Arabidopsis mutants treated with flg22, Alternaria brassicicola, Methyl jasmonate and Pst DC3000 bacteria
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE17464 | GEO | 2010/01/15
SECONDARY ACCESSION(S): PRJNA118743
REPOSITORIES: GEO
Similar Datasets
Project description:Gibberellin (GA) promotes plant growth by destabilizing DELLA proteins. DELLA proteins integrate multiple hormonal and environmental stress responses. We investigated the role of GA and DELLA proteins in plant defence. We used microarrays to detail the global programme of gene expression controlled by DELLA proteins and identified distinct classes of differentially regulated genes in response to pathogens, hormones or pathogen elicitors. Experiment Overall Design: Five weeks old short day grown Arabidopsis leaf discs were used to treat with flg22 and samples were collected after 1 hour and 2 hour time points. For Alternaria brassicicola, five weeks old plants were drop inoculated with 4x 5µl droplets of Alternaria brassicicola spores (5x105 spores/ml) and samples were collected 3 days post inoculation. Five weeks old plants were infiltrated with Pst DC3000 (2x105cfu/ml) bacteria and samples were collected after 12 hours post infiltration. For methyl jasmonate treatments, five weeks old plants were sprayed with 10µM Methyl Jasmonate solution, covered with plastic bags and samples were collected after one hour.
2010-03-02 | E-GEOD-17464 | biostudies-arrayexpress
Project description:DELLA proteins are members of the GRAS-domain family of transcriptional regulators and modulate transcriptional activity through protein-protein interactions with at least 15 different classes of transcription factor. The plant hormone gibberellin (GA) regulates a range of growth and development responses including promoting cell elongation, by triggering the degradation of DELLA proteins. More than 70% of modern wheat (Triticum aestivum L.) varieties carry alleles encoding DELLA proteins that are resistant to GA-mediated degradation. These alleles result in constitutive growth repression in stem tissues and confer a semi-dwarf growth habit associated with improved lodging resistance. However, these alleles also have negative pleiotropic effects such as reduced nitrogen use efficiency and weak early vigour that restrict their utility in some environments. A detailed understanding of the mechanisms by which DELLA proteins regulate growth and development will be necessary to dissect these responses and develop targeted strategies to breed improved crop varieties. We identified the orthologous C2H2 Zinc-finger transcription factors INDETERMINATE DOMAIN 5 (IDD5) in wheat and SEMI-DWARF3 (SDW3) in barley (Hordeum vulgare) as positive regulators of stem and leaf expansion. Both IDD5 and SDW3 physically interact with DELLA proteins and are epistatic to these genes. We propose a mechanism by which IDD proteins integrate GA signals to modulate downstream gene transcriptional activity through a protein complex dual activation and repression activities. Changes in GA biosynthesis gene expression levels suggest that part of this response involves GA homeostasis. Plants carrying null mutations in IDD5 and SDW3 exhibit a GA-insensitive semi-dwarf growth habit comparable to the Rht-D1b ‘Green Revolution’ allele and have potential as novel dwarfing alleles in cereal breeding programmes.
2024-11-30 | GSE282829 | GEO
Project description:This model is from the article:
Mathematical modeling elucidates the role of transcriptional feedback in gibberellin signaling.
Middleton AM , Úbeda-Tomás S , Griffiths J , Holman T , Hedden P , Thomas SG , Phillips AL , Holdsworth MJ , Bennett MJ , King JR, Owen MR Proc. Natl. Acad. Sci. U.S.A.
2012 May; 109(19): 7571-6 22523240
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Abstract:
The hormone gibberellin (GA) is a key regulator of plant growth. Many of the components of the gibberellin signal transduction [e.g., GIBBERELLIN INSENSITIVE DWARF 1 (GID1) and DELLA], biosynthesis [e.g., GA 20-oxidase (GA20ox) and GA3ox], and deactivation pathways have been identified. Gibberellin binds its receptor, GID1, to form a complex that mediates the degradation of DELLA proteins. In this way, gibberellin relieves DELLA-dependent growth repression. However, gibberellin regulates expression of GID1, GA20ox, and GA3ox, and there is also evidence that it regulates DELLA expression. In this paper, we use integrated mathematical modeling and experiments to understand how these feedback loops interact to control gibberellin signaling. Model simulations are in good agreement with in vitro data on the signal transduction and biosynthesis pathways and in vivo data on the expression levels of gibberellin-responsive genes. We find that GA-GID1 interactions are characterized by two timescales (because of a lid on GID1 that can open and close slowly relative to GA-GID1 binding and dissociation). Furthermore, the model accurately predicts the response to exogenous gibberellin after a number of chemical and genetic perturbations. Finally, we investigate the role of the various feedback loops in gibberellin signaling. We find that regulation of GA20ox transcription plays a significant role in both modulating the level of endogenous gibberellin and generating overshoots after the removal of exogenous gibberellin. Moreover, although the contribution of other individual feedback loops seems relatively small, GID1 and DELLA transcriptional regulation acts synergistically with GA20ox feedback.
