Aluminum (Al) is a major limiting factor for crop production on acidic soils, inhibiting root growth and plant development. At acidic pH (pH < 5.5), Al3+ ions are the main form of Al present in the media. Al3+ ions have an increased... more
Aluminum (Al) is a major limiting factor for crop production on acidic soils, inhibiting root growth and plant development. At acidic pH (pH < 5.5), Al3+ ions are the main form of Al present in the media. Al3+ ions have an increased solubility at pH < 5.5 and result in plant toxicity. At higher pH, the free Al3+ fraction decreases in the media, but whether plants can detect Al at these pHs remain unknown. To cope with Al stress, the SENSITIVE TO PROTON RHIZOTOXICITY1 (STOP1) transcription factor induces AL-ACTIVATED MALATE TRANSPORTER1 (ALMT1), a malate-exuding transporter as a strategy to chelate the toxic ions in the rhizosphere. Here, we uncoupled the Al signalling pathway that controls STOP1 from Al toxicity using wild type (WT) and two stop1 mutants carrying the pALMT1:GUS construct with an agar powder naturally containing low amounts of phosphate, iron (Fe), and Al. We combined gene expression [real-time PCR (RT-PCR) and the pALMT1:GUS reporter], confocal microscopy (pST...
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Figure 4-source data 3: Average methylation levels observed in the roots of the progeny of stressed- and non-stressed plants in all contexts and methylation levels for each replicate in CNN in the 175 root PSI DMRs
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Figure 4-source data 1: List of 14 root persisting PSI DMRs, despite 31 d of Pi resupply
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Figure 2-source data 1: List of 175 PSI DMRs identified in the root, with DNA methylation levels and transcription levels of DMR-associated genes
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Figure 5-source data 2: 11 DCL3a-dependant PSI DMRs, with methylation levels and associated gene transcription
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Cytosine DNA methylation (mC) is a genome modification that can regulate the expression of coding and non-coding genetic elements. However, little is known about the involvement of mC in response to environmental cues. Using whole genome... more
Cytosine DNA methylation (mC) is a genome modification that can regulate the expression of coding and non-coding genetic elements. However, little is known about the involvement of mC in response to environmental cues. Using whole genome bisulfite sequencing to assess the spatio-temporal dynamics of mC in rice grown under phosphate starvation and recovery conditions, we identified widespread phosphate starvation-induced changes in mC, preferentially localized in transposable elements (TEs) close to highly induced genes. These changes in mC occurred after changes in nearby gene transcription, were mostly DCL3a-independent, could partially be propagated through mitosis, however no evidence of meiotic transmission was observed. Similar analyses performed in Arabidopsis revealed a very limited effect of phosphate starvation on mC, suggesting a species-specific mechanism. Overall, this suggests that TEs in proximity to environmentally induced genes are silenced via hypermethylation, and establishes the temporal hierarchy of transcriptional and epigenomic changes in response to stress
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Research Interests: Biology and Arabidopsis
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The chloroplast signal recognition particle (cpSRP) is a protein complex consisting of 54- and 43-kD subunits encoded by the fifty-four chloroplast, which encodes cpSRP54 (ffc), and chaos (cao) loci, respectively. Two new null alleles in... more
The chloroplast signal recognition particle (cpSRP) is a protein complex consisting of 54- and 43-kD subunits encoded by the fifty-four chloroplast, which encodes cpSRP54 (ffc), and chaos (cao) loci, respectively. Two new null alleles in the ffc locus have been identified.ffc1-1 is caused by a stop codon in exon 10, whileffc1-2 has a large DNA insertion in intron 8.ffc mutants have yellow first true leaves that subsequently become green. The reaction center proteins D1, D2, and psaA/B, as well as seven different light-harvesting chlorophyll proteins (LHCPs), were found at reduced levels in the youngffc leaves but at wild-type levels in the older leaves. The abundance of the two types of LHCP was unaffected by the mutation, while two others were increased in the absence of cpSRP54. Null mutants in the cao locus contain reduced levels of the same subset of LHCP proteins as ffc mutants, but are distinguishable in four ways: young leaves are greener, the chlorophylla/b ratio is elevated...
