1,725,736 research outputs found
EFR-Mediated Innate Immune Response in Arabidopsis thaliana is a Useful Tool for Identification of Novel ERQC Modulators.
No full textPlants offer a simpler and cheaper alternative to mammalian animal models for the study of endoplasmic reticulum glycoprotein folding quality control (ERQC). In particular, the Arabidopsis thaliana (At) innate immune response to bacterial peptides provides an easy means of assaying ERQC function in vivo. A number of mutants that are useful to study ERQC in planta have been described in the literature, but only for a subset of these mutants the innate immune response to bacterial elicitors has been measured beyond monitoring plant weight and some physio-pathological parameters related to the plant immune response. In order to probe deeper into the role of ERQC in the plant immune response, we monitored expression levels of the Phosphate-induced 1 (PHI-1) and reticulin-oxidase homologue (RET-OX) genes in the At ER α-Glu II rsw3 and the At UGGT uggt1-1 mutant plants, in response to bacterial peptides elf18 and flg22. The elf18 response was impaired in the rsw3 but not completely abrogated in the uggt1-1 mutant plants, raising the possibility that the latter enzyme is partly dispensable for EF-Tu receptor (EFR) signaling. In the rsw3 mutant, seedling growth was impaired only by concomitant application of the At ER α-Glu II NB-DNJ inhibitor at concentrations above 500 nM, compatibly with residual activity in this mutant. The study highlights the need for extending plant innate immune response studies to assays sampling EFR signaling at the molecular level
Émotion, expérience et histoire. Entretien avec la médiéviste Piroska Nagy
No full textPiroska Nagy ©EFR – CC-by-nc Piroska Nagy est professeure d’histoire médiévale à l'Université du Québec à Montréal. Entre anthropologie historique et histoire sociale des concepts, elle s'intéresse aux structures de l’affectivité médiévale et ses représentations, aux rapports des réalités affectives avec le corps, la raison et les cinq sens dans le contexte religieux du Moyen Âge central (XIe-XIIIe s.). De janvier à avril 2023, elle est accueillie à l'EFR et travaille sur le projet de rech..
EFR-Mediated Innate Immune Response in Arabidopsis thaliana is a Useful Tool for Identification of Novel ERQC Modulators.
No full textPlants offer a simpler and cheaper alternative to mammalian animal models for the study of endoplasmic reticulum glycoprotein folding quality control (ERQC). In particular, the Arabidopsis thaliana (At) innate immune response to bacterial peptides provides an easy means of assaying ERQC function in vivo. A number of mutants that are useful to study ERQC in planta have been described in the literature, but only for a subset of these mutants the innate immune response to bacterial elicitors has been measured beyond monitoring plant weight and some physio-pathological parameters related to the plant immune response. In order to probe deeper into the role of ERQC in the plant immune response, we monitored expression levels of the Phosphate-induced 1 (PHI-1) and reticulin-oxidase homologue (RET-OX) genes in the At ER α-Glu II rsw3 and the At UGGT uggt1-1 mutant plants, in response to bacterial peptides elf18 and flg22. The elf18 response was impaired in the rsw3 but not completely abrogated in the uggt1-1 mutant plants, raising the possibility that the latter enzyme is partly dispensable for EF-Tu receptor (EFR) signaling. In the rsw3 mutant, seedling growth was impaired only by concomitant application of the At ER α-Glu II NB-DNJ inhibitor at concentrations above 500 nM, compatibly with residual activity in this mutant. The study highlights the need for extending plant innate immune response studies to assays sampling EFR signaling at the molecular level
Plongée dans la Rome médiévale et moderne
No full textRetours sur l’atelier de formation à la recherche École française de Rome en partenariat avec l'Académie de France à Rome-Villa Médicis, le Museo Nazionale Romano, la Biblioteca apostolica vaticana, l'Archivum Romanum Societatis lesu, l’Archivio storico della Penitenzieria Apostolica et le convento di Santa Sabina all'Aventino Visite de la Villa Médicis. ©Lana Martysheva / EFR - CC-by-nc. Chaque année, l’École française de Rome propose un atelier de formation à la recherche pour les ma..
Identification of receptor complex components and receptor activation mechanisms in plant innate immunity
Full text linkPlants rely on an innate immune system which successfully recognizes and restricts pathogenic microbes. The key for this defense is the detection of pathogen derived non-self signatures and endogenous elicitors released during a microbial attack.
