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Previous studies on RNase R have highlighted significant effects of this ribonuclease in several processes of Streptococcus pneumoniae biology. In this work we show that elimination of RNase R results in overexpression of most of genes encoding the components of type II fatty acid biosynthesis (FASII) cluster. We demonstrate that RNase R is implicated in the turnover of most of transcripts from this pathway, affecting the outcome of the whole FASII cluster, and ultimately leading to changes in the membrane fatty acid composition. Our results show that the membrane of the deleted strain contains higher proportion of unsaturated and long-chained fatty acids than the membrane of the wild type strain. These alterations render the RNase R mutant more prone to membrane lipid peroxidation and are likely the reason for the increased sensitivity of this strain to detergent lysis and to the action of the bacteriocin nisin. Reprogramming of membrane fluidity is an adaptative cell response crucial for bacterial survival in constantly changing environmental conditions. The data presented here is suggestive of a role for RNase R in the composition of S. pneumoniae membrane, with strong impact on pneumococci adaptation to different stress situations.
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The widespread use of pesticides in agriculture remains a matter of major concern, prompting a critical need for alternative and sustainable practices. To address this, the use of lipid-derived molecules as elicitors to induce defence responses in grapevine plants was accessed. A Plasmopara viticola fatty acid (FA), eicosapentaenoic acid (EPA) naturally present in oomycetes, but absent in plants, was applied by foliar spraying to the leaves of the susceptible grapevine cultivar (Vitis vinifera cv. Trincadeira), while a host lipid derived phytohormone, jasmonic acid (JA) was used as a molecule known to trigger host defence. Their potential as defence triggers was assessed by analysing the expression of a set of genes related to grapevine defence and evaluating the FA modulation upon elicitation. JA prompted grapevine immunity, altering lipid metabolism and up-regulating the expression of several defence genes. EPA also induced a myriad of responses to the levels typically observed in tolerant plants. Its application activated the transcription of defence gene's regulators, pathogen-related genes and genes involved in phytoalexins biosynthesis. Moreover, EPA application resulted in the alteration of the leaf FA profile, likely by impacting biosynthetic, unsaturation and turnover processes. Although both molecules were able to trigger grapevine defence mechanisms, EPA induced a more robust and prolonged response. This finding establishes EPA as a promising elicitor for an effectively managing grapevine downy mildew diseases.
Sujet(s)
Cyclopentanes , Acide eicosapentanoïque , Oomycetes , Oxylipines , Vitis , Vitis/microbiologie , Vitis/métabolisme , Vitis/génétique , Vitis/immunologie , Vitis/effets des médicaments et des substances chimiques , Acide eicosapentanoïque/métabolisme , Oomycetes/physiologie , Oxylipines/métabolisme , Cyclopentanes/métabolisme , Régulation de l'expression des gènes végétaux/effets des médicaments et des substances chimiques , Maladies des plantes/microbiologie , Maladies des plantes/immunologie , Immunité des plantes/effets des médicaments et des substances chimiques , Feuilles de plante/métabolisme , Feuilles de plante/effets des médicaments et des substances chimiques , Feuilles de plante/immunologie , Feuilles de plante/microbiologieRÉSUMÉ
Introduction: Artemisinin is a secondary metabolite well-known for its use in the treatment of malaria. It also displays other antimicrobial activities which further increase its interest. At present, Artemisia annua is the sole commercial source of the substance, and its production is limited, leading to a global deficit in supply. Furthermore, the cultivation of A. annua is being threatened by climate change. Specifically, drought stress is a major concern for plant development and productivity, but, on the other hand, moderate stress levels can elicit the production of secondary metabolites, with a putative synergistic interaction with elicitors such as chitosan oligosaccharides (COS). Therefore, the development of strategies to increase yield has prompted much interest. With this aim, the effects on artemisinin production under drought stress and treatment with COS, as well as physiological changes in A. annua plants are presented in this study. Methods: Plants were separated into two groups, well-watered (WW) and drought-stressed (DS) plants, and in each group, four concentrations of COS were applied (0, 50,100 and 200 mgâ¢L-1). Afterwards, water stress was imposed by withholding irrigation for 9 days. Results: Therefore, when A. annua was well watered, COS did not improve plant growth, and the upregulation of antioxidant enzymes hindered the production of artemisinin. On the other hand, during drought stress, COS treatment did not alleviate the decline in growth at any concentration tested. However, higher doses improved the water status since leaf water potential (YL) improved by 50.64% and relative water content (RWC) by 33.84% compared to DS plants without COS treatment. Moreover, the combination of COS and drought stress caused damage to the plant's antioxidant enzyme defence, particularly APX and GR, and reduced the amount of phenols and flavonoids. This resulted in increased ROS production and enhanced artemisinin content by 34.40% in DS plants treated with 200 mgâ¢L-1 COS, compared to control plants. Conclusion: These findings underscore the critical role of ROS in artemisinin biosynthesis and suggest that COS treatment may boost artemisinin yield in crop production, even under drought conditions.