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Chemical genetics has emerged as a powerful approach to dissect biological processes, based on the utilization of small molecules disturbing the function of specific target proteins. By analogy with classical genetics,... more
Chemical genetics has emerged as a powerful approach to dissect biological processes, based on the utilization of small molecules disturbing the function of specific target proteins. By analogy with classical genetics, &amp;amp;amp;amp;#39;reverse chemical genetics&amp;amp;amp;amp;#39; refers to the utilization of drugs acting on a known target, enabling its functional characterization at the levels of the cells, tissues and organisms. Likewise, &amp;amp;amp;amp;#39;direct chemical genetics&amp;amp;amp;amp;#39; refers to the utilization of a drug of unknown mode of action, but triggering a phenotype of interest. In that case, one has to identify the target(s) possibly blocked (or possibly activated) by the small molecule. This chapter illustrates both approaches, like the analysis of the elongation of fatty acids, the biosynthesis of galactoglycerolipids or the catabolism of phosphoglycerolipids by reverse chemical genetics or the study of the membrane glycerolipid remodeling triggered upon phosphate starvation, by direct chemical genetics.
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ABSTRACT
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Marin, E.; Nussaume, L.; Quesada, A.; Gonneau, M.; Sotta, B.; Hugueney, P.; Frey, A.; Marion-Poll, A.: Molecular identification of zeaxanthin epoxidase of Nicotiana plumbaginifolia, a gene involved in abscisic acid biosynthesis and corresponding to the ABA locus of Arabidopsis thaliana. EMBO J., ...more
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The nitrate assimilatory pathway has been the matter of intensive molecular and cellular analysis in solanaceous species. In this report we will present data on the function of the N-terminal part of the enzyme nitrate reductase, on the... more
The nitrate assimilatory pathway has been the matter of intensive molecular and cellular analysis in solanaceous species. In this report we will present data on the function of the N-terminal part of the enzyme nitrate reductase, on the cloning of genes of the molybdenum cofactor biosythesis, and on the characterization of a transcription factor presumed to be involved in the expression of genes of the nitrate assimilatory pathway.
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The signal recognition particle (SRP), a ribonucleoprotein complex that is conserved across all organisms, is essential for cotranslational insertion of proteins into membranes. A three-dimensional structure of cpSRP43 provides insights... more
The signal recognition particle (SRP), a ribonucleoprotein complex that is conserved across all organisms, is essential for cotranslational insertion of proteins into membranes. A three-dimensional structure of cpSRP43 provides insights into how plants have adapted the SRP for post-translational targeting of membrane proteins.
Research Interests: Biochemistry, Bioinformatics, Environmental Science, Developmental Biology, Climate Change, and 15 moreComputational Biology, Biotechnology, Cancer, Biology, Cell Cycle, Ecology, Drug Discovery, Astrophysics, Astronomy, DNA, Cell Signalling, Chloroplast, Earth Science, Biochemistry and cell biology, and Chloroplasts
The early light-induced proteins (ELIPs) belong to the multigenic family of light-harvesting complexes, which bind chlorophyll and absorb solar energy in green plants. ELIPs accumulate transiently in plants exposed to high light... more
The early light-induced proteins (ELIPs) belong to the multigenic family of light-harvesting complexes, which bind chlorophyll and absorb solar energy in green plants. ELIPs accumulate transiently in plants exposed to high light intensities. By using an Arabidopsis thaliana mutant ( chaos ) affected in the posttranslational targeting of light-harvesting complex-type proteins to the thylakoids, we succeeded in suppressing the rapid accumulation of ELIPs during high-light stress, resulting in leaf bleaching and extensive photooxidative damage. Constitutive expression of ELIP genes in chaos before light stress resulted in ELIP accumulation and restored the phototolerance of the plants to the wild-type level. Free chlorophyll, a generator of singlet oxygen in the light, was detected by chlorophyll fluorescence lifetime measurements in chaos leaves before the symptoms of oxidative stress appeared. Our findings indicate that ELIPs fulfill a photoprotective function that could involve eith...
