Enhanced elevations of hypo-osmotic shock-induced cytosolic and nucleic calcium concentrations in tobacco cells by pretreatment with dimethyl sulfoxide

International audienc

Green thermoelectrics: Observation and analysis of plant thermoelectric response

Plants are sensitive to thermal and electrical effects; yet the coupling of both, known as thermoelectricity, and its quantitative measurement in vegetal systems never were reported. We recorded the thermoelectric response of bean sprouts under various thermal conditions and stress. The obtained experimental data unambiguously demonstrate that a temperature difference between the roots and the leaves of a bean sprout induces a thermoelectric voltage between these two points. Basing our analysis of the data on the force-flux formalism of linear response theory, we found that the strength of the vegetal equivalent to the thermoelectric coupling is one order of magnitude larger than that in the best thermoelectric materials. Experimental data also show the importance of the thermal stress variation rate in the plant's electrophysiological response. Therefore, thermoelectric effects are sufficiently important to partake in the complex and intertwined processes of energy and matter transport within plants

Arabidopsis thaliana cells: a model to evaluate the virulence of Pectobacterium carotovorum.

Pectobacterium carotovorum are economically important plant pathogens that cause plant soft rot. These enterobacteria display high diversity world-wide. Their pathogenesis depends on production and secretion of virulence factors such as plant cell wall-degrading enzymes, type III effectors, a necrosis-inducing protein, and a secreted virulence factor from Xanthomonas spp., which are tightly regulated by quorum sensing. Pectobacterium carotovorum also present pathogen-associated molecular patterns that could participate in their pathogenicity. In this study, by using suspension cells of Arabidopsis thaliana, we correlate plant cell death and pectate lyase activities during coinfection with different P. carotovorum strains. When comparing soft rot symptoms induced on potato slices with pectate lyase activities and plant cell death observed during coculture with Arabidopsis thaliana cells, the order of strain virulence was found to be the same. Therefore, Arabidopsis thaliana cells could be an alternative tool to evaluate rapidly and efficiently the virulence of different P. carotovorum strains

Establishment of a cell suspension culture of the halophyte Cakile maritima

Cakile maritima is a member of the Brassicaceae family also known as sea rocket. It is an annual succulent halophyte frequent in coastal dune vegetation in Mediterranean regions and Atlantic coasts from North Africa to the north of Europe. This halophyte presents a complex survival strategy at high salinity and its seeds contain up to 40% of an oil which could be suitable for biofuel production and other industrial applications. However, data concerning the cellular mechanisms allowing this plant to resist salinity are still lacking. Cell suspension cultures offer an in vitro system convenient for cell biology studies and biotechnological methods are still not developed for this putative crop. The present paper reports initiation of C. maritima cell suspension cultures from callus obtained from aerial parts of seedlings. The establishment of a suspension culture which preserves its salt resistance provides an opportunity to gain insights into C. maritima biology

パリ第7大学と北九州市立大学との共同でのソルボンヌ大学由来の植物学史研究資料の調査、保存および再評価

This article describes the recent collaboration between Japanese and French teams aiming at the survey on the corpus of the history of botanical sciences in Paris, based on the literatures originated from the libraries of Université de Paris, one of the world oldest universities (well known as Sorbonne). Two teams attempted to fully re-collect and preserve the Sorbonne-derived botanical literatures at Université Paris Diderot through successive surveys in recent 2 years. As a result, many of classical books, doctoral theses and journals (dated between 1815-1970) were re-collected and registered as the open-access sources for future analyses

Use of liquefied cold temperature dimethyl ether for extraction of pigments from fresh vegetable tissues

Dimethyl ether (DME) is known as a useful precursor to other organic compounds and is a promising alternative fuel without issues of toxicity, production, infrastructure, and transportation as is the case with various other fuels. Recently, DME has attracted the attention of scientists and engineers since it behaves as a subcritical solvent or a low-temperature solvent applicable for the extraction of organic molecules from bio-materials. This paper presents the extraction of chlorophylls and carotenoids from green peel and yellow cortex of Japanese squash, spinach leaves and carrot roots using low-temperature liquefied DME. Spectroscopic and fluorescence analyses of the extracted pigments revealed that chlorophylls were successfully extracted by liquefied DME from green materials (squash peel and spinach leaves). HPLC analysis further confirmed that chlorophylls extracted include both chlorophylls a and b. By using liquefied DME, carotenoids were extracted from all vegetable samples examined. The performance of DME as a novel pigment extracting agent is confirmed in this work and its use as a “green” solvent, as opposed to conventional solvents, for the preparation and extraction of various plant pigments is highly encouraged from an environmental point of view

Early events induced by the toxin deoxynivalenol lead to programmed cell death in Nicotiana tabacum cells

Deoxynivalenol (DON) is a mycotoxin affecting animals and plants. This toxin synthesized by Fusarium culmorum and Fusarium graminearum is currently believed to play a decisive role in the fungal phytopathogenesis as a virulence factor. Using cultured cells of Nicotiana tabacum BY2, we showed that DON-induced programmed cell death (PCD) could require transcription and translation processes, in contrast to what was observed in animal cells. DON could induce different cross-linked pathways involving (i) reactive oxygen species (ROS) generation linked, at least partly, to a mitochondrial dysfunction and a transcriptional down-regulation of the alternative oxidase (Aox1) gene and (ii) regulation of ion channel activities participating in cell shrinkage, to achieve PCD

Increased Anion Channel Activity Is an Unavoidable Event in Ozone-Induced Programmed Cell Death

Ozone is a major secondary air pollutant often reaching high concentrations in urban areas under strong daylight, high temperature and stagnant high-pressure systems. Ozone in the troposphere is a pollutant that is harmful to the plant. generation by salicylic and abscisic acids. Anion channel activation was also shown to promote the accumulation of transcripts encoding vacuolar processing enzymes, a family of proteases previously reported to contribute to the disruption of vacuole integrity observed during programmed cell death.-induced programmed cell death. Because ion channels and more specifically anion channels assume a crucial position in cells, an understanding about the underlying role(s) for ion channels in the signalling pathway leading to programmed cell death is a subject that warrants future investigation

Table ronde sur l'intelligence des arbres

info:eu-repo/semantics/nonPublishe

Crosstalk between intracellular and extracellular salicylic acid signaling events leading to long-distance spread of signals

International audienceIt is well recognized that salicylic acid (SA) acts as a natural signaling molecule involved in both local and systemic plant defense responses upon attacks by pathogens. Recently, cellular SA receptors and a number of SA-related phloem-mobile signals were identified. Here, we compare the old and up-to-date concepts of plant defense signaling events involving SA. Finally, the crosstalk between intracellular and extracellular SA signaling events leading to long-distance spread of signals was outlined by focusing on the modes of both the short-and long-distance signaling events involving the actions of SA. For the above purpose, two distinct conceptual models for local SA perception and signaling mechanisms in the intracellular and extracellular paths (referred to as models i and ii, respectively) were proposed. In addition to two local SA perception models, we propose that the long-distance SA action could be attributed to three different modes, namely, (iii) local increase in SA followed by transport of SA and SA intermediates, (iv) systemic propagation of SA-derived signals with both chemical and electrical natures without direct movement of SA, and (v) integrated crosstalk allowing alternately repeated secondary signal propagation and biosynthesis of SA and/or conversion of inert SA intermediates to free SA finally contributing to the systemic spread of SA-derived signals. We review here that the long-distance SA signaling events (models iii-v), inevitably involve the mechanisms described in the local signaling models (models i and ii) as the key pieces of the crosstalk