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Superior vena cava syndrome (SVCS) is caused by any obstruction to the superior vena cava (SVC); the most common causes are malignancy and extrinsic compression. The use of medical devices, such as central venous catheters, poses an important risk factor, as they cause changes in the blood flow and in the vessel wall. This report describes a case of a 70-year-old male with an implantable central venous port, due to previous neoplastic disease, as the cause of the SVCS. Authors advise that the placement of medical devices ought to be carefully accessed and constantly revised to be removed when no longer needed to prevent avoidable complications.
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The apoplast is the plant compartment present between the plasma membrane and the cuticle, comprised of the cell wall and the extracellular spaces where the "secretomes" are released and where the apoplastic fluid circulates. Within the many functions attributed to this compartment, its role in plant-pathogen interactions is irrefutable. It is the major point where plant and pathogen secretomes come in contact and several plant and pathogenic secreted proteins and small molecules present in this compartment are already cataloged in the literature. In plant-pathogen interactions, fatty acids and lipid molecules were shown to play a crucial role in the activation of plant immunity; however, the lipid composition of the apoplast is still a black box. Most of the studies performed to understand apoplast dynamics have used proteomic-based techniques; however, knowledge about apoplastic proteins involved in lipid metabolism and transport is still severely limited. In grapevine, only three studies have been published so far focusing on the characterization of this compartment and only one of them deals with grapevine-pathogen interaction. Here we refer to our recently established method for grapevine leaves' apoplastic fluid isolation and describe a direct methylation protocol for the analysis of apoplastic fluid fatty acids. We also point out a novel intracellular marker that may be used to assess apoplastic fluid purity.
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Acides gras , Vitis , Acides gras/métabolisme , Protéomique , Feuilles de plante/métabolisme , Espace extracellulaire/métabolisme , Protéines végétales/métabolisme , Vitis/métabolisme , Maladies des plantesRÉSUMÉ
The anticipated rise in the length, frequency, and intensity of heatwaves (HW) in the Mediterranean region poses a danger to the crops, as these brief but high-intensity thermal stress events halt plant productivity. This arises the need to develop new eco-friendly sustainable strategies to overcome food demand. Halophytes such as Salicornia ramosissima appear as cash crop candidates, alongside with new biofertilization approaches using Plant Growth Promoting Bacteria (PGPB). In the present work, S. ramosissima plants exposed to heatwave (HW) treatments with and without marine PGPB inoculation is studied to evaluate the physiological responses behind eventual thermal adaptation conditions. Plants exposed to HW inoculated with ACC deaminase and IAA-producing PGPB showed a 50% reduction in the photochemical energy dissipation, when compared to their non-inoculated counterparts, indicating higher light-use efficiency. The observed concomitant increase (76-234%) in several pigments indicates improved inoculated HW-exposed individuals' light harvesting and photoprotection under stressful conditions. This reduction of the physiological stress levels in inoculated plants was also evident by the significant reduction of several antioxidant enzymes as well as of membrane lipid peroxidation products. Additionally, improved membrane stability could also be observed, through the regulation of fatty acid unsaturation levels, decreasing the excessive fluidity imposed by HW treatment. All these improved physiological traits associated with specific PGP traits highlight a key potential of the use of these PGPB consortiums as biofertilizers for S. ramosissima cash crop production in the Mediterranean, where increasing frequency in HW-events is a major drawback to plant production, even to warm-climate plants.
