Jean-Christophe Palauqui

Jean-Christophe Palauqui
French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · Department of Plant Biology

PhD

About

69
Publications
10,858
Reads
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4,592
Citations
Additional affiliations
April 1999 - present
French National Institute for Agriculture, Food, and Environment (INRAE)
Position
  • Researcher
April 1999 - present
French National Institute for Agriculture, Food, and Environment (INRAE)
Position
  • Senior Researcher

Publications

Publications (69)
Preprint
Noise plays a major role in cellular processes and in the development of tissues and organs. Several studies have examined the origin, the integration or the accomodation of noise in gene expression, cell growth and elaboration of organ shape. By contrast, much less is known about variability in cell division plane positioning, its origin and links...
Chapter
Unraveling the mechanisms that govern division plane orientation is a major challenge to understand plant development. In this respect, the Arabidopsis early embryo is a model system of choice since embryogenesis is relatively simple and cell division planes orientation is highly predictable. Here we present an integrated set of protocols to study...
Article
Full-text available
Very-long-chain fatty acids (VLCFAs) are essential for many aspects of plant development and necessary for the synthesis of seed storage triacylglycerols, epicuticular waxes, and sphingolipids. Identification of the acetyl-CoA carboxylase PASTICCINO3 and the 3-hydroxy acyl-CoA dehydratase PASTICCINO2 revealed that VLCFAs are important for cell prol...
Article
Full-text available
Background The vascular system of plants consists of two main tissue types, xylem and phloem. These tissues are organized into vascular bundles that are arranged into a complex network running through the plant that is essential for the viability of land plants. Despite their obvious importance, the genes involved in the organization of vascular ti...
Article
Full-text available
Background: Plant protoplasts are basic plant cells units in which the pecto-cellulosic cell wall has been removed, but the plasma membrane is intact. One of the main features of plant cells is their strong plasticity, and their propensity to regenerate an organism from a single cell. Methods and differentiation protocols used in plant physiology...
Article
Full-text available
Plant tissue architecture and organ morphogenesis rely on the proper orientation of cell divisions. Previous attempts to predict division planes from cell geometry in plants mostly focused on 2D symmetric divisions. Using the stereotyped division patterns of Arabidopsis thaliana early embryogenesis, we investigated geometrical principles underlying...
Preprint
Full-text available
Background: One of the main features of plant cells is their strong plasticity, and their propensity to regenerate an organism from a single cell. Plant protoplasts are basic plant cells units in which the pecto-cellulosic cell wall has been removed, but the plasma membrane is intact. One of the main features of plant cells is their strong plastici...
Book
Unraveling the mechanisms that govern division plane orientation is a major challenge to understand plant development. In this respect, the Arabidopsis early embryo is a model system of choice since embryogenesis is relatively simple and cell division planes orientation is highly predictable. Here, we present an integrated set of protocols to study...
Article
Unraveling the mechanisms that govern division plane orientation is a major challenge to understand plant development. In this respect, the Arabidopsis early embryo is a model system of choice since embryogenesis is relatively simple and cell division planes orientation is highly predictable. Here, we present an integrated set of protocols to study...
Article
The phloem is a vascular strand that conducts photoassimilates and systemic signals throughout the plant to coordinate growth. To date, few molecular genetic determinants have been identified to control both specification and differentiation of this tissue [1, 2 and 3]. Among them, OCTOPUS (OPS) protein was previously identified as a polarly locali...
Article
Full-text available
The molecular mechanisms by which vascular tissues acquire their identity are largely unknown. Here we report on the identification and characterization of VCC (VASCULATURE COMPLEXITY AND CONNECTIVITY), a member of a 15-member, plant-specific gene family in Arabidopsis thaliana that encodes proteins of unknown function with four predicted transmemb...
Article
Full-text available
Background The transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a repressor of seed germination acting downstream of the master repressor PHYTOCROME INTERACTING FACTOR3-LIKE 5 (PIL5). Among others, PIL5 induces the expression of the genes encoding the two DELLA proteins GA INSENSITIVE 1 (GAI) and REPRESSOR OF ga1-3 (RGA).ResultsBased on th...