2024-09-02 | BIOMD0000000422 | BioModels
Project description:Plant microRNAs (miRNAs) have been implicated in plant immunity. These mainly focusing Arabidopsis thaliana threatened by (hemi-)biotrophic pathogens such as the bacterial pathogen Pseudomonas syringae. Here, we show that the Arabidopsis miRNA pathway is important for defense responses against the necrotrophic fungus Alternaria brassicicola. The miRNA pathway mutant ago1 exhibits an exaggerated response when treated with A. brassicicola, proposing that AGO1 is positive regulator. We found a subset of Arabidopsis miRNAs that quickly change their expression and their abundance in AGO1 complexes in plants exposed to A. brassicicola. The miRNAs responding to pathogen treatment are mainly targeting genes encoding metabolic enzymes, proteins involved protein degradation or transposons. In case of miR163, A. brassicicola infection results in increased levels of miRNA precursors and preferential accumulation of an unspliced form of pri-miR163, suggesting that A. brassicicola infection changes the transcriptional and post-regulation of pri-miRNAs. miR163 acts as a negative regulator of plant defense because mir163 mutants are more resistant when treated with A. brassicicola. Taken together, our results reveal the existence of positively and negatively acting Arabidopsis miRNA modulating the defense responses against A. brassicicola and highlight the importance of host miRNAs in the interaction between plants and necrotrophic pathogens.
2019-06-17 | GSE83478 | GEO
Project description:Plant microRNAs (miRNAs) have been implicated in plant immunity. These mainly focusing Arabidopsis thaliana threatened by (hemi-)biotrophic pathogens such as the bacterial pathogen Pseudomonas syringae. Here, we show that the Arabidopsis miRNA pathway is important for defense responses against the necrotrophic fungus Alternaria brassicicola. The miRNA pathway mutant ago1 exhibits an exaggerated response when treated with A. brassicicola, proposing that AGO1 is positive regulator. We found a subset of Arabidopsis miRNAs that quickly change their expression and their abundance in AGO1 complexes in plants exposed to A. brassicicola. The miRNAs responding to pathogen treatment are mainly targeting genes encoding metabolic enzymes, proteins involved protein degradation or transposons. In case of miR163, A. brassicicola infection results in increased levels of miRNA precursors and preferential accumulation of an unspliced form of pri-miR163, suggesting that A. brassicicola infection changes the transcriptional and post-regulation of pri-miRNAs. miR163 acts as a negative regulator of plant defense because mir163 mutants are more resistant when treated with A. brassicicola. Taken together, our results reveal the existence of positively and negatively acting Arabidopsis miRNA modulating the defense responses against A. brassicicola and highlight the importance of host miRNAs in the interaction between plants and necrotrophic pathogens.
2019-06-17 | GSE83487 | GEO
Project description:Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Molecular determinants of its life style shift between saprophyte and pathogen, however, are unknown. To identify these determinants we studied nonpathogenic mutants of a transcription factor-coding gene, AbPf2. Frequency and timing of germination and appressorium formation on host plants were similar between the nonpathogenic Δabpf2 mutants and wild-type A. brassicicola. The mutants were also similar in vitro to wild-type A. brassicicola in vegetative growth, conidium production, and responses to chemical stressors, such as a phytoalexin, reactive oxygen species, and osmolites. The mutants, however, did not penetrate host plant tissues, though their hyphae continued to grow on the plant surface. Transcripts of the AbPf2 gene increased exponentially soon after wild-type conidia encountered their host plants. A small amount of AbPf2 protein, monitored by fused green fluorescent protein, was located in both the cytoplasm and nuclei of young, mature conidia. The protein level decreased during saprophytic growth but increased several-fold during pathogenesis. Levels of both the proteins and transcripts sharply declined following colonization of host tissues beyond the initial infection site. When the transcription factor was expressed at an induced level in the wild type during early pathogenesis, the expression of 106 fungal genes was down-regulated in the Δabpf2 mutants. Notably, 33 of the 106 genes encoded secreted proteins, including eight putative effector proteins. Plants inoculated with Δabpf2 mutants expressed higher levels of genes associated with photosynthesis, the pentose phosphate pathway, and primary metabolism, but lower levels of defense-related genes. Our results suggest that conidia of A. brassicicola are programmed as saprophytes, but become parasites upon contact with their hosts. AbPf2 coordinates this transformation by expressing pathogenesis-associated genes, including those coding for effectors.
