0000000000014374
AUTHOR
Angela Garcia-brugger
Calcium signatures and signaling in cytosol and organelles of tobacco cells induced by plant defense elicitors
Calcium signatures induced by two elicitors of plant defense reactions, namely cryptogein and oligogalacturonides, were monitored at the subcellular level, using apoaequorin-transformed Nicotiana tabacum var Xanthi cells, in which the apoaequorin calcium sensor was targeted either to cytosol, mitochondria or chloroplasts. Our study showed that both elicitors induced specific Ca2+ signatures in each compartment, with the most striking difference relying on duration. Common properties also emerged from the analysis of Ca2+ signatures: both elicitors induced a biphasic cytosolic [Ca2+] elevation together with a single mitochondrial [Ca2+] elevation concomitant with the first cytosolic [Ca2+] p…
Involvement of the glutamate receptor AtGLR3.3 in plant defense signaling and resistance toHyaloperonospora arabidopsidis
Like their animal counterparts, plant glutamate receptor-like (GLR) homologs are intimately associated with Ca(2+) influx through plasma membrane and participate in various physiological processes. In pathogen-associated molecular patterns (PAMP)-/elicitor-mediated resistance, Ca(2+) fluxes are necessary for activating downstream signaling events related to plant defense. In this study, oligogalacturonides (OGs), which are endogenous elicitors derived from cell wall degradation, were used to investigate the role of Arabidopsis GLRs in defense signaling. Pharmacological investigations indicated that GLRs are partly involved in free cytosolic [Ca(2+)] ([Ca(2+)]cyt) variations, nitric oxide (N…
Bacterial rhamnolipids are novel MAMPs conferring resistance to Botrytis cinerea in grapevine
International audience; Rhamnolipids produced by the bacteria Pseudomonas aeruginosa are known as very efficient biosurfactant molecules. They are used for a wide range of industrial applications, especially in food, cosmetics and pharmaceutical formulations as well as in bioremediation of pollutants. In this paper, the role of rhamnolipids as novel molecules triggering defence responses and protection against the fungus Botrytis cinerea in grapevine is presented. The effect of rhamnolipids was assessed in grapevine using cell suspension cultures and vitro-plantlets. Ca2+ influx, mitogen-activated protein kinase activation and reactive oxygen species production form part of early signalling…
Early signaling events induced by elicitors of plant defenses
International audience; Plant pathogen attacks are perceived through pathogenissued compounds or plant-derived molecules that elicit defense reactions. Despite the large variety of elicitors, general schemes for cellular elicitor signaling leading to plant resistance can be drawn. In this article, we review early signaling events that happen after elicitor perception, including reversible protein phosphorylations, changes in the activities of plasma membrane proteins, variations in free calcium concentrations in cytosol and nucleus, and production of nitric oxide and active oxygen species. These events occur within the first minutes to a few hours after elicitor perception. One specific eli…
Involvement of putative glutamate receptors in plant defence signaling and NO production
International audience; Ionotropic glutamate receptors (iGluRs) are non-selective cation channels permeable to calcium, present in animals and plants. In mammals, glutamate is a well-known neurotransmitter and recently has been recognized as an immunomodulator. As animals and plants share common mechanisms that govern innate immunity with calcium playing a key role in plant defence activation, we have checked the involvement of putative iGluRs in plant defence signaling. Using tobacco cells, we first provide evidence supporting the activity of iGluRs as calcium channels and their involvement in NO production as reported in animals. Thereafter, iGluRs were shown to be activated in response t…
Caractérisation du mode d’action des rhamnolipides dans la défense des plantes et l’induction d’une résistance contre des agents phytopathogènes biotrophes et nécrotrophes
National audience; Les rhamnolipides (RL) sont des glycolipides amphiphiles produits par différentes bactéries notamment du genre Pseudomonas et Burkholderia. Les RL comprennent généralement une chaîne d’acides gras couplée à un ou plusieurs rhamnoses. Il sont impliqués dans la formation de biofilms, dans la mobilité bactérienne et constituent, pour certaines bactéries, des facteurs de virulence (Vatsa et al. 2010). Nous avons montré que les RL sont perçus en tant qu’éliciteurs par les cellules de vigne et que cette reconnaissance provoque un influx de Ca2+, l’activation de plusieurs MAPK (Mitogen-Activated Protein Kinase), la production de formes actives de l’oxygène ainsi que l’expression…