Article
Full-text available
Embryo morphodynamics at early developmental stages of Arabidopsis thaliana has been studied. A pipeline has been elaborated from confocal microscopy and tissue 3D reconstruction to cell-lineage tracing and numerical simulation of growing embryo mechanics. Tentative results of its use are presented.
Article
Development of plant embryo beginning from the very early stages is not fully studied yet. For example, detailed description of dynamics of cellular composition of embryo, and the cells growth are unknown. Herein we propose a quantitative description of the early Arabidopsis thaliana development. The description is quantitative with respect to cell...
Article
Full-text available
In response to plant proximity or canopy shade, plants can react by altering elongation growth and development. Several members of the class II homeodomain-leucine zipper (HD-ZIPII) transcription factor family have been shown to play an instrumental role in the responses to shade. HD-ZIP members of the class III (HD-ZIPIII), by contrast, are involv...
Article
Unlike the situation in animals, the final morphology of the plant body is highly modulated by the environment. During Arabidopsis development, intrinsic factors provide the framework for basic patterning processes. CLASS III HOMEODOMAIN LEUCINE ZIPPER (HD-ZIPIII) transcription factors are involved in embryo, shoot and root patterning. During veget...
Article
Full-text available
Vascular development is embedded into the developmental context of plant organ differentiation and can be divided into the consecutive phases of vascular patterning and differentiation of specific vascular cell types (phloem and xylem). To date, only very few genetic determinants of phloem development are known. Here, we identify OCTOPUS (OPS) as a...
Article
Full-text available
Acyl chain length is thought to be crucial for biophysical properties of the membrane, in particular during cell division, when active vesicular fusion is necessary. In higher plants, the process of cytokinesis is unique, because the separation of the two daughter cells is carried out by de novo vesicular fusion to generate a laterally expanding ce...
Article
How are the regular patterns of organs established along a plant stem and how are the transitions between different patterns regulated? Now genes of the PLETHORA family have been shown to modulate these transitions by fine-tuning the mechanisms of polar transport of auxin, a key effector of organogenesis.
Article
Full-text available
Sphingolipids are a class of structural membrane lipids involved in membrane trafficking and cell polarity. Functional analysis of the ceramide synthase family in Arabidopsis thaliana demonstrates the existence of two activities selective for the length of the acyl chains. Very-long-acyl-chain (C > 18 carbons) but not long-chain sphingolipids are e...
Data
Full-text available
NOF1 expression pattern. Electronic pictographic representations of NOF1 expression patterns. Data analysis was performed using the the tools of the Bio-Array Resource at http://bar.utoronto.ca. (Winter et al., 2007). (0.16 MB PDF)
Data
Full-text available
Co-expression Analyses. Functional classification of genes according to MIPS database. A) best 100 genes co-expressed with NOF1 (input set N = 102, classified set N = 99, Atgene express tissue set) B) random list of Arabidopsis genes (input set N = 100, classified set N = 99) C) random list of Arabidopsis genes (input set N = 1000, classified set N...
Data
Predicted network of NOF1 (At1g17690) partners. The network was build using the interaction viewer program http://bar.utoronto.ca/interactions/cgi-bin/arabidopsis_interactions_viewer.cgi. (Toufighi et al., 2005). At5g16750 Toz (TORMOZ), At2g43650 EMB2777(SAS10), At2G47990 EDA13 (SWA1 Slow Walker, UTP15), At5g66540 AtMPP10, At5g15750 AtIMP4, At4g256...
Data
Full-text available
Cytological analysis of nof 1-1 embryos. A) 3D reconstructions of young embryos show defaults in cell divisions as figured onto (c) when compared to WT (a). Globular embryos show division abnormalities in the hypophysis (d,e, f) as well as in the suspensor cells, both in transverse and lengthways orientations. Bar = 10 µM B) Mature dry seeds observ...
Data
Full-text available
Reciprocal crosses between hemizygous nof1 and WT plants: occurrence of embryo lethal phenotype and segregation of the Kanamycin resistance marker. A–B–C–D: Controls. Crossing hemizygous mutants with the wild type plants, no embryo phenotypes are expected. The observed dead seeds are naturally aborted seeds usually found in wild-type siliques and/o...
Data
Full-text available
Embryo phenotypes. A) Phenotypes of nof1-1 embryos. Seeds were dissected after 1 hour of imbibition on whatman paper. Development ranges from globular (1) to almost fully shaped (2) embryos. B) Embryo viability using tetrazolium test (Boisson et al. 2001). Results shown are obtained with WT embryo (b) nof1-1 embryo (c and d) and wild type embryo bo...
