Transcription profiling of Arabidopsis thaliana auxin resistant axr4 mutant and wild type Col-0
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
SUBMITTER: unknown unknown
PROVIDER: E-NASC-39 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:The plant hormone auxin represents an important regulator of growth and development. Significant insight into the mechanisms of auxin action have been obtained from studies of auxin resistant mutants such as aux1 and axr3. The Arabidopsis axr4 mutant was identified in a screen for auxin resistant root growth. In addition to the root growth of axr4 being resistant to exogenous auxin, there is also a 50% reduction in the number of lateral roots that form. The double axr4/aux1 mutant shows an additive effect in reducing lateral root numbers to 10% of wild-type. Gaining further information about the potential interaction between AUX1 and AXR4 may provide important insight into auxin regulated plant growth. Mapping experiments have placed the AXR4 gene on the lower arm of chromosome 1 between the ch1 and le markers (Hobbie and Estelle 1995). However, the AXR4 gene remains to be cloned. Identifying the AXR4 gene will help in elucidating the function of the protein. A transcript analysis of axr4 mutant seedlings will be used in 2 ways. Firstly, the transcription level of genes in the locality of the axr4 map position will be examined to identify those which are absent or significantly reduced in axr4 compared to the Col0 control. If the lesion causing the axr4 mutation results in a highly unstable mRNA or abolishes transcription then the signal will be dramatically reduced. Potential candidate genes identified in this way will be further analysed using a combination of RT-PCR and sequencing to identify the AXR4 gene. Secondly, the transcriptomics data obtained from axr4 and Col0 will be compared to identify genes which show significant transcript level differences and therefore represent targets for either direct or indirect regulation by AXR4. Hobbie, L. and Estelle, M. (1995) The axr4 auxin-resistant mutants of Arabidopsis thaliana define a gene important for root gravitropism and lateral root initiation. Plant J. 7 211-220 Experiment Overall Design: 2 samples
2008-06-14 | E-GEOD-6168 | biostudies-arrayexpress
Project description:Background: The Arabidopsis ANR1 gene is a key regulator of root architecture (Zhang and Forde, 1998): when ANR1 is down-regulated (by antisense or co-suppression) the resulting lines are no longer able to proliferate their lateral roots in response to localised supplies of NO3- (Zhang and Forde, 1998). ANR1 encodes a root-specific member of the MADS box family of transcription factors and is thought to be a component of a signalling pathway that links an external NO3- signal to increased meristematic activity in the lateral root meristem (Zhang et al., 1999).A major goal of our present BBSRC-funded project is to learn more about this NO3- response pathway by identifying the downstream targets of ANR1. To this end we have generated a set of transgenic lines in which ANR1 is under a novel post-translational control. This was achieved by tagging ANR1 with the steroid-binding domain of the rat glucocorticoid receptor (rGR) and expressing the fusion protein under the control of the CaMV 35S promoter. Initial results with these lines confirm that the architecture of the root system is altered in a way that correlates with the presence of the steroid inducer (dexamethasone, or DEX) and the expression of the ANR1::rGR transgene. We now wish to apply transcript analysis to one of these lines (ANGR4-12) to identify the genes whose expression is up- or down-regulated by ANR1. Sablowski and Meyerowitz (1998) successfully used an analogous approach to identify a gene that is an immediate target of the AP3 MADS-box transcription factor (although here, in the absence of microarray technology, differential display was used). Experimental: Plants of the two genotypes (ANGR4-12 and wild type) will be grown in sterile liquid culture for 3-4 weeks and then starved of N for 3 d (to quench the endogenous NO3- signalling pathway) before starting the DEX treatment. Roots will be harvested after 60 min from roots of DEX-treated and mock-treated RGR4-12 and control plants (four RNA samples). To minimise background noise due to environmental variables we will repeat the experiment three times and pool the RNA samples.
2022-11-21 | E-NASC-25 | biostudies-arrayexpress
Project description:The aim of this study is to identify genes differentially expressed during the transition between dormancy and activity in axillary shoot apical meristems. We have chosen to study this by comparing mRNA populations from the axillary buds of the auxin over-responding, apically dominant axr3-1 mutant of Arabidopsis,with those from the axillary buds of the auxin resistant axr1-12 bushy mutant. Preliminary investigation using cDNA AFLP has been successful in identifying differentially expressed transcripts in the buds of these two genotypes, thus demonstrating the importance of this study, however this is a time consuming procedure. Axillary buds from axr3-1 are seen to arrest at an early stage when the buds are approximately 2mm long and harvested at this point. Buds of a similar size were harvested from axr1-12 plants and the RNA extracted using Qiagen columns.These two mRNA samples will represent the dormant and active buds to be comparedin this experiment. The plants from which these buds were harvested were grown in adjacent p40 trays in a plant growth room. Between two and three buds were harvested from each plant.
