Arabidopsis thaliana
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA369102 | ENA |
REPOSITORIES: ENA
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Project description:Plants uptake nitrogen (N) from the soil mainly in the form of nitrate. However, nitrate is often distributed heterogeneously in natural soil. Plants, therefore, have a systemic long-distance signaling mechanism by which N-starvation on one side of the root leads to a compensatory N uptake on the other N-rich side. This systemic N acquisition response is triggered by a root-to-shoot mobile peptide hormone, C-terminally Encoded Peptide (CEP), originating from the N-starved roots, but the molecular nature of the descending shoot-to-root signal remains elusive. Here, we show that phloem-specific polypeptides that are induced in leaves upon perception of root-derived CEP act as descending long-distance mobile signals translocated to each root. These shoot-derived polypeptides, which we named CEP Downstream 1 (CEPD1) and CEPD2, upregulate the expression of the nitrate transporter gene NRT2.1 in roots specifically when nitrate is present in the rhizosphere. Arabidopsis plants deficient in this pathway show impaired systemic N-acquisition response accompanied with N-deficiency symptoms. These fundamental mechanistic insights should provide a conceptual framework for understanding systemic nutrient acquisition responses in plants. We prepared total RNA from vascular tissues of wild type, CEP1-treated wild type, and cepr1-1 mutant, and used a microarray analysis to identify genes specifically induced by CEP1.
2017-04-06 | GSE94161 | GEO
Project description:Plants modulate the efficiency of root nitrogen (N) acquisition in response to shoot N demand. However, molecular components directly involved in this shoot-to-root communication remain to be identified. Here, we show that phloem-mobile CEPD-like 2 (CEPDL2) polypeptide is upregulated in the leaf vasculature in response to decreased shoot N status and, after translocation to the roots, promotes high-affinity uptake and root-to-shoot transport of nitrate by activating nitrate transporter genes such as NRT2.1, NRT3.1 and NRT1.5. Loss of CEPDL2 decreases nitrate uptake and root-to-shoot transport activity in roots, leading to a reduction in shoot nitrate content and plant biomass. CEPDL2 contributes to N acquisition cooperatively with CEPD1 and CEPD2 that mediate root N status, and their complete loss severely impairs N homeostasis in plants. Reciprocal grafting analysis provided conclusive evidence that the shoot CEPDL2/CEPD genotype defines the root high-affinity uptake activity of nitrate. Our results indicate that plants integrate shoot N status and root N status in leaves and systemically regulate the efficiency of root N acquisition.
2020-02-10 | GSE140834 | GEO
Project description:Plants face temporal and spatial variation in nitrogen (N) availability. This includes heterogeneity in soil nitrate (NO3-) content. To face these constraints, plants modify their gene expression and physiological processes to optimize N acquisition. This plasticity relies on a complex long-distance root-shoot-root signaling network that remains poorly understood. We previously showed that cytokinin (CK) biosynthesis is required to trigger systemic N signaling. Here, we performed split-root experiments and used a combination of CK-related mutant analyses, hormone profiling, transcriptomic analysis, NO3- uptake assays, and root growth measurements to gain insight into systemic N signaling in Arabidopsis thaliana. By comparing wild-type plants and mutants affected in CK biosynthesis and ABCG14-dependent root-to-shoot translocation of CK, we revealed an important role for active trans-Zeatin (tZ) in systemic N signaling. Both rapid sentinel gene regulation and long-term functional acclimation to heterogeneous NO3- supply, including NO3- transport and root growth regulation, are likely mediated by the integration of tZ content in shoots. Furthermore, shoot transcriptome profiling revealed that glutamate/glutamine metabolism is likely a target of tZ root-to-shoot translocation, prompting an interesting hypothesis regarding shoot-to-root communication. Finally, this study highlights tZ-independent pathways regulating gene expression in shoots as well as NO3- uptake activity in response to total N-deprivation. We used microarrays to detail transcriptional reprogramming occurring in shoots in response to heterogeneous nitrate supply compared to homogeneous nitrate supply in wild-type Arabidopsis thaliana plants and in two mutants affected in cytokinin biosynthesis and transport.
