Plasma Membrane Dynamics in Plant-Microbe Interactions
Constitutive expression of clathrin hub hinders elicitor-induced clathrin-mediated endocytosis and defense gene expression in plant cells.
International audience; Endocytosis has been recently implicated in the signaling network associated with the recognition of microbes by plants. In a previous study, we showed that the elicitor cryptogein was able to induce clathrin-mediated endocytosis (CME) in tobacco suspension cells. Herein, we investigate further the induced CME by means of a GFP-tagged clathrin light chain and a CME inhibitor, the hub domain of clathrin heavy chain. Hub constitutive expression does affect neither cell growth nor constitutive endocytosis but abolishes cryptogein-induced CME. Such an inhibition has no impact on early events in the cryptogein signaling pathway but reduces the expression of defense-associ…
Identification of putative interactors of arabidopsis sugar transporters
Identification of Putative Interactors of Arabidopsis Sugar Transporters
International audience; Hexoses and disaccharides are the key carbon sources for essentially all physiological processes across kingdoms. In plants, sucrose, and in some cases raffinose and stachyose, are transported from the site of synthesis in leaves, the sources, to all other organs that depend on import, the sinks. Sugars also play key roles in interactions with beneficial and pathogenic microbes. Sugar transport is mediated by transport proteins that fall into super-families. Sugar transporter (ST) activity is tuned at different levels, including transcriptional and posttranslational levels. Understanding the ST interactome has a great potential to uncover important players in biologi…
Perception of elicitins by receptor complex in solanaceae
Extensive infections of crop plants by plant pathogens have repeatedly resulted in catastrophic harvest failures causing major economic and social problems worldwide. Successful plant defence against pathogens is based on early microbe recognition and fast activation of downstream immune signalling (e.g. phosphorylations, production of reactive oxygen species, transcriptomic reprogramming). Plant surface pattern-recognition receptors (PRRs) act as initial detectors that can recognise microbial-associated molecular patterns (MAMPs) to induce the basal resistance response called MAMP-triggered immunity (MTI). Despite the increasing number of PRRs discovered in the past 20 years, for most of t…
The arbuscular mycorrhizal transportome, what next!
International audience; Understanding how arbuscular mycorrhizal (AM) symbioses establish and function is one of the most important current challenges in microbial ecology. Despite the fact that the AM symbiosis requires some complex and fine molecular tuning among symbionts in order to take place, both partners benefit from each other in a number of ways. For instance, the availability, uptake and exchange of nutrients in this biotrophic interaction are key factors driving plant growth and modulating biomass allocation. This underground trade is regulated by both plant and fungal transport components [1], as for instance the long distance transport of photosynthates from leaves towards col…
Induction des mécanismes de défense des plantes : Les acquis du modèle tabac/cryptogéine
Cryptogein is a small protein secreted by the oomycete Phytophthora cryptogea, able to trigger on tobacco plants both the developmenl of an hypersensitive response and the induction of resistance against a wide range of pathogens. The deciphering of molecular events associated with this process, using tobacco as a model plant, gave significant informations about the set up of defense mechanisms. The role of plasma membrane dynamics in such a signal transduction has been evidenced. ln particular; the presence of plasma membrane microdomains concentrating signaling proteins, and the modification of the proteic content of these domains upon cryptogein treatment have been demonstrated. Moreover…
Rôle de la dynamique de la membrane plasmique dans la mise en place des réactions de défense chez le tabac
The binding of cryptogein, a plant defense elicitor secreted by an oomycete, to an unknown receptor triggers well-known biochemical events of early signal transduction at the plasma membrane of tobacco cells. One of these early events is the transient production of Reactive Oxygen Species (ROS) by an NADPH oxidase, NtrbohD. We were thus interested to analyze the dynamic of the plasma membrane during these early stages. We determined that internalization of the endocytotic marker FM4-64 is stimulated a few minutes after addition of cryptogein to tobacco BY-2 cells. This stimulation is specific to the signal transduction pathway elicited by cryptogein since a lipid transfer protein, which bin…
Analyse des interactions trophiques entre les plantes et les microorganismes par des biosenseurs de sucres
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Cryptogein treatment stimulates clathrin-endocytosis correlated with ROS production in tobacco cells
International audience; During plant pathogen interactions, specific molecules elicit defense response of plant cells. Cryptogein, an elicitin produced by the pathogenic fungus Phytophtora cryptogea, induces a hypersensitive response (HR) in tobacco plants. The mode of action for cryptogein starts with recognition of this elicitor by an unidentified plasma membrane (PM) receptor. This ligand-receptor binding trigger a cascade of events at the PM level including rapid calcium influx, ions effluxes, extracellular medium alcalinization and plasma membrane depolarization both in tobacco plants and suspension cells. These events lead to the activation of plasma membrane-bound NADPH oxidase, Ntrb…
Clathrin-mediated endocytosis: an early event triggered by an elicitor of defence reaction in tobacco
International audience
Regulation of endocytosis by external stimuli in plant cells
International audience; Endocytosis is an essential process for the normal growth and development of eukaryotic cells. This mini-review presents an overview of endocytosis regulation in challenging environmental conditions such as nutrient availability, hormonal treatment or abiotic/biotic stress in plant cells. Recent data establishing a relationship between endocytosis and reactive oxygen species (ROS) production are also discussed.