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L’initiation des racines laterales est un determinant majeur de l’architecture de la racine. Ce travail caracterise l’assise cellulaire qui donne naissance aux racines laterales chez les plantes dicotyledonees ; le pericycle. Il est... more
L’initiation des racines laterales est un determinant majeur de l’architecture de la racine. Ce travail caracterise l’assise cellulaire qui donne naissance aux racines laterales chez les plantes dicotyledonees ; le pericycle. Il est souvent considere comme une assise concentrique et homogene. Les resultats obtenus grâce a des marqueurs, un crible genetique et enfin l’etude du transcriptome des cellules etudiees confirment l’idee selon laquelle le pericycle est compose de deux types de cellules differents. Nous proposons ainsi un nouveau modele dans lequel la specification des cellules du pericycle et des tissus vasculaires prend place tres tot au cours du developpement, depend de regulations genetiques communes, mais dans lequel les differentiations peuvent etre, au moins partiellement, dissociees. Ceci modifie la vision classique de l’organisation de ces cellules selon une structure bilaterale, dont l’identite est intimement liee a celle des tissus vasculaires adjacents.
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SummaryBiochemical and genetic studies have established that the light‐harvesting chlorophyll proteins (LHCPs) of the photosystems use the cpSRP (chloroplast signal recognition particle) pathway for their targeting to thylakoids. Previous... more
SummaryBiochemical and genetic studies have established that the light‐harvesting chlorophyll proteins (LHCPs) of the photosystems use the cpSRP (chloroplast signal recognition particle) pathway for their targeting to thylakoids. Previous analyses of single cpSRP mutants, chaos and ffc, deficient in cpSRP43 and cpSRP54, respectively, have revealed that half of the LHCPs are still integrated into the thylakoid membranes. Surprisingly, the effects of both mutations are additive in the double mutant ffc/chaos described here. This mutant has pale yellow leaves at all stages of growth and drastically reduced levels of all the LHCPs except Lhcb 4. Although the chloroplasts have a normal shape, the thylakoid structure is affected by the mutation, probably as a consequence of reduction of all the LHCPs. ELIPs (early light‐inducible proteins), nuclear‐encoded proteins related to the LHCP family and inducible by light stress, were also drastically reduced in the double mutant. However, protei...
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SummaryThe early light‐induced proteins (ELIPs) belong to the multigenic family of pigment‐binding light‐harvesting complexes. ELIPs accumulate transiently and are believed to play a protective role in plants exposed to high levels of... more
SummaryThe early light‐induced proteins (ELIPs) belong to the multigenic family of pigment‐binding light‐harvesting complexes. ELIPs accumulate transiently and are believed to play a protective role in plants exposed to high levels of light. Constitutive expression of the ELIP2 gene in Arabidopsis resulted in a marked reduction of the pigment content of the chloroplasts, both in mature leaves and during greening of etiolated seedlings. The chlorophyll loss was associated with a decrease in the number of photosystems in the thylakoid membranes, but the photosystems present were fully assembled and functional. A detailed analysis of the chlorophyll‐synthesizing pathway indicated that ELIP2 accumulation downregulated the level and activity of two important regulatory steps: 5‐aminolevulinate synthesis and Mg‐protoporphyrin IX (Mg‐Proto IX) chelatase activity. The contents of glutamyl tRNA reductase and Mg chelatase subunits CHLH and CHLI were lowered in response to ELIP2 accumulation. ...