2018-05-09 | GSE114162 | GEO
Project description:RNA silencing is a mechanism for regulating gene expression at the transcriptional and post-transcriptional levels. Its functions include regulating endogenous gene expression and protecting the cell against viruses and invading transposable elements (TEs). A key component of the mechanism is small RNAs (sRNAs) of 21-24 nucleotides (nt) in length, which direct the silencing machinery in a sequence specific manner to target nucleic acids. sRNAs of 24 nt are involved in methylation of cytosine residues of target loci in three sequence contexts (CG, CHG and CHH), referred to as RNA-directed DNA methylation (RdDM). We previously demonstrated that 24 nt sRNAs are mobile from shoot to root in Arabidopsis thaliana. In this study we demonstrated that methylation of thousands of loci in root tissues is dependent upon mobile sRNAs from the shoot. Furthermore, we found that mobile sRNA-dependent DNA methylation occurs predominantly in non-CG contexts. These findings were made using base-resolution next generation sequencing approaches and genome wide analyses. Specific classes of short TEs are the predominant targets of mobile sRNA-dependent DNA methylation; classes typically found in gene-rich euchromatic regions. Mobile sRNA-regulated genes were also identified. Mechanistically, we demonstrate that mobile sRNA-dependent non-CG methylation is largely independent of the CMT2/3 RdDM pathway but dependent upon the DRM1/DRM2 RdDM pathway. This is in contrast to non-mobile sRNA-dependent DNA methylation, which predominantly depends upon the CMT2/3 RdDM pathway. These data are complementary to the small RNA sequencing data from Arabidopsis root grafts described in Molnar et al (Science, 2010 May 14;328(5980):872-5).
2016-01-04 | E-MTAB-3473 | biostudies-arrayexpress
Project description:Unlike plants in the field, which experience significant temporal fluctuations in environmental conditions, plants in the laboratory are typically grown in controlled, stable environments. Therefore, signaling pathways evolved for survival in continuously fluctuating environments often remain functionally latent in laboratory settings. Here, we show that TGA1 and TGA4 act as hub transcription factors through which the expression of genes involved in high-affinity nitrate uptake are regulated in response to shoot-derived phloem mobile polypeptides, CEP DOWNSTREAM 1 (CEPD1), CEPD2 and CEPD-like 2 (CEPDL2) as nitrogen (N) deficiency signals, and Glutaredoxin S1 (GrxS1) to GrxS8 as N sufficiency signals. CEPD1/2/CEPDL2 and GrxS1-S8 competitively bind to TGA1/4 in roots, with the former acting as transcription coactivators that enhance the uptake of nitrate, while the latter function as corepressor complexes together with TOPLESS (TPL), TPL-related 1 (TPR1) and TPR4 to limit nitrate uptake. Arabidopsis plants deficient in TGA1/4 maintain basal nitrate uptake and exhibit growth similar to wild-type plants in a stable N environment, but were impaired in regulation of nitrate acquisition in response to shoot N demand, leading to defective growth under continuously fluctuating N environments where rhizosphere nitrate ions switch periodically between deficient and sufficient states. TGA1/4 are crucial transcription factors that enable plants to survive under fluctuating and challenging N environmental conditions.
2024-07-11 | GSE240737 | GEO
Project description:Unlike plants in the field, which experience significant temporal fluctuations in environmental conditions, plants in the laboratory are typically grown in controlled, stable environments. Therefore, signaling pathways evolved for survival in continuously fluctuating environments often remain functionally latent in laboratory settings. Here, we show that TGA1 and TGA4 act as hub transcription factors through which the expression of genes involved in high-affinity nitrate uptake are regulated in response to shoot-derived phloem mobile polypeptides, CEP DOWNSTREAM 1 (CEPD1), CEPD2 and CEPD-like 2 (CEPDL2) as nitrogen (N) deficiency signals, and Glutaredoxin S1 (GrxS1) to GrxS8 as N sufficiency signals. CEPD1/2/CEPDL2 and GrxS1-S8 competitively bind to TGA1/4 in roots, with the former acting as transcription coactivators that enhance the uptake of nitrate, while the latter function as corepressor complexes together with TOPLESS (TPL), TPL-related 1 (TPR1) and TPR4 to limit nitrate uptake. Arabidopsis plants deficient in TGA1/4 maintain basal nitrate uptake and exhibit growth similar to wild-type plants in a stable N environment, but were impaired in regulation of nitrate acquisition in response to shoot N demand, leading to defective growth under continuously fluctuating N environments where rhizosphere nitrate ions switch periodically between deficient and sufficient states. TGA1/4 are crucial transcription factors that enable plants to survive under fluctuating and challenging N environmental conditions.