2013-09-30 | GSE38984 | GEO
Project description:Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Molecular determinants of its life style shift between saprophyte and pathogen, however, are unknown. To identify these determinants we studied nonpathogenic mutants of a transcription factor-coding gene, AbPf2. Frequency and timing of germination and appressorium formation on host plants were similar between the nonpathogenic Δabpf2 mutants and wild-type A. brassicicola. The mutants were also similar in vitro to wild-type A. brassicicola in vegetative growth, conidium production, and responses to chemical stressors, such as a phytoalexin, reactive oxygen species, and osmolites. The mutants, however, did not penetrate host plant tissues, though their hyphae continued to grow on the plant surface. Transcripts of the AbPf2 gene increased exponentially soon after wild-type conidia encountered their host plants. A small amount of AbPf2 protein, monitored by fused green fluorescent protein, was located in both the cytoplasm and nuclei of young, mature conidia. The protein level decreased during saprophytic growth but increased several-fold during pathogenesis. Levels of both the proteins and transcripts sharply declined following colonization of host tissues beyond the initial infection site. When the transcription factor was expressed at an induced level in the wild type during early pathogenesis, the expression of 106 fungal genes was down-regulated in the Δabpf2 mutants. Notably, 33 of the 106 genes encoded secreted proteins, including eight putative effector proteins. Plants inoculated with Δabpf2 mutants expressed higher levels of genes associated with photosynthesis, the pentose phosphate pathway, and primary metabolism, but lower levels of defense-related genes. Our results suggest that conidia of A. brassicicola are programmed as saprophytes, but become parasites upon contact with their hosts. AbPf2 coordinates this transformation by expressing pathogenesis-associated genes, including those coding for effectors. Twenty seven Ar. thaliana (Col-0) were spray-inoculated until run-off with 5x105 conidia per milliliter of Δabpf2-5 mutant or the wild type. Tissues containing both host plant tissue and fungal hyphae were harvested at 12 hours postinoculation and 48 hours postinoculation from three plants for each sample and immediately frozen in liquid nitrogen to fix gene expression profiles. The frozen tissues were ground and total RNA was extracted using an RNeasy kit. Residual DNA was digested in columns with RNase-free DNase following the manufacturer’s protocol (Qiagen, Palo Alto, CA). Three biological replicates were prepared for the mutant and three for the wild type and their gene expression profiles compared. We constructed strand-specific sequencing libraries using the TruSeq™ RNA Sample Prep Kit (Illumina, San Diego, CA) from total RNA following the manufacturer’s protocol. Each sample RNA was used to construct a library with a unique index primer. A total of six index primers were used to construct six libraries. All six libraries were mixed and determined 100 nucleotide-long sequence tags using Illumina Hiseq2000 (Illumina, San Diego, CA, USA) according to the manufacturer’s protocol. Image analysis, base-calling, and quality checks were performed with the Illumina data analysis pipeline CASAVA v1.8.0.
2013-09-30 | E-GEOD-38984 | biostudies-arrayexpress
Project description:The hormones gibberellins (GA) control many aspects of plant growth and development thruough the whole life cycle of the plant. For instance, GA participate in the establishment of the skotomorphogenic developmental program that is triggered when seeds germinate in darkness, i.e. under the soil. Under these conditions seedlings appear etiolated and developmental features usually triggered by light are kept repressed. The GA signaling elements GAI and RGA have a major, partially redundant role in this process. These proteins belong to the DELLA family of transcriptional regulators and are destabilized by GA, acting as negative regulators of the pathway. In order to understand the molecular basis of the regulation of the skotomorphogenesis by GA, we sought to identify early target genes of the activity of GAI in etiolated seedlings. For that purpose we analyzed rapid, global changes in gene expression in response to a transient accummulation of a dominant version of GAI, gai-1, which is resistant to GA-induced destabilization.
2011-09-01 | GSE24253 | GEO
Project description:GA treatment of wild-type rice and use of DELLA protein mutant for RNA-seq and ChIP-seq. Explaining the chromatin mechanisms of DELLA-mediated gene repression and GA signalling-induced gene activation.
2023-08-11 | GSE226812 | GEO