0000000001026177
AUTHOR
Karim Bouhidel
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…
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…
TIP family aquaporins play role in chloroplast osmoregulation and photosynthesis
SUMMARYPhotosynthetic oxygen evolution by photosystem II requires water supply into the chloroplast to reach the thylakoid lumen. A rapid water flow is also required into the chloroplast for optimal oxygen evolution and to overcome osmotic stress. The mechanisms governing water transport in chloroplasts are largely unexplored. Previous proteomics indicated the presence of three aquaporins from the tonoplast intrinsic protein (TIP) family, TIP1;1, TIP1;2 and TIP2;1, in chloroplast membranes of Arabidopsis thaliana. Here we revisited their location and studied their role in chloroplasts. Localization experiments indicated that TIP2;1 resides in the thylakoid, whereas TIP1;2 is present in both…
Reticulon-like proteins in Arabidopsis thaliana: structural organization and ER localization
International audience; Reticulons are proteins that have been found predominantly associated with the endoplasmic reticulum in yeast and mammalian cells. While their functions are still poorly understood, recent findings suggest that they participate in the shaping of the tubular endoplamic reticulum (ER). Although reticulon-like proteins have been identified in plants, very little is known about their cellular localization and functions. Here, we characterized the reticulon-like protein family of Arabidopsis thaliana. Three subfamilies can be distinguished on the basis of structural organization and sequence homology. We investigated the subcellular localization of two members of the larg…
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…
Distinct lytic vacuolar compartments are embedded inside the protein storage vacuole of dry and germinating Arabidopsis thaliana seeds.
International audience; Plant cell vacuoles are diverse and dynamic structures. In particular, during seed germination, the protein storage vacuoles are rapidly replaced by a central lytic vacuole enabling rapid elongation of embryo cells. In this study, we investigate the dynamic remodeling of vacuolar compartments during Arabidopsis seed germination using immunocytochemistry with antibodies against tonoplast intrinsic protein (TIP) isoforms as well as proteins involved in nutrient mobilization and vacuolar acidification. Our results confirm the existence of a lytic compartment embedded in the protein storage vacuole of dry seeds, decorated by γ-TIP, the vacuolar proton pumping pyrophospha…
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.
Tonoplast aquaporins facilitate lateral root emergence\ud
Pôle SPE IPM UB; International audience; Aquaporins (AQPs) are water channels allowing fast and passive diffusion of water across cell membranes. It was hypothesized that AQPs contribute to cell elongation processes by allowing water influx across the plasma membrane and the tonoplast to maintain adequate turgor pressure. Here, we report that, in Arabidopsis (Arabidopsis thaliana), the highly abundant tonoplast AQP isoforms AtTIP1;1, AtTIP1;2, and AtTIP2;1 facilitate the emergence of new lateral root primordia (LRPs). The number of lateral roots was strongly reduced in the triple tip mutant, whereas the single, double, and triple tip mutants showed no or minor reduction in growth of the mai…
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
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…