Internalisation de la cryptogéine dans des cellules de tabac Nicotiana tabacum, cv Bright Yellow 2 (BY-2)
SPEBAPIPMUBINRA; Internalisation de la cryptogéine dans des cellules de tabac [i]Nicotiana tabacum[/i], cv Bright Yellow 2 (BY-2). 7. Journées Scientifiques et Techniques du Réseau des Microscopistes de l'INRA (RμI)
Dynamics of sugar transports in tobacco-microbe interactions
In vivoanalysis of the lumenal binding protein (BiP) reveals multiple functions of its ATPase domain
International audience; The endoplasmic reticulum (ER) chaperone binding protein (BiP) binds exposed hydrophobic regions of misfolded proteins. Cycles of ATP hydrolysis and nucleotide exchange on the ATPase domain were shown to regulate the function of the ligand-binding domain in vitro. Here we show that ATPase mutants of BiP with defective ATP-hydrolysis (T46G) or ATP-binding (G235D) caused permanent association with a model ligand, but also interfered with the production of secretory, but not cytosolic, proteins in vivo. Furthermore, the negative effect of BiP(T46G) on secretory protein synthesis was rescued by increased levels of wild-type BiP, whereas the G235D mutation was dominant. U…
Dynamic changes in the subcellular distribution of the tobacco ROS-producing enzyme RBOHD in response to the oomycete elicitor cryptogein.
Highlight text The oomycete elicitor cryptogein triggers the relocation of RBOHD from intracellular compartments to the plasma membrane in tobacco cells. This suggests that intracellular trafficking is a potential determinant of RBOHD activity.
Rôle des microdomaines du plasmalemme dans la réponse de la cellule végétale au stress biotique
National audience
Dynamique membranaire dans les réponses précoces des cellules de tabac à la cryptogéine
The Plant Defense Elicitor Cryptogein Stimulates Clathrin-Mediated Endocytosis Correlated with Reactive Oxygen Species Production in Bright Yellow-2 Tobacco Cells
Abstract The plant defense elicitor cryptogein triggers well-known biochemical events of early signal transduction at the plasma membrane of tobacco (Nicotiana tabacum) cells, but microscopic observations of cell responses related to these early events were lacking. We determined that internalization of the lipophilic dye FM4-64, which is a marker of endocytosis, is stimulated a few minutes after addition of cryptogein to tobacco Bright Yellow-2 (BY-2) cells. This stimulation is specific to the signal transduction pathway elicited by cryptogein because a lipid transfer protein, which binds to the same receptor as cryptogein but without triggering signaling, does not increase endocytosis. To…
Exocytosis and endocytosis act together to modify the plasma membrane order in cryptogein-elicited tobacco cells
SPEIPMUBINRA; Exocytosis and endocytosis act together to modify the plasma membrane order in cryptogein-elicited tobacco cells. 19. European Network for Plant Endomembrane Research meeting
Rôle de la dynamique de la membrane plasmique dans la mise en place des réactions de défense chez le tabac
National audience; Lors des interactions entre les plantes et les microorganismes, des molécules spécifiques élicitent les réponses de défense des cellules végétales. La cryptogéine, une élicitine produite par l’oomycète Phytophtora cryptogea, induit une réponse hypersensible (HR) et une résistance non systémique chez le tabac (1). Aussi bien sur plante entière que sur suspension cellulaire, la reconnaissance au niveau de la membrane plasmique et la fixation de cet éliciteur par un récepteur non identifié déclenche une cascade d’événements au niveau de la membrane plasmique comme un influx rapide de calcium, des efflux d’ions, une alcalinisation extracellulaire. De plus, une NADPH oxydase, …
Mécanismes cellulaires et moléculaires et ingénierie écologique des mycorhizes à arbuscules
SPEIPM; La mycorhize à arbuscules (MA) est une symbiose mutualiste entre des champignons telluriques (Gloméromycètes) et 80% des plantes terrestres, dont la majorité des plantes de culture. Elle est apparue il y a environ 475 millions d’années. Ce chapitre synthétise les connaissances actuelles sur les systèmes de transport impliqués dans les échanges de nutriments (avec un accent mis sur les échanges de carbone, azote, phosphate et soufre) entre les deux partenaires, ainsi que le prélèvement de ces nutriments par le champignon depuis le sol. Le chapitre adresse également le potentiel en ingénierie écologique de la MA dans le cadre d’une agriculture agroécologique.
Plasma membrane protein trafficking in plant-microbe interactions: a plant cell point of view
International audience; In order to ensure their physiological and cellular functions, plasma membrane (PM) proteins must be properly conveyed from their site of synthesis, i.e., the endoplasmic reticulum, to their final destination, the PM, through the secretory pathway. PM protein homeostasis also relies on recycling and/or degradation, two processes that are initiated by endocytosis. Vesicular membrane trafficking events to and from the PM have been shown to be altered when plant cells are exposed to mutualistic or pathogenic microbes. In this review, we will describe the fine-tune regulation of such alterations, and their consequence in PM protein activity. We will consider the formatio…
Membrane trafficking in immune singalin of plants
Throughout their life, plants face with a vast diversity of beneficial and pathogenicmicrobes. Following microbe recognition, whatever the outcome of the interaction,intensive changes in membrane vesicle trafficking to and from the plasma membraneoccur. This allows plant cells to modify the spatio-temporal distribution and/or theactivity of membrane proteins, influencing their molecular dialogue with microbes. Asexample, a secreted protein from the oomycete Phytophthora cryptogea elicitsdefense reactions against pathogens by a transcriptional reprogramming and celldeath of tobacco cells. In early steps, the microbe protein stimulates clathrin-mediated endocytosis and plasma membrane reorgan…