Here we report the identification of PEPR2, a new receptor for endogenous elicitors in Arabidopsis (chapter 1). Together with its homologue PEPR1 it functions redundantly in the recognition of AtPep1, a plant derived peptide released during wounding and pathogen defense. Our analysis showed that the defense signaling triggered upon AtPep1 stimulation exhibits strong similarity to the response to microbe derived elicitors.
For detection of pathogen derived elicitors the flagellin perception through the receptor FLS2 evolved as model system in plants. FLS2 is known to function together with an associated receptor-like kinase referred to as SERK3/BAK1. In an in vitro analysis of the FLS2-kinase and the BAK1-kinase we were able to show, that FLS2 is a substrate for the BAK1-kinase. This indicates that BAK1 acts as upstream kinase, which phosphorylates and activates the receptor upon dimerization (chapter 2). Using a mass spectrometric analysis on immunopurified FLS2 protein we identified one elicitor independent and one elicitor dependent putative phosphorylation site. The position of both sites suggests a role for phosphorylation in the regulation of ubiquitination and endocytosis.
We further analyzed the impact of receptor kinase activity by a characterization of a kinase inactive version of the EF-Tu receptor EFR (chapter 3). This analysis verified that also EFR functions through BAK1 and demonstrated that kinase activity of the receptor is not required for formation of the EFR/BAK1 complex. Strikingly, kinase inactive EFR was able to initiate an elicitor dependent ethylene accumulation and conferred partial resistance to Agrobacterium tumefaciens, while other signaling events were absent. This finding revealed a diverging signaling network in which not all pathways require receptor kinase activity to get activated.
By immunopurification and subsequent mass spectrometric analysis of FLS2 protein we further explored this signaling system and its components. Importantly we found not only BAK1, but also its paralogues SERK1, SERK2, SERK4 and SERK5 to co-purify with the flagellin receptor, which indicates a redundant function of these proteins (chapter 4). We also identified several isoforms of the family of 14-3-3 general regulating factors. This is in line with an in silico analysis of the FLS2 sequence, which predicted the putative phosphorylation site S 1078 to operate as 14 3 3 protein binding site. Another group of proteins which co-purified with FLS2 in an elicitor dependent manner comprises RAB-GTPases and SNARE proteins. These protein factors are known to control vesicle fusion events. Since bacterial infections trigger focal secretion, we speculate that the elicitor activated FLS2 complex might lead secretory vesicles directly to the site of infection.
Taken together this works provides new insight into different levels of plant immunity. This includes not only the identification of a new receptor and receptor associated proteins, but also adds new aspects to our understanding of receptor activation and downstream signaling. Therefore these results provide a basis to further investigate plant innate immunity on the whole
Une mémoire farnésienne. Entretien avec André Vauchez 1/3
No full textAndré Vauchez, août 2023, Barbâtre (Noirmoutier) ©Chloé Tardivel / EFR André Vauchez est médiéviste, ancien membre de l’École française de Rome (1965-1968), premier directeur de la section Moyen Âge (1972-1979) et ancien directeur (1995-2003). Il est spécialiste d’histoire de la vie religieuse et de la spiritualité médiévales. Il est l'auteur notamment de La sainteté en Occident aux derniers siècles du Moyen Age (1198-1431) d’après les procès de canonisation et les documents hagiographique..
The Arabidopsis pattern recognition receptor EFR enhances fire blight resistance in apple
Full text linkFire blight disease, caused by the bacterium Erwinia amylovora (E. amylovora), is responsible for substantial losses in cultivated apples worldwide. An important mechanism of plant immunity is based on the recognition of conserved microbial molecules, named pathogen-associated or microbe-associated molecular patterns (PAMPs or MAMPs), through pattern recognition receptors (PRRs), leading to pattern-triggered immunity (PTI). The interspecies transfer of PRRs represents a promising strategy to engineer broad-spectrum and durable disease resistance in crops. EFR, the Arabidopsis thaliana PRR for the PAMP elf18 derived from the elongation factor thermal unstable (EF-Tu) proved to be effective in improving bacterial resistance when expressed into Solanaceae and other plant species. In this study, we tested whether EFR can affect the interaction of apple with E. amylovora by its ectopic expression in the susceptible apple rootstock M.26. Stable EFR expression led to the activation of PAMP-triggered immune response in apple leaves upon treatment with supernatant of E. amylovora, as measured by the production of reactive oxygen species and the induction of known defense genes. The amount of tissue necrosis associated with E. amylovora infection was significantly reduced in the EFR transgenic rootstock compared to the wild-type. Our results show that the expression of EFR in apple rootstock may be a valuable biotechnology strategy to improve the resistance of apple to fire blight
Characteristics of EFR and functional residues.