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Förster resonance energy transfer (FRET) measurements based on fluorescence lifetime imaging microscopy (FLIM) are increasingly being used to assess molecular conformations and associations in living systems. Reduction in the... more
Förster resonance energy transfer (FRET) measurements based on fluorescence lifetime imaging microscopy (FLIM) are increasingly being used to assess molecular conformations and associations in living systems. Reduction in the excited-state lifetime of the donor fluorophore in the presence of an appropriately positioned acceptor is taken as strong evidence of FRET. Traditionally, cyan fluorescent protein has been widely used as a donor fluorophore in FRET experiments. However, given its photolabile nature, low quantum yield, and multiexponential lifetime, cyan fluorescent protein is far from an ideal donor in FRET imaging. Here, we report the application and use of the TSapphire mutant of green fluorescent protein as an efficient donor to mOrange in FLIM-based FRET imaging in intact plant cells. Using time-correlated single photon counting-FLIM, we show that TSapphire expressed in living plant cells decays with lifetime of 2.93 ± 0.09 ns. Chimerically linked TSapphire and mOrange (w...
Research Interests: Genetics, Biophysics, Chemistry, Fluorescence, Fluorescence Microscopy, and 15 moreBiology, Cell Biology, Gene expression, Fluorescence Resonance Energy Transfer, Biological Sciences, Fluorophore, Forster Resonance Energy Transfer, Fluorescence Imaging, Green Fluorescent Protein, Excited states, Fluorescent Protein, Energy Transfer, Cell Wall, Autofluorescence, and Breakthrough technologies
Ionic nutrition is essential for plant development. Many techniques have been developed to image and (or) measure ionic movement in plants. Nevertheless, most of them are destructive and limit the analysis. Here, we present the... more
Ionic nutrition is essential for plant development. Many techniques have been developed to image and (or) measure ionic movement in plants. Nevertheless, most of them are destructive and limit the analysis. Here, we present the development of radioisotope imaging techniques that overcome such restrictions and allow for real-time imaging of ionic movement. The first system, called macroimaging, was developed to visualize and measure ion uptake and translocation between organs at a whole-plant scale. Such a device is fully compatible with illumination of the sample. We also modified fluorescent microscopes to set up various solutions for ion uptake analysis at the microscopic level. Both systems allow numerical analysis of images and possess a wide dynamic range of detection because they are based on radioactivity.
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The peroxide resistant mutant (PR) of Proteus mirabilis was characterized by an increased constitutive catalase activity concomitant with a large production of specific mRNA. Survival toward hydrogen peroxide during exponential phase was... more
The peroxide resistant mutant (PR) of Proteus mirabilis was characterized by an increased constitutive catalase activity concomitant with a large production of specific mRNA. Survival toward hydrogen peroxide during exponential phase was increased by H2O2 pretreatment in the wild type but not in the mutant, although the catalase of both strains was not inducible under these conditions. In the mutant, besides catalase, over-produced proteins comprised two different alkyl hydroperoxide reductase subunit C (AhpC) proteins and a protein homologous to the stationary phase transcription factor SspA of Escherichia coli. Conversely, the flagellin A (FlaA) of P. mirabilis was repressed in the PR mutant. Genomic DNA fragments of 2.9 kb carrying the catalase gene (katA) together with the 5' and 3' flanking regions were isolated from both strains and found to be identical. Upstream of katA, a Fur box-like sequence was found, but surprisingly, restricting iron in the culture medium cause...
Research Interests: Microbiology, Medical Microbiology, Biology, Medicine, Canadian, and 15 moreMutation, Escherichia coli, Catalase, Iron, Hydrogen Peroxide, Peroxidases, Veterinary Sciences, Amino Acid Sequence, Base Sequence, Culture Media, Oxidants, Proteus Mirabilis, Flagellin, Peroxiredoxins, and Molecular Sequence Data
AtHMA4 is an Arabidopsis thaliana P1B‐ATPase which transports Zn and Cd. Here, we demonstrate that AtHMA4 is localized at the plasma membrane and expressed in tissues surrounding the root vascular vessels. The ectopic overexpression of... more
AtHMA4 is an Arabidopsis thaliana P1B‐ATPase which transports Zn and Cd. Here, we demonstrate that AtHMA4 is localized at the plasma membrane and expressed in tissues surrounding the root vascular vessels. The ectopic overexpression of AtHMA4 improved the root growth in the presence of toxic concentrations of Zn, Cd and Co. A null mutant exhibited a lower translocation of Zn and Cd from the roots to shoot. In contrast, the AtHMA4 overexpressing lines displayed an increase in the zinc and cadmium shoot content. Altogether, these results strongly indicate that AtHMA4 plays a role in metal loading in the xylem.
