Publications by authors named "Caroline Broyart"

Plant endogenous signaling peptides shape growth, development and adaptations to biotic and abiotic stress. Here, we identify C-TERMINALLY ENCODED PEPTIDEs (CEPs) as immune-modulatory phytocytokines in Arabidopsis thaliana. Our data reveals that CEPs induce immune outputs and are required to mount resistance against the leaf-infecting bacterial pathogen Pseudomonas syringae pv.

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Article Synopsis
  • The hydrostatic skeleton of plants is formed by pressurized cells with strong walls, which rely on RAPID ALKALINIZATION FACTOR (RALF) peptides for assembly and expansion.
  • The RALF22 peptide plays a key role in root hair cell expansion by compacting pectin polymers and forming a complex with other proteins, triggering adaptive cellular responses.
  • This study reveals that RALF peptides serve both structural and signaling functions in plant cell wall organization, suggesting a broader application in various plant cell types.
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Microscale thermophoresis (MST) is a simple but powerful tool to study the in vitro interaction among biomolecules, and to quantify binding affinities. MST curves describe the change in the fluorescence level of a fluorescent target as a result of an IR-laser-induced temperature change. The degree and nature of the change in fluorescence signal depends on the size, charge, and solvation shell of the molecules, properties that change in function of the binding of a ligand to the fluorescent target.

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Article Synopsis
  • The assembly of specific cell wall polysaccharides is vital for plant growth and requires the complex of RAPID ALKALINIZATION FACTOR 4 (RALF4) and LEUCINE-RICH REPEAT EXTENSIN 8 (LRX8) for cell wall integrity during pollen tube development.
  • The LRX8-RALF4 complex has a unique heterotetrametric structure that interacts specifically with demethylesterified pectins, influenced by the charge of the RALF4's surface.
  • This interaction helps organize the cell wall polymers into a necessary reticulated network, highlighting RALF4's crucial dual role in both structural support and signaling during
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The membrane receptor kinases HAESA and HSL2 recognize a family of IDA/IDL signaling peptides to control cell separation processes in different plant organs. The homologous HSL1 has been reported to regulate epidermal cell patterning by interacting with a different class of signaling peptides from the CLE family. Here we demonstrate that HSL1 binds IDA/IDL peptides with high, and CLE peptides with lower affinity, respectively.

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Microbial and plant cell walls have been selected by the plant immune system as a source of microbe- and plant damage-associated molecular patterns (MAMPs/DAMPs) that are perceived by extracellular ectodomains (ECDs) of plant pattern recognition receptors (PRRs) triggering immune responses. From the vast number of ligands that PRRs can bind, those composed of carbohydrate moieties are poorly studied, and only a handful of PRR/glycan pairs have been determined. Here we present a computational screening method, based on the first step of molecular dynamics simulation, that is able to predict putative ECD-PRR/glycan interactions.

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Plant reproduction relies on the highly regulated growth of the pollen tube for sperm delivery. This process is controlled by secreted RALF signaling peptides, which have previously been shown to be perceived by RLK1-like (RLK1Ls) membrane receptor-kinases/LORELEI-like GLYCOLPHOSPHATIDYLINOSITOL (GPI)-ANCHORED PROTEINS (LLG) complexes, or by leucine-rich repeat (LRR) extensin proteins (LRXs). Here, we demonstrate that RALF peptides fold into bioactive, disulfide bond-stabilized proteins that bind the LRR domain of LRX proteins with low nanomolar affinity.

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The molecular mechanisms by which animals integrate external stimuli with internal energy balance to regulate major developmental and reproductive events still remain enigmatic. We investigated this aspect in the marine bristleworm, , a species where sexual maturation is tightly regulated by both metabolic state and lunar cycle. Our specific focus was on ligands and receptors of the gonadotropin-releasing hormone (GnRH) superfamily.

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Complex cell-to-cell communication between the male pollen tube and the female reproductive organs is required for plant fertilization. A family of Catharanthus roseus receptor kinase 1-like (CrRLK1L) membrane receptors has been genetically implicated in this process. Here, crystal structures of the CrRLK1Ls ANXUR1 and ANXUR2 are reported at 1.

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Article Synopsis
  • High salinity stress negatively affects plant growth, and trehalose metabolism may help improve stress tolerance, but the specific molecular mechanisms are still not fully understood.
  • Researchers found that AtTPPD, a key enzyme in trehalose metabolism in Arabidopsis thaliana, is localized in chloroplasts, and plants either lacking or overexpressing this enzyme show differing levels of salt stress tolerance, which is linked to sugar metabolism.
  • The study reveals that AtTPPD activity is regulated by redox status through certain cysteine residues, suggesting that similar regulatory mechanisms could exist across various plant types for adjusting to environmental challenges.
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The formation of abnormal isoaspartyl residues derived from aspartyl or asparaginyl residues is a major source of spontaneous protein misfolding in cells. The repair enzyme protein L: -isoaspartyl methyltransferase (PIMT) counteracts such damage by catalyzing the conversion of abnormal isoaspartyl residues to their normal aspartyl forms. Thus, this enzyme contributes to the survival of many organisms, including plants.

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Introduction: Maize mutants deficient for the expression of two genes encoding cytosolic glutamine synthetase (GS) isoenzymes GS1.3 and GS1.4 displayed reduced kernel number and kernel size, respectively, the effect of the mutation being cumulative in the double mutant.

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