0000000000359751
AUTHOR
Parul Vatsa
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…
An early Ca2+ influx is a prerequisite to thaxtomin A-induced cell death in Arabidopsis thaliana cells
International audience; The pathogenicity of various Streptomyces scabies isolates involved in potato scab disease was correlated with the production of thaxtomin A. Since calcium is known as an essential second messenger associated with pathogen-induced plant responses and cell death, it was investigated whether thaxtomin A could induce a Ca 2+ influx related to cell death and to other putative plant responses using Arabidopsis thaliana suspension cells, which is a convenient model to study plant–microbe interactions. A. thaliana cells were treated with micromolar concentrations of thaxto-min A. Cell death was quantified and ion flux variations were analysed from electrophysiological measu…
Cytosolic calcium rises and related events in ergosterol-treated Nicotiana cells
International audience; The typical fungal membrane component ergosterol was previously shown to trigger defence responses and protect plants against pathogens. Most of the elicitors mobilize the second messenger calcium, to trigger plant defences. We checked the involvement of calcium in response to ergosterol using Nicotiana plumbaginifolia and Nicotiana tabacum cv Xanthi cells expressing apoaequorin in the cytosol. First, it was verified if ergosterol was efficient in these cells inducing modifications of proton fluxes and increased expression of defence-related genes. Then, it was shown that ergosterol induced a rapid and transient biphasic increase of free [Ca2þ]cyt which intensity dep…
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…
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…