In this study, we used a cross-species network approach to uncover nitrogen (N)-regulated network modules conserved across a model and a crop species. By translating gene network knowledge from the data-rich model Arabidopsis (Arabidopsis thaliana, ecotype Columbia-0) to a crop, rice (Oryza sativa spp. japonica (Nipponbare)), we identified evolutionarily conserved N-regulatory modules as targets for translational studies to improve N use efficiency in transgenic plants.
Cross-Species Network Analysis Uncovers Conserved Nitrogen-Regulated Network Modules in Rice.
Age, Specimen part
View SamplesThe organs of multicellular species are comprised of cell types that must function together to perform specific tasks. One critical organ function is responding to internal or external change but little is known about how responses are tailored to specific cell types or coordinated among them on a global level. Here we use cellular profiling of five Arabidopsis root cell types in response to a limiting resource, nitrogen, to uncover a vast and predominantly cell-specific response that was largely undetectable using traditional methods. These methods reveal a new class of cell-specific nitrogen responses. As a proof-of-principle, we dissected one cell-specific response circuit that mediates nitrogen-induced changes in root branching from pericycle cells. Thus, cellular response profiling links gene modules to discrete functions in specific cell types.
Cell-specific nitrogen responses mediate developmental plasticity.
Specimen part
View SamplesThis work uses a time series in order to decipher gene relationships and consequently to build core regulatory networks involved in Arabidopsis root adaptation to NO3- provision. The experimental approach has been to monitor genome response to NO3- at 3, 6, 9, 12, 15 and 20 min, using ATH1 chips. This high-resolution time course analysis demonstrated that the previously known primary nitrate response is actually preceded by very fast (within 3 min) gene expression modulation, involving genes/functions needed to prepare plants to use/reduce NO3-. State-space modeling (a machine learning approach) has been used to successfully predict gene behavior in unlearnt conditions.
Predictive network modeling of the high-resolution dynamic plant transcriptome in response to nitrate.
Specimen part, Treatment
View SamplesNitrogen and light are two major regulators of plant metabolism and development. While genes involved in the control of each of these signals have begun to be identified, regulators that integrate gene responses to nitrogen and light signals have yet to be determined.
Modeling the global effect of the basic-leucine zipper transcription factor 1 (bZIP1) on nitrogen and light regulation in Arabidopsis.
Specimen part
View SamplesWe investigated the morphological roots decisions of Arabidopsis in a NO3- heterogeneous medium. To do so, we used the Split-Root System which is an experimental set up to assess root decisions in nutrient heterogeneous medium. Split-root plants have been subjected to three different treatments. Control KNO3 plants received KNO3 on both sides of the root system (C.NO3) and Control KCl plants received KCl on both sides (C.KCl) as a nitrogen deprivation treatment. 'Split' plants received KNO3 on one side (Sp.NO3) and KCl on the other side (Sp.KCl) of the root system to assess the root decision-making in a heterogeneous environment.
Nitrogen economics of root foraging: transitive closure of the nitrate-cytokinin relay and distinct systemic signaling for N supply vs. demand.
Specimen part, Treatment
View SamplesBACKGROUND:Dynamic transcriptional regulation is critical for an organism's response to environmental signals and yet remains elusive to capture. Such transcriptional regulation is mediated by master transcription factors (TF) that control large gene regulatory networks. Recently, we described a dynamic mode of TF regulation named "hit-and-run". This model proposes that master TF can interact transiently with a set of targets, but the transcription of these transient targets continues after the TF dissociation from the target promoter. However, experimental evidence validating active transcription of the transient TF-targets is still lacking.
"Hit-and-Run" transcription: de novo transcription initiated by a transient bZIP1 "hit" persists after the "run".
Specimen part
View SamplesThis microarray experiment serves to identify the genes in the Arabidopsis genome that are regulated by carbon and light signaling interactions in 7 day dark grown seedlings. The expression profile of wild-type will be compared to the cli186 mutant, a mutant defective in carbon and light signaling. Plants of both the wild-type and cli186 genotypes are treated with the following light (L) and carbon (C) treatments: -C-L, +C-L, +C+L, -C+L. Comparison of the expression profiles under all treatments will help to identify genes that are misregulated in carbon and/or light treatments in the cli186 mutant.
An integrated genetic, genomic and systems approach defines gene networks regulated by the interaction of light and carbon signaling pathways in Arabidopsis.
Age
View SamplesHistone methylation modulates gene expression in response to external and internal cues. We uncovered a non-redundant role for the Arabidopsis histone methyltransferase, SDG8, which provides a unique opportunity to study the global function of a specific histone methyltransferase within in a multicellular organism. We previously used a promoter responsive to light and carbon in a positive genetic screen to identify an Arabidopsis carbon and light insensitive mutant cli186. In this study, we characterize the mutant cli186 as a complete deletion of a histone methyltransferase gene SDG8 (now renamed sdg8-5). To assess the global role of SDG8, we compared the global histone methylation patterns and the transcriptome of sdg8-5 to wild type (WT) in the context of a transient carbon and light treatment. We showed that the complete deletion of SDG8 in sdg8-5 is associated with a dramatic reduction of H3K36me3 towards the 3 of the gene body, which correlates with significant reduction in gene expression. We uncovered 1,084 high confidence functional targets of SDG8 affected in both H3K36me3 marks and gene expression that are associated with specific biological processes including defense, photosynthesis, nutrient metabolism and energy metabolism. Importantly, 71% of these functional targets are responsive to carbon and/or light. Our model suggests that SDG8 functions to mark specific sets of genes with H3K36me3 in the gene body for active transcription, to tune genes involved in primary metabolism that are responsive to the energy level in the environment.
The histone methyltransferase SDG8 mediates the epigenetic modification of light and carbon responsive genes in plants.
Treatment
View SamplesThis work studies the impact of AtNIGT1/HRS1-GR entrance in the nucleus upon DEX treatment in protoplasts.
AtNIGT1/HRS1 integrates nitrate and phosphate signals at the Arabidopsis root tip.
No sample metadata fields
View SamplesLiving organisms have to cope with multiple and combined fluctuations in their environment. According to their sessile mode of life, plants are even more subjected to such fluctuations impacting their physiology and development. In particular, nutrient availability is known to tune plant development through modulating hormonal signaling, and conversely, hormonal signals are key to control nutrient related signaling pathways (Krouk et al., 2011a). However, very few is known about molecular mechanisms leading to plant adaptation to such combined signals. Here we deployed an unprecedented combinatorial treatment matrix to reveal plant adaptation in response to nitrate (NO3-), ammonium (NH4+), auxin (IAA), cytokinins (CK) and abscisic acid (ABA) and their exhaustive binary combinations.
Combinatorial interaction network of transcriptomic and phenotypic responses to nitrogen and hormones in the Arabidopsis thaliana root.
Specimen part, Time
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