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Chenopodiaceae , Rhizosphère , Bactéries , Développement des plantes , AntioxydantsRÉSUMÉ
Amid climate change, heatwave events are expected to increase in frequency and severity. As a result, yield losses in viticulture due to heatwave stress have increased over the years. As one of the most important crops in the world, an eco-friendly stress mitigation strategy is greatly needed. The present work aims to evaluate the physiological fitness improvement by two marine plant growth-promoting rhizobacteria consortia in Vitis vinifera cv. Antão Vaz under heatwave conditions. To assess the potential biophysical and biochemical thermal stress feedback amelioration, photochemical traits, pigment and fatty acid profiles, and osmotic and oxidative stress biomarkers were analysed. Bioaugmented grapevines exposed to heatwave stress presented a significantly enhanced photoprotection capability and higher thermo-stability, exhibiting a significantly lower dissipation energy flux than the non-inoculated plants. Additionally, one of the rhizobacterial consortia tested improved light-harvesting capabilities by increasing reaction centre availability and preserving photosynthetic efficiency. Rhizobacteria inoculation expressed an osmoprotectant promotion, revealed by the lower osmolyte concentration while maintaining leaf turgidity. Improved antioxidant mechanisms and membrane stability resulted in lowered lipid peroxidation product formation when compared to non-inoculated plants. Although the consortia were found to differ significantly in their effectiveness, these findings demonstrate that bioaugmentation induced significant heatwave stress tolerance and mitigation. This study revealed the promising usage of marine PGPR consortia to promote plant fitness and minimize heatwave impacts in grapevines.
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In this work, we studied the combined effect of increased temperature and atmospheric CO2, salt and drought stress, and inoculation with plant-growth-promoting rhizobacteria (PGPR) on the growth and some nutritional parameters of the edible halophyte Salicornia ramosissima. We found that the increase in temperature and atmospheric CO2, combined with salt and drought stresses, led to important changes in S. ramosissima fatty acids (FA), phenols, and oxalate contents, which are compounds of great importance for human health. Our results suggest that the S. ramosissima lipid profile will change in a future climate change scenario, and that levels of oxalate and phenolic compounds may change in response to salt and drought stress. The effect of inoculation with PGPR depended on the strains used. Some strains induced the accumulation of phenols in S. ramosissima leaves at higher temperature and CO2 while not altering FA profile but also led to an accumulation of oxalate under salt stress. In a climate change scenario, a combination of stressors (temperature, salinity, drought) and environmental conditions (atmospheric CO2, PGPR) will lead to important changes in the nutritional profiles of edible plants. These results may open new perspectives for the nutritional and economical valorization of S. ramosissima.
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Several millions of individuals are estimated to develop post-acute sequelae SARS-CoV-2 condition (PASC) that persists for months after infection. Here we evaluate the immune response in convalescent individuals with PASC compared to convalescent asymptomatic and uninfected participants, six months following their COVID-19 diagnosis. Both convalescent asymptomatic and PASC cases are characterised by higher CD8+ T cell percentages, however, the proportion of blood CD8+ T cells expressing the mucosal homing receptor ß7 is low in PASC patients. CD8 T cells show increased expression of PD-1, perforin and granzyme B in PASC, and the plasma levels of type I and type III (mucosal) interferons are elevated. The humoral response is characterized by higher levels of IgA against the N and S viral proteins, particularly in those individuals who had severe acute disease. Our results also show that consistently elevated levels of IL-6, IL-8/CXCL8 and IP-10/CXCL10 during acute disease increase the risk to develop PASC. In summary, our study indicates that PASC is defined by persisting immunological dysfunction as late as six months following SARS-CoV-2 infection, including alterations in mucosal immune parameters, redistribution of mucosal CD8+ß7Integrin+ T cells and IgA, indicative of potential viral persistence and mucosal involvement in the etiopathology of PASC.
