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The article informs that Coronavirus disease (COVID-19) is an emerging infectious contagious disease caused by a strain of coronavirus called SARS-CoV-2. It mentions that the symptoms are fever, cough and difficulty in breathing and, acute respiratory distress syndrome that can lead to death. It also informs about all the efforts made by different countries government and the Ministry of Internal Affairs for reducing the spread of COVID-19.

ABSTRACT Ozone (O3) is an air pollutant with an impact increasingly important in our industrialized world. It affects human health and productivity in various crops. We provide the evidences that treatment of Arabidopsis thaliana with O3 results in ascorbate-derived oxalic acid production. Using cultured cells of A. thaliana as a model, here we further showed that oxalic acid induces activation of anion channels that trigger depolarization of the cell, increase in cytosolic Ca2+ concentration, generation of reactive oxygen species and cell death. We confirmed that O3 reacts with ascorbate in the culture, thus resulting in production of oxalic acid and this could be part of the O3-induced signalling pathways that trigger programmed cell death. [ABSTRACT FROM AUTHOR]

Background: 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. Principal Findings: By exposing cells to a strong pulse of ozonized air, an acute cell death was observed in suspension cells of Arabidopsis thaliana used as a model. We demonstrated that O3 treatment induced the activation of a plasma membrane anion channel that is an early prerequisite of O3-induced cell death in A. thaliana. Our data further suggest interplay of anion channel activation with well known plant responses to O3, Ca2+ influx and NADPH-oxidase generated reactive oxygen species (ROS) in mediating the oxidative cell death. This interplay might be fuelled by several mechanisms in addition to the direct ROS generation by O3; namely, H2O2 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. Significance: Collectively, our data indicate that anion efflux is an early key component of morphological and biochemical events leading to O3-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. [ABSTRACT FROM AUTHOR]

The authors would like to remove the scientific consortium "Camille Nous" from the author list and the Author Contributions section in the published paper [[1]], as suggested by the Editorial Office. To recognize the consortium's contribution, the authors claimed a double affiliation of two of the authors to the Cogitamus laboratory [[2]]. Early Cellular Responses Induced by Sedimentary Calcite-Processed Particles in Bright Yellow 2 Tobacco Cultured Cells. [Extracted from the article]

Calcite processed particles (CaPPs, Megagreen®) elaborated from sedimentary limestone rock, and finned by tribomecanic process were found to increase photosynthetic CO2 fixation grapevines and stimulate growth of various cultured plants. Due to their processing, the CaPPs present a jagged shape with some invaginations below the micrometer size. We hypothesised that CaPPs could have a nanoparticle (NP)-like effects on plants. Our data show that CaPPs spontaneously induced reactive oxygen species (ROS) in liquid medium. These ROS could in turn induce well-known cellular events such as increase in cytosolic Ca2+, biotic ROS generation and activation of anion channels indicating that these CaPPs could activate various signalling pathways in a NP-like manner. [ABSTRACT FROM AUTHOR]

Plant growth promoting rhizobacteria (PGPR) are beneficial bacterial that colonize plant roots and enhance plant growth by a wide variety of mechanisms. Seven isolates of bacteria were successfully isolated and phenotypically, biochemically, physiological and molecular characterized. Subsequently to investigate the effect of PGPR isolates on the growth of carob tree, a pot culture experiement was conducted as Centre for Innovation and Technology Transfer (CITT), Meknes, Morocco. All the isolates were gram negative, rods, motile, able to grow on YDC medium and citrate simmons positive, degrade glucose, fructose and mannitol, capable of hydrolyzing esculin and starch. All strains are able to produce (74-150µgml-1) of indole acetic acid, nitrogen fixatin and all isolate are unable to produce ammonia, chitinase and cellulase, the strains 2018-3, 2018-4 and 2018-5 showed protease activity. The pecentage of solibilization of phosphate varied between 15% to 45%, the maximum phosphate solubilization was identified by stain 2018-4. Sequencing of 16SrRNA genes led to the identification of two family of bacteria: Bacillaceae and Pseudomonadaceae. The species of bacteria are: Bacillus thuringiensis, two of Bacillus flexus, two of Pseudomonas gessardii, Bacillus cereus and Bacillus thaonhiensis. The analysis the result showed that the highest vegetative growth was obtained from stain 2018-4 such as plant height (13.6cm), root length (13.65cm), fresh weight of the aerial part (1.09g) and fresh weight of the root part (0.42g) in comparison to untreated plant. [ABSTRACT FROM AUTHOR]

Thaxtomin A (TXT) is a phytotoxin produced by all plant-pathogenic Streptomyces scabies involved in the potato scab disease. Their pathogenicity was previously correlated with the production of TXT. Calcium is known to be an essential second messenger associated with pathogen-induced plant responses and cell death. We have effectively shown that in Arabidopsis thaliana cell suspensions, TXT induces an early short lived Ca(2+) influx which is involved in the cell death process and other TXT-induced responses. We extended our study to Nicotiana tabacum BY2 by monitoring cell death and changes in cytosolic calcium concentration on cells expressing the apoaequorine Ca(2+) reporter protein to compare the responses to TXT of the two model plants, tobacco and A. thaliana. Our investigations show that cell death in BY2 appeared to be dose dependent with a lag of sensitivity comparing to A. thaliana. Moreover, pathway leading to cell death in BY2 does not involve calcium signaling. Our results suggest that different pathways are engaged in A. thaliana and N. tabacum BY2 to achieve the same response to TXT.

Oxalic acid is thought to be a key factor of the early pathogenic stage in a wide range of necrotrophic fungi. We have recently published that oxalic acid induces Programmed Cell Death (PCD) in Arabidopsis thaliana cells. This cell death results from an early anionic efflux which is a prerequisite for the synthesis of ethylene and the PCD. Complementary experiments have been carried out by using seedlings of A. thaliana. The effects of millimolar concentrations of oxalic acid were analysed on A. thaliana seedlings. A treatment with a 3 mM oxalic acid solution does not alter the development of the plants but induces the transcription of defence related genes which are anion channel dependant. Moreover, our results suggest that a pre-treatment of the seedlings with oxalic acid is able to confer the resistance of A. thaliana against Sclerotium rolfsii. Regarding our results, we suggest that oxalic acid plays two distinct roles, depending on the concentration: a high concentration of oxalic acid induces a large PCD and then contribute to the progression of the fungi. However, at low concentration it is able to induce the establishment of a resistance of the plant against the fungi.

In plant/parasitic plant interaction, little is known about the host plant response before the establishment of the parasite within the host. In the present work, we focused on host responses to parasitic plant, O. ramosa in the early stage of infection. We used a co-culture system of A. thaliana suspension cells and O. ramosa germinated-seeds to avoid parasite attachment. We showed that O. ramosa induced H(2)O(2) generation and camalexin synthesis by A. thaliana followed by a drastic increase in cell death. We further demonstrated that a heat sensitive diffusible signal is responsible for this cell death. These data indicate that recognition of O. ramosa occurs before the attachment of the parasite and initiates plant defence responses.