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Research Interests: Homeostasis and Phosphate
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Aluminum (Al) toxicity and inorganic phosphate (Pi) limitation are widespread chronic abiotic and mutually enhancing stresses that profoundly affect crop yield. Both stresses strongly inhibit root growth, resulting from a progressive... more
Aluminum (Al) toxicity and inorganic phosphate (Pi) limitation are widespread chronic abiotic and mutually enhancing stresses that profoundly affect crop yield. Both stresses strongly inhibit root growth, resulting from a progressive exhaustion of the stem cell niche. Here, we report on a casein kinase 2 (CK2) inhibitor identified by its capability to maintain a functional root stem cell niche in Arabidopsis thaliana under Al toxic conditions. CK2 operates through phosphorylation of the cell cycle checkpoint activator SUPPRESSOR OF GAMMA RADIATION1 (SOG1), priming its activity under DNA-damaging conditions. In addition to yielding Al tolerance, CK2 and SOG1 inactivation prevents meristem exhaustion under Pi starvation, revealing the existence of a low Pi-induced cell cycle checkpoint that depends on the DNA damage activator ATAXIA-TELANGIECTASIA MUTATED (ATM). Overall, our data reveal an important physiological role for the plant DNA damage response pathway under agriculturally limi...
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Aluminum (Al) toxicity and inorganic phosphate (Pi) limitation are widespread chronic abiotic and mutually enhancing stresses that profoundly affect crop yield. Both stresses cause a strong inhibition of root growth, resulting from a... more
Aluminum (Al) toxicity and inorganic phosphate (Pi) limitation are widespread chronic abiotic and mutually enhancing stresses that profoundly affect crop yield. Both stresses cause a strong inhibition of root growth, resulting from a progressive exhaustion of the stem cell niche. Here, we report on a casein kinase 2 (CK2) inhibitor identified by its capability to maintain a functional root stem cell niche under Al toxic conditions. CK2 operates through phosphorylation of the cell cycle checkpoint activator SUPPRESSOR OF GAMMA RADIATION1 (SOG1), priming its activity under DNA-damaging conditions. In addition to yielding Al tolerance, CK2 and SOG1 inactivation prevents meristem exhaustion under Pi starvation, revealing the existence of a low Pi-induced cell cycle checkpoint that depends on the DNA damage activator ATAXIA-TELANGIECTASIA MUTATED. Overall, our data reveal an important physiological role for the plant DNA damage response pathway under agriculturally limiting growth condit...
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Research Interests: Biochemistry, Plant Biology, Biology, Medicine, Arabidopsis thaliana, and 4 morePlant, Root growth, Uracil, and cytosine
SummaryLow‐phosphate (Pi) conditions are known to repress primary root growth of Arabidopsis at low pH and in an Fe‐dependent manner. This growth arrest requires accumulation of the transcription factor STOP1 in the nucleus, where it... more
SummaryLow‐phosphate (Pi) conditions are known to repress primary root growth of Arabidopsis at low pH and in an Fe‐dependent manner. This growth arrest requires accumulation of the transcription factor STOP1 in the nucleus, where it activates the transcription of the malate transporter gene ALMT1; exuded malate is suspected to interact with extracellular Fe to inhibit root growth. In addition, ALS3 – an ABC‐like transporter identified for its role in tolerance to toxic Al – represses nuclear accumulation of STOP1 and the expression of ALMT1. Until now it was unclear whether Pi deficiency itself or Fe activates the accumulation of STOP1 in the nucleus. Here, by using different growth media to dissociate the effects of Fe from Pi deficiency itself, we demonstrate that Fe is sufficient to trigger the accumulation of STOP1 in the nucleus, which, in turn, activates the expression of ALMT1. We also show that a low pH is necessary to stimulate the Fe‐dependent accumulation of nuclear STOP...