Sujet(s)
COVID-19 , SARS-CoV-2 , Humains , Maladie aigüe , Lymphocytes T CD8+ , Dépistage de la COVID-19 , Évolution de la maladie , Immunoglobuline ARÉSUMÉ
Vitis vinifera L. is highly susceptible to the biotrophic pathogen Plasmopara viticola. To control the downy mildew disease, several phytochemicals are applied every season. Recent European Union requirements to reduce the use of chemicals in viticulture have made it crucial to use alternative and more sustainable approaches to control this disease. Our previous studies pinpoint the role of fatty acids and lipid signalling in the establishment of an incompatible interaction between grapevine and P. viticola. To further understand the mechanisms behind lipid involvement in an effective defence response we have analysed the expression of several genes related to lipid metabolism in three grapevine genotypes: Chardonnay (susceptible); Regent (tolerant), harbouring an Rpv3-1 resistance loci; and Sauvignac (resistant) that harbours a pyramid of Rpv12 and Rpv3-1 resistance loci. A highly aggressive P. viticola isolate was used (NW-10/16). Moreover, we have characterised the grapevine phospholipases C and D gene families and monitored fatty acid modulation during infection. Our results indicate that both susceptible and resistant grapevine hosts did not present wide fatty acid or gene expression modulation. The modulation of genes associated with lipid signalling and fatty acids seems to be specific to Regent, which raises the hypothesis of being specifically linked to the Rpv3 loci. In Sauvignac, the Rpv12 may be dominant concerning the defence response, and, thus, this genotype may present the activation of other pathways rather than lipid signalling.
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Oomycetes , Peronospora , Humains , Résistance à la maladie/génétique , Oomycetes/physiologie , Acides gras , LipidesRÉSUMÉ
The increased use of antidepressants, along with their increased occurrence in aquatic environments, is of concern for marine organisms. Although these pharmaceutical compounds have been shown to negatively affect marine diatoms, their mode of action in these non-target, single-cell phototrophic organisms is yet unknown. Using a Fourier-transform ion cyclotron-resonance mass spectrometer (FT-ICR-MS) we evaluated the effects of fluoxetine in the metabolomics of the model diatom Phaeodactylum tricornutum, as well as the potential use of the identified metabolites as exposure biomarkers. Diatom growth was severely impaired after fluoxetine exposure, particularly in the highest dose tested, along with a down-regulation of photosynthetic and carbohydrate metabolisms. Notably, several mechanisms that are normally down-regulated by fluoxetine in mammal organisms were also down-regulated in diatoms (e.g., glycerolipid metabolism, phosphatidylinositol signalling pathway, vitamin metabolism, terpenoid backbone biosynthesis and serotonin remobilization metabolism). Additionally, the present work also identified a set of potential biomarkers of fluoxetine exposure that were up-regulated with increasing fluoxetine exposure concentration and are of high metabolic significance following the disclosed mode of action, reinforcing the use of metabolomics approaches in ecotoxicology.
