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RESEARCH PRODUCT

Réponses des cellules de Nicotiana tabacum à des molécules microbiennes : évènements de signalisation précoce, influence de la dynamique membranaire et flux de sucres

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Responses of Nicotiana tabacum cells to microbial molecule treatments: early signaling events,influence of membrane dynamics, and sugar fluxesIn their natural environment plants are in close interaction with beneficial, neutral, or pathogenicmicrobes, which are highly dependent on carbon resources exuded by plant roots. Sugar transport, which isa key process of plant physiology, is essential to support the fate of plant-microbe interactions. Duringevolution, plants have acquired the ability to perceive microbial molecules, initiating specific signaltransduction cascades and leading to adapted response for microbe lifestyles (avirulent, virulent, or benefic).Plant survival will depend on the nature of the induced mechanisms. My PhD work, carried out on asimplified experimental system, contributes to the understanding of mechanisms underlying the determinismof plant-microbe interactions. We used Nicotiana tabacum cells in suspension exposed to microbialmolecules derived from mutualistic or avirulent microbes. Using such a simplified system, we analyzedelements of the early signaling cascade and sugar fluxes. We have shown that CO4, which is originating fromAMF, initiate early signaling components (rbohD-dependent H2O2, cytosolic Ca2+, MAPK activation) ascryptogein, a defense elicitor, but with distinct profile and amplitude. Those two molecules (CO4 andcryptogein) are responsible of different effects on sugar fluxes and the expression of the underlying sugartransporter genes. In addition, we presented an impact of the alteration of clathrin-mediated process on earlysignaling events triggered by cryptogein, as well as inward sugar fluxes and expression of sugar transportergenes. Finally, in silico analyses of sugar transporter interactome in Arabidopsis thaliana has provided somepossible regulation mechanisms through the identification of new candidate proteins involved in sugartransporter regulation. These information open new perspectives towards a better understanding of thecellular and molecular mechanisms involved in plant-microbe interactions.