2003-10-20 | E-NASC-10 | biostudies-arrayexpress
Project description:The aim of this study is to identify genes differentially expressed during the transition between dormancy and activity in axillary shoot apical meristems. We have chosen to study this by comparing mRNA populations from the axillary buds of the auxin over-responding, apically dominant axr3-1 mutant of Arabidopsis,with those from the axillary buds of the auxin resistant axr1-12 bushy mutant. Preliminary investigation using cDNA AFLP has been successful in identifying differentially expressed transcripts in the buds of these two genotypes, thus demonstrating the importance of this study, however this is a time consuming procedure. Axillary buds from axr3-1 are seen to arrest at an early stage when the buds are approximately 2mm long and harvested at this point. Buds of a similar size were harvested from axr1-12 plants and the RNA extracted using Qiagen columns.These two mRNA samples will represent the dormant and active buds to be comparedin this experiment. The plants from which these buds were harvested were grown in adjacent p40 trays in a plant growth room. Between two and three buds were harvested from each plant. Experimenter name: Sally Ward; Experimenter phone: 01904 328683; Experimenter fax: 01904 328682; Experimenter institute: University of York; Experimenter address: Dept of Biology (Area 11),; University of York,; Heslington,; York; Experimenter zip/postal_code: YO10 5DD; Experimenter country: UK Experiment Overall Design: 2 samples were used in this experiment
2008-06-11 | E-GEOD-10324 | biostudies-arrayexpress
Project description:Background: The Arabidopsis ANR1 gene is a key regulator of root architecture (Zhang and Forde, 1998): when ANR1 is down-regulated (by antisense or co-suppression) the resulting lines are no longer able to proliferate their lateral roots in response to localised supplies of NO3- (Zhang and Forde, 1998). ANR1 encodes a root-specific member of the MADS box family of transcription factors and is thought to be a component of a signalling pathway that links an external NO3- signal to increased meristematic activity in the lateral root meristem (Zhang et al., 1999).A major goal of our present BBSRC-funded project is to learn more about this NO3- response pathway by identifying the downstream targets of ANR1. To this end we have generated a set of transgenic lines in which ANR1 is under a novel post-translational control. This was achieved by tagging ANR1 with the steroid-binding domain of the rat glucocorticoid receptor (rGR) and expressing the fusion protein under the control of the CaMV 35S promoter. Initial results with these lines confirm that the architecture of the root system is altered in a way that correlates with the presence of the steroid inducer (dexamethasone, or DEX) and the expression of the ANR1::rGR transgene. We now wish to apply transcript analysis to one of these lines (ANGR4-12) to identify the genes whose expression is up- or down-regulated by ANR1. Sablowski and Meyerowitz (1998) successfully used an analogous approach to identify a gene that is an immediate target of the AP3 MADS-box transcription factor (although here, in the absence of microarray technology, differential display was used). Experimental: Plants of the two genotypes (ANGR4-12 and wild type) will be grown in sterile liquid culture for 3-4 weeks and then starved of N for 3 d (to quench the endogenous NO3- signalling pathway) before starting the DEX treatment. Roots will be harvested after 60 min from roots of DEX-treated and mock-treated RGR4-12 and control plants (four RNA samples). To minimise background noise due to environmental variables we will repeat the experiment three times and pool the RNA samples. Experiment Overall Design: Number of plants pooled:20 Experiment Overall Design: Biological replicates: 2
2008-06-14 | E-GEOD-6155 | biostudies-arrayexpress
Project description:Background Heterodera schachtiia is an economically important plant parasitic nematode that forms a syncytium from a cell superficial to the formed vascular bundle by progressive recruitment of other cells into the structure. The pattern of plant gene expression changes dramatically inside the syncytium. The pathogen probably plays a major role in defining the plant response by choice of initial plant cell during precise behaviour in planta and/or by the secretions it releases. The modified plant cells enable a high feeding rate by the female nematode so enhancing its rate of development and subsequent daily egg production. Arabidopsis is widely used as a model plant to characterise molecular responses to nematodes (e.g. Sijmons et al., 1991 Plant J. 1:245-254.). A complete overview of the changes in plant gene expression when sedentary nematodes establish has not yet been gained using Arabidopsis or any other host plant. Experimental Approaches Our initial studies will focus on the H. schachtii/Arabidopsis interaction. To assure reliable microarray screening care has been taken to minimise extraneous differences between samples (see "Growth conditions" section). At 21 days (Growth stage 3.2-3.5 Boyes et al., 2001 Plant Cell 13:1499-1510) Arabidopsis plants were challenged with rigorously sterilised, infective nematodes of H. schachtii as before (Urwin et al., (1997) Plant Journal 12: 455-461.). 35 sterile J2s were pipetted onto small ~0.5mm2 squares of sterile GF/A filter paper. The GF/A paper was left in direct contact with the zone of elongation on 3 lateral roots per plant for 48 hours. Control plants were mock inoculated with sterile water. Sections of root containing syncytia have been excised from the thin and transparent roots of Arabidopsis and collected into RNAlater solution (Ambion) at 21 days post infection (Growth Stage 6.1 Boyes et al. 2001). The female nematode has been removed with watch-maker's forceps. Equivalent sections of root have been harvested from non-infected plants. Material has been collected from c. 1000 plants for each of the two samples and the uninfected material serves as an internal control. Total RNA has been prepared from the reference and test root material using an RNeasy plant RNA preparation kit (Qiagen) according to methods required by GARNET.