Data
Full-text available
Phenotypes of nof1-2 ovules. Siliques were dissected and cleared for DIC observations. A) row of developing ovules and B) an enlargement of the nuclei. Nuclei c–d and e exhibit typical figures of fertilized ovules whereas ovules a and b are blocked at the 4 nuclei stage of the megagametogenesis. Bar = 10 µm. (2.35 MB PDF)
Data
Full-text available
Complementation of the nof1 mutations. The presence of the nof1-1 or nof1-2 T-DNA insertions was demonstrated in the progenies of transgenic seedlings by PCR using specific primers for nof1-1 or nof1-2 insertions (Up/RB and 2821/LB3, respectively). Kanamycin resistance of the seedlings is provided by the nof1 mutations (see table S4) and hygromycin...
Data
Segregation of the Kanamycin marker in the progenies of nof mutants. Cytological analyses suggesting that the mutations are embryo lethal, this hypothesis has been tested (H0 = the segregation is 2Kr/1Ks). In both cases, the observed X2> X2 theoritical at 5% (3,84). The data showed that the number of resistant seedlings is lower than expected for e...
Article
Full-text available
The control of ribosomal RNA biogenesis is essential for the regulation of protein synthesis in eukaryotic cells. Here, we report the characterization of NOF1 that encodes a putative nucleolar protein involved in the control of rRNA expression in Arabidopsis. The gene has been isolated by T-DNA tagging and its function verified by the characterizat...
Article
Full-text available
Despite the wide spread application of confocal and multiphoton laser scanning microscopy in plant biology, leaf phenotype assessment still relies on two-dimensional imaging with a limited appreciation of the cells' structural context and an inherent inaccuracy of cell measurements. Here, a successful procedure for the three-dimensional imaging and...
Data
Image stack of an Arabidopsis leaf near the end of leaf blade expansion. Optical sectioning of an Arabidopsis Col-4 leaf 6 at 16 days after initiation (16 h photoperiod) using multiphoton microscopy.
Data
Image stack of an apple leaf early in leaf blade expansion. Optical sectioning of the third leaf from the top of an apple graft (Granny Smith) using multiphoton microscopy.
Data
Image stack of a fully expanded apple leaf. Optical sectioning of the ninth leaf from the top of an apple graft (Granny Smith) using multiphoton microscopy.
Data
Image stack of an Arabidopsis leaf early in leaf blade expansion. Optical sectioning of an Arabidopsis Col-4 leaf 6 at 9 days after initiation (16 h photoperiod) using multiphoton microscopy.
Data
Three-dimensional imaging of apple leaves using multiphoton microscopy. (a) Single optical sections in, from left to right, the adaxial epidermis, the palisade mesophyll, the spongy mesophyll and the abaxial epidermis, taken from an image stack of a young (the first unfolded leaf on the axis of a Starkrimson graft, top row) and mature apple leaf (t...
Data
Three-dimensional imaging of Arabidopsis leaves using multiphoton microscopy. Single optical sections in, from top to bottom, the adaxial epidermis, the palisade mesophyll, the spongy mesophyll and the abaxial epidermis, taken from image stacks of leaf 6 of the Arabidopsis rosette at 8-22 days after initiation (dai).
Article
Full-text available
Very-long-chain fatty acids (VLCFAs) are essential for many aspects of plant development and necessary for the synthesis of seed storage triacylglycerols, epicuticular waxes, and sphingolipids. Identification of the acetyl-CoA carboxylase PASTICCINO3 and the 3-hydroxy acyl-CoA dehydratase PASTICCINO2 revealed that VLCFAs are important for cell prol...
Article
Full-text available
Building on previous work, we further developed a staining procedure that fluorescently labels plant cell walls and, when combined with confocal microscopy, allows visualization of plant cellular organisation in whole mounts to depths exceeding 200 microm. This technique can be combined with beta-glucuronidase histochemical activity assays, allowin...
Article
Building on previous work, we further developed a staining procedure that fluorescently labels plant cell walls and, when combined with confocal microscopy, allows visualization of plant cellular organisation in whole mounts to depths exceeding 200 μm. This technique can be combined with β-glucuronidase histochemical activity assays, allowing the s...
Article
Full-text available
Currently, examination of the cellular structure of plant organs and the gene expression therein largely relies on the production of tissue sections. Here, we present a staining technique that can be used to image entire plant organs using confocal laser scanning microscopy. This technique produces high-resolution images that allow three-dimensiona...
Article
Full-text available
During Arabidopsis embryogenesis, procambial cells undergo coordinated, asymmetric cell divisions, giving rise to vascular precursor cells (protophloem and protoxylem precursors). After germination, these cells terminally differentiate into specialized conducting cells, referred to as protophloem and protoxylem cells. Few readily identifiable marke...