2024-07-11 | GSE240736 | GEO
Project description:In plants, nitrate is suggested to act as an indicator of nitrogen (N) status that modulates N responses under steady-state conditions. Our preceding study suggested that shoot nitrate accumulation alone represses expression of N starvation-inducible genes in shoots and roots. Notably, we observed that shoot nitrate accumulation was accompanied by increases in shoot expression of ISOPENTENYL TRANSFERASE 3 (IPT3) and shoot levels of N6-(Δ2-isopentenyl) adenine (iP)-type CK. IPT3 expression is localized primarily in phloem companion cells, and iP-type CKs, which are synthesized by IPT3, are phloem-mobile. Hence, both local and systemic responses to shoot nitrate status may be regulated by IPT3-synthesized iP-type CKs. Thus, the present study aims to dissect the local/systemic responses to shoot nitrate status and their dependence on shoot IPT3. To achieve this, we developed a novel experimental system to manipulate nitrate levels and IPT3 expression in a shoot-specific manner using grafted plants derived from the plants lacking nitrate reductase and/or IPT3. Using shoots and roots from the grafted plants, RNA-seq analysis was performed.
2024-08-31 | E-MTAB-14302 | biostudies-arrayexpress
Project description:Injured plant somatic tissues regenerate themselves by establishing the shoot or root meristems. In Arabidopsis (Arabidopsis thaliana) a two-step culture system ensures regeneration by first promoting the acquisition of pluripotency and subsequently specifying the fate of new meristems. Although previous studies have reported the importance of phytohormones auxin and cytokinin in determining the fate of new meristems, it remains elusive whether and how the environmental factors influence this process. In this study, we investigated the impact of light signals on shoot regeneration using Arabidopsis hypocotyl as explants. We found that light signals promote shoot regeneration while inhibiting root formation. ELONGATED HYPOCOTYL 5 (HY5), the pivotal transcriptional factor in light signaling, plays a central role in this process by mediating the expression of key genes controlling the fate of new meristems. Specifically, HY5 directly represses root development genes and activates shoot meristem genes, leading to the establishment of shoot progenitor from pluripotent callus. We further demonstrated that the early activation of photosynthesis is critical for shoot initiation, and this is transcriptionally regulated downstream of the HY5-dependent pathways. In conclusion, we uncovered the intricate molecular mechanisms by which light signals control the establishment of new meristem through the regulatory network governed by HY5, thus, highlighting the influence of light signals on plant developmental plasticity.
2024-09-16 | GSE236147 | GEO
Project description:Waters Raw data can be downloaded for shoot- and root parts of Arabidopsis thaliana accessions.
2018-11-14 | ST001096 | MetabolomicsWorkbench
Project description:De novo shoot organogenesis (DNSO) is a commonly used pathway for plant biotechnology, and is a hormonally regulated process, where auxin and cytokinin coordinates suites of genes encoding transcription factors, general transcription factors, and RNA metabolism machinery genes. Here we report that silencing Arabidopsis thaliana CTD phosphatase-like 4 (CPL4RNAi), which increases phosphorylation level of RNA polymerase II (pol II) CTD, altered lateral root development and DNSO efficiency of the host plants, suggesting an importance of precise control of pol II activities during DNSO. Under standard condition, roots of CPL4RNAi lines produced no or few lateral roots. When induced by high concentration of auxin, CPL4RNAi lines failed to produce focused auxin maxima at the meristem of lateral root primordia, and produced fasciated lateral roots. By contrast, root explants of CPL4RNAi lines were highly competent for DNSO. Efficient DNSO of CPL4RNAi lines were observed even under 10 times less cytokinin required for wild type explants. Transcriptome analysis showed CPL4RNAi but not wild type explants expressed high levels of shoot meristem related genes during priming by high auxin/cytokinin ratio, and subsequent shoot induction with cytokinin. These results indicate that CPL4 functions as a repressor of the early stage of DNSO, during acquisition of competency by high auxin/cytokinin ratio, perhaps via regulation of pol II activities.
2020-09-19 | GSE104083 | GEO