2022-11-21 | E-NASC-3 | biostudies-arrayexpress
Project description:Aim: To determine the effect of an AtrbohC mutation on the gene expression pattern in primary root tissue, to identify candidate genes acting downstream of AtrbohC, particularly any encoding antioxidant-related proteins, signal transduction components or proteins known to be required for normal root-hair development. Background: Root-hairs are a model system for investigating plant cell polarity. The root-hair mutant rhd2 (Schiefelbein and Somerville, 1990. Plant Cell, 2:235) has short hairs that burst at their tips, (Jones and Smirnoff, unpublished). RHD2 has been cloned and is identical to AtrbohC (L. Dolan, pers. comm.), which encodes a homologue of the superoxide-generating neutrophil respiratory burst oxidase catalytic subunit gp91phox (Torres et al., 1998. Plant J., 14:365). Superoxide rapidly dismutates to hydrogen peroxide (H2O2), suggesting that the rhd2 phenotype may result from reduced H2O2 levels in root-hair cells. Low doses of exogenous antioxidants phenocopy the rhd2 root-hair phenotype in wild-type plants (Jones and Smirnoff, unpublished) further supporting a role for H2O2 in root-hair growth. Fluorescent dyes that detect H2O2 show distinct localisation patterns in growing root-hair cells, (Jones and Smirnoff, unpublished). H2O2 may be an important second messenger in plant cell signalling with proposed roles in the development of cotton fibres (Potikha et al., 1999. Plant Physiol., 119: 849) and in ABA-induced stomatal closure (Zhang et al., 2001. Plant Physiol., 126: 1438). In cultured Arabidopsis cells H2O2 induces gene expression, including that of a gp91phox homologue, (Desikan et al., 1998. J. Exp. Bot., 49: 1767; Desikan, et al., 2000. Free Rad. Biol. Med., 28: 773; Baxter-Burrell et al., 2002. Science, 296: 2026) and activates a MAP kinase cascade (Desikan et al., 1999. J. Exp Bot., 50: 1863). cDNA microarray technology has been used previously to examine the effects of H2O2 on gene expression during oxidative stress (Desikan et al., 2001. Plant Physiol., 127: 159). We wish to investigate the effects of H2O2 on gene expression during root development using the rhd2 mutant. We are currently determining the expression pattern of RHD2. By extracting RNA from the small region of the primary root (for wild-type and rhd2 plants grown in sterile conditions) where root hairs are growing we hope to enrich for root-hair RNAs. This may reveal candidate genes that could be examined more closely at the single-cell level. This approach will provide new insights into the role of H2O2 in root-hair development.
2022-11-21 | E-NASC-54 | biostudies-arrayexpress
Project description:Root architecture is vital for plant growth and largely depends on primary root growth and lateral root development. Several plant hormones have been shown to affect root architecture among which auxin has been granted a central role. Lately, small signalling peptides also emerged as potential molecular components regulating root growth and development. Here, we identified C-TERMINALLY ENCODED PEPTIDE 5 (CEP5) as a novel, phloem poleexpressed paracrine signal for lateral root initiation. Our genetic, biochemical and pharmacological results show that CEP5 counteracts auxin signalling by stabilizing AUXIN/INDOLE ACETIC ACID (AUX/IAA) transcriptional repressors, suggesting the existence of an additional control mechanism through which plants can attenuate auxin signalling in a developmental context. Reducing CEP5 expression levels resulted in an increased auxin response and subsequently interfered with the normal progression through lateral root developmental stages.
