi). [Placentas] Three pools of three WT placentas, each vs a litter-matched pool of three Pparg-null placentas Three pools of three WT placentas, each vs a litter-matched pool of three Rxra-null placentas Three pools of three WT placentas, each vs a litter-matched pool of three Med1-null placentas Three pools of three WT placentas, each vs a litter-matched pool of three Ncoa6-null placentas [Trophoblast stem cells (TSC)] Three independent WT TSC lines differentiated for two and four days in the presence or absence of Rosi vs two independent Pparg-null TSC lines differntiated for the same durations in the presence of Rosi
Project description:We have implemented an integrated Systems Biology approach to analyze overall transcriptomic reprogramming and systems level defense responses in the model plant Arabidopsis thaliana during an insect (Brevicoryne brassicae) and a bacterial (Pseudomonas syringae pv. tomato strain DC3000) attack. The main aim of this study was to identify the attacker-specific and general defense response signatures in the model plant Arabidopsis thaliana while attacked by phloem feeding aphids or pathogenic bacteria. Defense responses and networks, unique and specific for aphid or Pseudomonas stresses were identified. Our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and thus opened up a new direction to conduct large-scale targeted experiments to explore detailed regulatory links among them. The presented results provide a first comprehensive understanding of Arabidopsis - B. brassicae and Arabidopsis - P. syringae interactions at a systems biology level. Arabidopsis thaliana (ecotype Colombia-0) seeds were sown into 6-cm-diameter pots filled with a sterile soil mix (1.0 part soil and 0.5 part horticultural perlite). Plants were kept in growth chambers VM-CM-6tsch VB 1514 (VM-CM-6tch Industrietechnik GmbH, Germany) with a 16/8 h (light/dark) photoperiod at 22/18 M-BM-0C, 40/70% relative humidity, and 70/0 mmol m-2 s-1 light intensity. The Pseudomonas syringae pv. tomato strain DC3000 culture was grown overnight in 10 ml of Kings B solution supplemented with antibiotics rifampicin (50 M-NM-<g mlM-bM-^HM-^R1) and kanamycin (25 M-NM-<g mlM-bM-^HM-^R1). Overnight culture was washed once in 10 mM MgCl2 and final cell densities were adjusted to approximately 0.20 at 600 nm (approximately 1.5 M-CM-^W 108 cfu mlM-bM-^HM-^R1) in 10 mM MgCl2. Plants were mock-challenged with 10 mM MgCl2 or inoculated with DC3000 strain, 3-4 leaves were infiltrated on the abaxial surface with a needleless 1-ml syringe.Whole rosettes were cut at the hypocotyls and harvested from Pseudomonas infested and mock-infected plants after 72 hours treatment. 4 biological replicates were prepared from each treatment, each containing rosettes from 15 individual plants. Differences in transcriptional responses were measured by comparing genes expression of Pseudomonas infected plants against mock-infected control plants.
Project description:Comparison of females mated to males null for Sex-Peptide (SP0, Liu, H. and E. Kubli, Sex-peptide is the molecular basis of the sperm effect in Drosophila melanogaster. Proc Natl Acad Sci U S A, 2003. 100(17): p. 9929-33) or to control, Sex-Peptide producing, males. Comparisons were made at 3 and 6 hours after mating, in dissected Head-Thorax body parts.
Project description:Comparison of females mated to males null for Sex-Peptide (SP0, Liu, H. and E. Kubli, Sex-peptide is the molecular basis of the sperm effect in Drosophila melanogaster. Proc Natl Acad Sci U S A, 2003. 100(17): p. 9929-33) or to control, Sex-Peptide producing, males. Comparisons were made at 3 and 6 hours after mating, in dissected Abdomen parts.<br>
Project description:Constitutive heterochromatin comprising the centromeric and telomeric parts of chromosomes includes DNA marked by high levels of methylation associated with histones modified by repressive marks. These epigenetic modifications silence transcription and ensure stable inheritance of this inert state. Although, environmental cues can alter epigenetic marks and lead to modulation of the transcription of genes located in euchromatic parts of the chromosomes, there is no evidence that external stimuli can globally destabilize silencing of constitutive heterochromatin. We have found that heterochromatin-associated silencing in Arabidopsis plants subjected to a particular temperature regime is released in a genome-wide manner. This occurs without alteration of repressive epigenetic modifications and does not involve common epigenetic mechanisms. Such induced release of silencing is mostly transient and rapid restoration of the silent state occurs without the involvement of factors known to be required for silencing initiation. Thus, our results reveal new regulatory aspects of transcriptional repression in constitutive heterochromatin and open up possibilities to identify the molecular mechanisms involved. 4 samples: CTS, ITS, CTS+2d, IST+2d with 3 replicates each
Project description:Pattern recognition receptors (PRRs) at the plasma membrane promote plant immunity through the detection of conserved microbe-associated molecular patterns (MAMPs). In plants, the PRR for bacterial flagellin (flg22) is encoded by the receptor kinase FLS2. One of the earliest MAMP responses is the rapid and transient increase of cytosolic calcium (Ca2+) ions, which is required for many of the well-described downstream responses, e.g. generation of reactive oxygen species (ROS) and the transcriptional activation of defence-associated genes. Despite its relevance, the molecular components regulating the Ca2+ burst remain largely unknown. Here, we show that the plasma membrane P2B-type Ca2+ ATPase ACA8 forms a dynamic complex with the PRR FLS2. ACA8 and its closest homologue ACA10 are required for immunity against virulent bacteria. Mutant aca8 aca10 plants are reduced in the flg22-induced Ca2+ burst, show reduced ROS production and exhibit altered transcriptional reprogramming. In particular, flg22-induced gene expression is elevated downstream of signalling mitogen-activated protein (MAP) kinases, but reduced downstream of the calcium-dependent protein (CDP) kinase cascade. These results demonstrate that the fine regulation of Ca2+ fluxes in the cytosol is critical for the coordination of the downstream MAMP responses and provide for the first time a link between the FLS2 receptor complex and signalling kinases via the secondary messenger Ca2+. ACA8 also interacted with the BRI1 and CLV1 receptor kinases, which correlated with the developmental phenotypes of aca8 aca10 mutants suggesting a broader role for Ca2+ ATPases in receptor-mediated signalling. We used Affymetrix Arabidopsis Tiling 1.0R Array to compare global transcript levels in 7 days-old sterile grown seedlings. Steady-state mRNA levels in total RNA samples of 7 days old sterile seedlings