Research Interests: Plant Biology, Biology, Cell Biology, Medicine, Aluminum, and 10 moreALS, Plant, Iron, Arabidopsis, Transcription Factor, Phosphate, Stop, Nucleus, Extracellular, and root hair
BackgroundRoot architecture varies widely between species and even between ecotypes of the same species despite the strong conservation of the protein-coding portion of their genomes. In contrast, non-coding RNAs evolved rapidly between... more
BackgroundRoot architecture varies widely between species and even between ecotypes of the same species despite the strong conservation of the protein-coding portion of their genomes. In contrast, non-coding RNAs evolved rapidly between ecotypes and may control their differential responses to the environment as several long non-coding RNAs (lncRNAs) can quantitatively regulate gene expression.ResultsRoots from Columbia (Col) and Landsbergerecta(Ler) ecotypes respond differently to phosphate starvation. We compared complete transcriptomes (mRNAs, lncRNAs and small RNAs) of root tips from these two ecotypes during early phosphate starvation. We identified thousands of new lncRNAs categorized as intergenic or antisense RNAs that were largely conserved at DNA level in these ecotypes. In contrast to coding genes, many lncRNAs were specifically transcribed in one ecotype and/or differentially expressed between ecotypes independently of the phosphate condition. These ecotype-related lncRNA...
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Phosphate starvation-mediated induction of the HAD-type phosphatases PPsPase1 (AT1G73010) and PECP1 (AT1G17710) has been reported in Arabidopsis. However, little is known about their in vivo function or impact on plant responses to... more
Phosphate starvation-mediated induction of the HAD-type phosphatases PPsPase1 (AT1G73010) and PECP1 (AT1G17710) has been reported in Arabidopsis. However, little is known about their in vivo function or impact on plant responses to nutrient deficiency. The preferences of PPsPase1 and PECP1 for different substrates have been studied in vitro but require confirmation in planta. Here, we examined the in vivo function of both enzymes using a reverse genetics approach. We demonstrated that PPsPase1 and PECP1 affect plant phosphocholine and phosphoethanolamine content, but not the pyrophosphate-related phenotypes. These observations suggest that the enzymes play a similar role in planta related to the recycling of polar heads from membrane lipids that is triggered during phosphate starvation. Altering the expression of the genes encoding these enzymes had no effect on lipid composition, possibly due to compensation by other lipid recycling pathways triggered during phosphate starvation. F...
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The root cap has a fundamental role in sensing environmental cues as well as regulating root growth via altered meristem activity. Despite this well-established role in the control of developmental processes in roots, the root cap's... more
The root cap has a fundamental role in sensing environmental cues as well as regulating root growth via altered meristem activity. Despite this well-established role in the control of developmental processes in roots, the root cap's function in nutrition remains obscure. Here, we uncover its role in phosphate nutrition by targeted cellular inactivation or phosphate transport complementation in Arabidopsis, using a transactivation strategy with an innovative high-resolution real-time (33)P imaging technique. Remarkably, the diminutive size of the root cap cells at the root-to-soil exchange surface accounts for a significant amount of the total seedling phosphate uptake (approximately 20%). This level of Pi absorption is sufficient for shoot biomass production (up to a 180% gain in soil), as well as repression of Pi starvation-induced genes. These results extend our understanding of this important tissue from its previously described roles in environmental perception to novel func...