Article
Little is known about the molecular processes involved in the phloem response to aphid feeding. We investigated molecular responses to aphid feeding on celery (Apium graveolenscv. Dulce) plants infested with the aphid Myzus persicae, as a means of identifying changes in phloem function. We used celery as our model species as it is easy to separate...
Article
Events occurring in the phloem tissue are key to understanding a wide range of developmental and physiological processes in vascular plants. While a considerable amount of molecular information on phloem proteins has emerged in the past decade, a unified picture of the molecular mechanisms involved in phloem differentiation and function is still la...
Article
Full-text available
Phloem protein 2 (PP2) is one of the most abundant and enigmatic proteins in the phloem sap. Although thought to be associated with structural P-protein, PP2 is translocated in the assimilate stream where its lectin activity or RNA-binding properties can exert effects over long distances. Analyzing the diversity of these proteins in vascular plants...
Article
In plants, post-transcriptional gene silencing results in RNA degradation after transcription. Among tobacco transformants carrying a nitrate reductase (Nia) construct under the control of the cauliflower mosaic virus 35S promoter (35S-Nia2), one class of transformants spontaneously triggers Nia post-transcriptional gene silencing (class II) wherea...
Article
Cucumber mosaic cucumovirus (CMV) infection but not tomato black ring nepovirus infection counteracted post-transcriptional gene silencing (PTGS) of nitrate reductase (Nia) or beta-glucuronidase (uidA) transgenes in newly developing leaves of tobacco and Arabidopsis plants. PTGS did not affect meristems of noninfected silenced plants, indicating th...
Article
Full-text available
Post-transcriptional gene silencing (cosuppression) results in the degradation of RNA after transcription. A transgenic Arabidopsis line showing post-transcriptional silencing of a 35S-uidA transgene and uidA-specific methylation was mutagenized using ethyl methanesulfonate. Six independent plants were isolated in which uidA mRNA accumulation and b...
Article
Full-text available
Cosuppression results in the degradation of RNA from host genes and homologous transgenes after transcription in the nucleus. By using grafting experiments, we have shown previously that a systemic signal mediates the propagation of cosuppression of Nia host genes and 35S-Nia2 transgenes from silenced 35S-Nia2 transgenic stocks to nonsilenced 35S-N...
Article
Full-text available
Using tobacco nitrate reductase cosuppression as a model system of post-transcriptional gene silencing, we analyzed the influence of DNA and RNA dosages both together and independently. For this purpose, zero, one, two, or four active or transcriptionally silenced copies of a cauliflower mosaic virus 35S-Nia2 transgene were combined by transformati...
Article
Full-text available
Using grafting procedures, we investigated the transmission of co-suppression of nitrate reductase and nitrite reductase host genes and transgenes and of post-transcriptional silencing of a uidA transgene encoding glucuronidase in tobacco. We demonstrate that silencing is transmitted with 100% efficiency from silenced stocks to non-silenced scions...
Article
Full-text available
Frequencies, timing, and spatial patterns of co-suppression of the nitrate (Nia) and nitrite (Nii) genes were analyzed in transgenic tobacco (Nicotiana tabacum) plants carrying either Nia or Nii cDNAs under the control of the 35S promoter, or a Nii gene with its own regulatory signals (promoter, introns, and terminator) cloned downstream of two cop...
Article
Nitrate assimilation is a fundamental function in any plant including those that can fix atmospheric nitrogen in symbiosis with soil bacteria. In recent years, attempts have been made to understand the biological significance of the complex regulation of this pathway using genetic engineering techniques. Transgenic plants that either over- or under...
Article
Co-syppression of host genes and 35S transgenes encoding nitrate reductase was previously reported in transgenic tobacco plants (Nicotiana tabacum cv. Paraguay or Burley) using either a full-length cDNA or fragments devoid of the 3′ and/or 5′ UTR. Co-suppression was previously shown to affect a limited fraction of the progeny of one transgenic toba...
Article
Silencing of Nia host genes and transgenes (encoding nitrate reductase) was previously achieved by introducing into tobacco plants the tobacco Nia2 cDNA cloned downstream of the cauliflower mosaic virus (CaMV) 35S promoter. To check whether Nii host genes and transgenes (encoding nitrite reductase, the second enzyme of the nitrate assimilation path...

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