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Sodium Dodecyl Sulfate (SDS) is an anionic surfactant, extensively used in detergents, household and personal care products, as well as in industrial processes. The present study aimed to disclose the potential toxicological effects of SDS exposure under environmentally relevant concentrations (0, 0.1, 1, 3, and 10 mg L-1) on the physiology and biochemistry (photosynthesis, pigment, and lipid composition, antioxidative systems, and energy balance) of two marine autotrophs: the diatom Phaeodactylum tricornutum and the macroalgae Ulva lactuca. A growth rate (GR) reduction in P. tricornutum was observed with a classic dose-response effect towards the highest applied concentration, while a GR increase occurred in U. lactuca. Regarding photochemistry, the decrease in the fluorescence of the OJIP curves and laser-induced fluorescence allowed a better separation between SDS treatments in U. lactuca compared with P. tricornutum. Although all pigments significantly decreased in U. lactuca at the highest concentrations (except for antheraxanthin), no significant variations occurred in P. tricornutum. On the other hand, changes in fatty acid content were observed in P. tricornutum but not in U. lactuca. In terms of classical biomarker assessment, a dose-effect relationship of individual biomarkers versus SDS dose applied; U. lactuca displayed a higher number of biomarker candidates, including those in distinct metabolic pathways, increasing its usefulness for ecotoxicological applications. By evaluating the potential application of optical and biochemical traits, it was evident that the fatty acid profiles of the different exposure groups are excellent candidates in P. tricornutum, concomitant with the characteristics of this anionic surfactant. On the other hand, the results presented by laser-induced fluorescence and some parameters of PAM fluorometry in U. lactuca may be an advantage in the field, offering non-invasive, fast, easy-to-use, high-throughput screening techniques as excellent tools for ecotoxicology assessment.
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The use of glyphosate-based herbicides (GBHs) worldwide has increased exponentially over the last two decades increasing the environmental risk to marine and coastal habitats. The present study investigated the effects of GBHs at environmentally relevant concentrations (0, 10, 50, 100, 250, and 500 µg·L-1) on the physiology and biochemistry (photosynthesis, pigment, and lipid composition, antioxidative systems and energy balance) of Ulva lactuca, a cosmopolitan marine macroalgae species. Although GBHs cause deleterious effects such as the inhibition of photosynthetic activity, particularly at 250 µg·L-1, due to the impairment of the electron transport in the chloroplasts, these changes are almost completely reverted at the highest concentration (500 µg·L-1). This could be related to the induction of tolerance mechanisms at a certain threshold or tipping point. While no changes occurred in the energy balance, an increase in the pigment antheraxanthin is observed jointly with an increase in ascorbate peroxidase activity. These mechanisms might have contributed to protecting thylakoids against excess radiation and the increase in reactive oxygen species, associated with stress conditions, as no increase in lipid peroxidation products was observed. Furthermore, changes in the fatty acids profile, usually attributed to the induction of plant stress response mechanisms, demonstrated the high resilience of this macroalgae. Notably, the application of bio-optical tools in ecotoxicology, such as pulse amplitude modulated (PAM) fluorometry and laser-induced fluorescence (LIF), allowed separation of the control samples and those treated by GBHs in different concentrations with a high degree of accuracy, with PAM more accurate in identifying the different treatments.
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The present-day COVID-19 pandemic has led to the increasing daily use of antimicrobials worldwide. Triclosan is a manmade disinfectant chemical used in several consumer healthcare products, and thus frequently detected in surface waters. In the present work, we aimed to evaluate the effect of triclosan on diatom cell photophysiology, fatty acid profiles, and oxidative stress biomarkers, using the diatom Phaeodactylum tricornutum as a model organism. Several photochemical effects were observed, such as the lower ability of the photosystems to efficiently trap light energy. A severe depletion of fucoxanthin under triclosan application was also evident, pointing to potential use of carotenoid as reactive oxygen species scavengers. It was also observed an evident favouring of the peroxidase activity to detriment of the SOD activity, indicating that superoxide anion is not efficiently metabolized. High triclosan exposure induced high cellular energy allocation, directly linked with an increase in the energy assigned to vital functions, enabling cells to maintain the growth rates upon triclosan exposure. Oxidative stress traits were found to be the most efficient biomarkers as promising tools for triclosan ecotoxicological assessments. Overall, the increasing use of triclosan will lead to significant effects on the diatom photochemical and oxidative stress levels, compromising key roles of diatoms in the marine system.