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Phosphate (Pi) is a macronutrient that is essential for plant life. Several regulatory components involved in phosphate homeostasis have been identified, revealing a very high complexity at the cellular and subcellular levels. Determining... more
Phosphate (Pi) is a macronutrient that is essential for plant life. Several regulatory components involved in phosphate homeostasis have been identified, revealing a very high complexity at the cellular and subcellular levels. Determining the phosphate content in plants is crucial to understanding this regulation, and short real-time (33)Pi uptake imaging experiments have shown Pi movement to be highly dynamic. Furthermore, gene modulation by phosphate is finely controlled by localization of this ion at the tissue as well as cellular and subcellular levels. Deciphering these regulations requires access to and quantification of the phosphate pool in the various plant compartments. This review presents the different techniques available to measure, visualize and trace phosphate in plants, with a discussion of the future prospects.
Research Interests: Chromatography, Plant Biology, Mass Spectrometry, Biology, Plant cell physiology, and 15 moreMagnetic Resonance Spectroscopy, Medicine, Imaging Techniques, Phosphorus, Plant, Plants, Pi, SIMS, Mineral Nutrition, Electrophoresis, Phosphates, Phosphate, Genetic Markers, Biosensing Techniques, and Biochemistry and cell biology
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Prior to the release of their cargoes into the vacuolar lumen, sorting endosomes mature into multivesicular bodies (MVBs) through the action of ENDOSOMAL COMPLEX REQUIRED FOR TRANSPORT (ESCRT) protein complexes. MVB-mediated sorting of... more
Prior to the release of their cargoes into the vacuolar lumen, sorting endosomes mature into multivesicular bodies (MVBs) through the action of ENDOSOMAL COMPLEX REQUIRED FOR TRANSPORT (ESCRT) protein complexes. MVB-mediated sorting of high-affinity phosphate transporters (PHT1) to the vacuole limits their plasma membrane levels under phosphate-sufficient conditions, a process that allows plants to maintain phosphate homeostasis. Here, we describe ALIX, a cytosolic protein that associates with MVB by interacting with ESCRT-III subunit SNF7 and mediates PHT1;1 trafficking to the vacuole in Arabidopsis thaliana. We show that the partial loss-of-function mutant alix-1 displays reduced vacuolar degradation of PHT1;1. ALIX derivatives containing the alix-1 mutation showed reduced interaction with SNF7, providing a simple molecular explanation for impaired cargo trafficking in alix-1 mutants. In fact, the alix-1 mutation also hampered vacuolar sorting of the brassinosteroid receptor BRI1....
Research Interests: Genetics, Metabolism, Plant Biology, Biology, Cell Biology, and 15 moreMedicine, Arabidopsis thaliana, Protein Kinases, Mutation, Plant, Biogenesis, Endosome, Protein Trafficking, Arabidopsis, Homeostasis, Phosphates, Plant cell, Membrane Protein, Protein Complexes, and Biochemistry and cell biology
Plants display numerous strategies to cope with phosphate (Pi)-deficiency. Despite multiple genetic studies, the molecular mechanisms of low-Pi-signalling remain unknown. To validate the interest of chemical genetics to investigate this... more
Plants display numerous strategies to cope with phosphate (Pi)-deficiency. Despite multiple genetic studies, the molecular mechanisms of low-Pi-signalling remain unknown. To validate the interest of chemical genetics to investigate this pathway we discovered and analysed the effects of PHOSTIN (PSN), a drug mimicking Pi-starvation in Arabidopsis. We assessed the effects of PSN and structural analogues on the induction of Pi-deficiency responses in mutants and wild-type and followed their accumulation in plants organs by high pressure liquid chromotography (HPLC) or mass-spectrophotometry. We show that PSN is cleaved in the growth medium, releasing its active motif (PSN11), which accumulates in plants roots. Despite the overaccumulation of Pi in the roots of treated plants, PSN11 elicits both local and systemic Pi-starvation effects. Nevertheless, albeit that the transcriptional activation of low-Pi genes by PSN11 is lost in the phr1;phl1 double mutant, neither PHO1 nor PHO2 are requ...