2022-03-01 | PXD002589 | Pride
Project description:Aim: To determine the effect of an AtrbohC mutation on the gene expression pattern in primary root tissue, to identify candidate genes acting downstream of AtrbohC, particularly any encoding antioxidant-related proteins, signal transduction components or proteins known to be required for normal root-hair development. Background: Root-hairs are a model system for investigating plant cell polarity. The root-hair mutant rhd2 (Schiefelbein and Somerville, 1990. Plant Cell, 2:235) has short hairs that burst at their tips, (Jones and Smirnoff, unpublished). RHD2 has been cloned and is identical to AtrbohC (L. Dolan, pers. comm.), which encodes a homologue of the superoxide-generating neutrophil respiratory burst oxidase catalytic subunit gp91phox (Torres et al., 1998. Plant J., 14:365). Superoxide rapidly dismutates to hydrogen peroxide (H2O2), suggesting that the rhd2 phenotype may result from reduced H2O2 levels in root-hair cells. Low doses of exogenous antioxidants phenocopy the rhd2 root-hair phenotype in wild-type plants (Jones and Smirnoff, unpublished) further supporting a role for H2O2 in root-hair growth. Fluorescent dyes that detect H2O2 show distinct localisation patterns in growing root-hair cells, (Jones and Smirnoff, unpublished). H2O2 may be an important second messenger in plant cell signalling with proposed roles in the development of cotton fibres (Potikha et al., 1999. Plant Physiol., 119: 849) and in ABA-induced stomatal closure (Zhang et al., 2001. Plant Physiol., 126: 1438). In cultured Arabidopsis cells H2O2 induces gene expression, including that of a gp91phox homologue, (Desikan et al., 1998. J. Exp. Bot., 49: 1767; Desikan, et al., 2000. Free Rad. Biol. Med., 28: 773; Baxter-Burrell et al., 2002. Science, 296: 2026) and activates a MAP kinase cascade (Desikan et al., 1999. J. Exp Bot., 50: 1863). cDNA microarray technology has been used previously to examine the effects of H2O2 on gene expression during oxidative stress (Desikan et al., 2001. Plant Physiol., 127: 159). We wish to investigate the effects of H2O2 on gene expression during root development using the rhd2 mutant. We are currently determining the expression pattern of RHD2. By extracting RNA from the small region of the primary root (for wild-type and rhd2 plants grown in sterile conditions) where root hairs are growing we hope to enrich for root-hair RNAs. This may reveal candidate genes that could be examined more closely at the single-cell level. This approach will provide new insights into the role of H2O2 in root-hair development. Experiment Overall Design: Number of plants pooled:100
2008-06-14 | E-GEOD-6165 | biostudies-arrayexpress
Project description:The acquisition of water and nutrients by plant roots is a fundamental aspect of agriculture and strongly depends on root architecture. Root branching and expansion of the root system is achieved through the development of lateral roots and is to a large extent controlled by the plant hormone auxin. However, the pleiotropic effects of auxin or auxin-like molecules on root systems complicate the study of lateral root development. Here we describe a small-molecule screen in Arabidopsis thaliana that identified naxillin as what is to our knowledge the first non-auxin-like molecule that promotes root branching. By using naxillin as a chemical tool, we identified a new function for root cap-specific conversion of the auxin precursor indole-3-butyric acid into the active auxin indole-3-acetic acid and uncovered the involvement of the root cap in root branching. Delivery of an auxin precursor in peripheral tissues such as the root cap might represent an important mechanism shaping root architecture. To further explore the specificity of naxillin for lateral root development, we compared the early effects of naxillin at the transcriptome level with NAA (1-Naphthaleneacetic acid) in roots of 3-day-old seedlings after 2-h and 6-h treatment. Arabidopsis thaliana (L). Heynh., Col-0 seeds were germinated vertically on solid medium derived from standard MS medium supplemented with 10 μM NPA (1-N-Naphthylphthalamic acid). Three days after germination, plants were transferred to 10 μM NAA (1-Naphthaleneacetic acid) or 50 μM naxillin for 2 and 6 hours. Plants were sampled before (Roots at T0, NPA) or after treatment (Roots at T1 and T2). RNA isolation was performed on 500 root sections (only root without meristems) for each sample. All sampling points were performed in three independent experiments.
2012-12-18 | E-GEOD-42896 | biostudies-arrayexpress