No full textEFR (dark blue) and LFR (light blue) are compared to functional (dark orange) and non-functional (light orange) residues. The notch of a box corresponds to the confidence interval around its median: two notches which do not overlap indicate a difference of medians. (A) EFR show lower computed energies than they are in contact with many residues and tend to be embedded in the hydrophobic core. In contrast, functional residues are exposed to the solvent in order to constitute e.g. binding sites. (B) Hydrophobic interactions occur especially in the core of a protein, thus, most residues do not form any. However, EFR show a significant increase compared to LFR. (C) The clustering coefficient of a node describes how well-connected its adjacent nodes are. EFR connect regions of a protein which are separated at sequence level and, thus, are not well-connected on their own. Functional residues exhibit higher clustering coefficient indicating a more connected set of adjacent nodes.</p
EFR interacts with the XA21-signaling components XB24 and OsSERK2.
No full text<p>(A) Yeast two-hybrid assay between EFR (674-1032aa) intracellular domain (ID) and OsSERK2 ID (260-628aa), XB3 full-length (FL) (1-450aa), XB15 FL (1-639aa) and XB24 FL (1-198aa). EFR(D-N) indicates a mutation of the catalytic aspartate (D) 848aa to asparagine (N). The blue color indicates nuclear interaction between the two co-expressed proteins. Expression of all fusion proteins was confirmed by western blot analysis as shown in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004809#ppat.1004809.s015" target="_blank">S15 Fig</a>. (B) <i>In planta</i> interaction of EFR::GFP and XB24::FLAG in <i>N</i>. <i>benthamiana</i>. EFR::GFP and XB24::FLAG were transiently co-expressed in <i>N</i>. <i>benthamiana</i> leaves. Leaves were mock treated with water (-) or with 100 nM elf18<sub><i>E</i>.<i>coli</i></sub> for 10 min. Immuno-complexes were precipitated (IP) with GFP-Trap agarose beads. Proteins were separated and detected by SDS-PAGE electrophoresis followed by western blot analysis with HRP-conjugated anti-GFP or anti-FLAG. (C) EFR::GFP or EFR::XA21::GFP form constitutive ligand-independent complexes with OsSERK2 <i>in vivo</i> without quantitative changes of the interaction within 15 min of elf18<sub><i>E</i>.<i>coli</i></sub> treatment. Immuno-complexes were precipitated from leaf material of <i>Ubi</i>::<i>EFR</i>::<i>GFP</i>-9-11-12 and <i>Ubi</i>::<i>EFR</i>::<i>XA21</i>::<i>GFP</i>-3-6-7 expressing rice plants treated with 1 μM elf18<sub><i>E</i>.<i>coli</i></sub> for the indicated time using GFP-trap beads. Kitaake rice leaves were used as negative control. Components of the immuno-precipitated complexes were separated by SDS-PAGE gel followed by immuno-detection with anti-GFP (for EFR::GFP and EFR::XA21::GFP) and anti-OsSERK2 (for OsSERK2). EFR::GFP and EFR::XA21::GFP gives rise to a signal at about 175 kDa. OsSERK2 (~70 kDa) was co-immunoprecipitated with EFR::GFP and EFR::XA21::GFP in the absence of elf18<sub><i>E</i>.<i>coli</i></sub> treatment. The lower panel shows equal amounts of OsSERK2 in both total protein fractions before immunoprecipitation. This experiment was repeated twice with similar results.</p
Brug Zephyr Reform Kravetoj og De sparer Penge, P.J. Efr.
No full textBRUG ZEPHYR REFORM KRAVETOJ OG DE SPARER PENGE, P.J. EFR.
Brug Zephyr Reform Kravetoj og De sparer Penge, P.J. Efr. ( -
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