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Estuaries have long been preferred areas of human settlement, where multiple anthropogenic activities take place, which have contributed to a significant decrease in environmental quality of these ecosystems. Accordingly, environmental monitoring and management have long relied on the development of tools that summarize and simplify complex information and provide direct interpretation of quality status. Here, the fatty acid profiles of three abundant estuarine species, namely Hediste diversicolor, Carcinus maenas and Pomatoschistus microps, were used to develop and validate a multimetric index, based on the Euclidean dissimilarities of profiles between sites, in response to contamination gradient in a large urban estuary. Spatial differences were generally related to unsaturated fatty acids (mono- and polyunsaturated, of the n-3 and n-6 series) in all species, albeit more pronounced in P. microps. Multivariate models returned high classification accuracies for the three sampled sites, varying from 73.3% in the invertebrate species to 100.0% in the fish species. Results show the applicability of the developed FA-based index, particularly due to the easy of communication, for managers and the public alike, but also highlight the need for prior validation on species suitability or sensitivity to depict environmental contamination.
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Écosystème , Polluants chimiques de l'eau , Animaux , Surveillance de l'environnement/méthodes , Estuaires , Acides gras , Polluants chimiques de l'eau/analyseRÉSUMÉ
Coastal seagrass meadows provide a variety of essential ecological and economic services, including nursery grounds, sediment stabilization, nutrient cycling, coastal protection, and blue carbon sequestration. However, these ecosystems are highly threatened by ongoing climatic change. This study was aimed to understand how the dwarf eelgrass Zostera noltii leaf lipid landscapes are altered under predicted ocean warming (+4 °C) and hypercapnic (ΔpH 0.4) conditions. Warming and hypercapnic conditions were found to induce a severe reduction in the leaf total fatty acid, though the combined treatment substantially alleviated this depletion. The lipid discrimination revealed a significant increase in the relative monogalactosyldiacylglycerol (MGDG) content in both hypercapnic and warming conditions, allied to plastidial membrane stabilization mechanisms. Hypercapnia also promoted enhanced phosphatidylglycerol (PG) leaf contents, a mechanism often associated with thylakoid reinvigoration. In addition to changing the proportion of storage, galacto- and phospholipids, the tested treatments also impacted the FA composition of all lipid classes, with warming exposure leading to decreases in polyunsaturated fatty acids (PUFAs); however, the combination of both stress conditions alleviated this effect. The observed galactolipid and phospholipid PUFA decreases are compatible with a homeoviscous adaptation, allowing for the maintenance of membrane stability by counteracting excessive membrane fluidity. Neutral lipid contents were substantially increased under warming conditions, especially in C18 fatty acids (C18), impairing their use as substrates for fatty acylated derivatives essential for maintaining the osmotic balance of cells. An analysis of the phospholipid and galactolipid fatty acid profiles as a whole revealed a higher degree of discrimination, highlighting the higher impact of warming and the proposed stress alleviation effect induced by increased water-dissolved CO2 availability. Still, it is essential to remember that the pace at which the ocean is warming can overcome the ameliorative capacity induced by higher CO2 availability, leaving seagrasses under severe heat stress beyond their lipid remodeling capacity.
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The introduction of waste containing heavy metals into the marine environment has been increasing for the past few decades, yet there are still several pending questions regarding how it impacts aquatic fauna. This study compared the effects of zinc exposure in its ionic- and nanoparticle forms on the mussel Mytilus galloprovincialis and sampled at different time-points. Zinc accumulation was observable after one week. Exposure to 100 µg L-1 of either form for 28 days also resulted in the higher depletion of fatty acids, lipid peroxidation products accumulation, and changes in the fatty acid profiles. This was also observed for lower concentrations, although to a smaller extent. Given the importance of fatty acids in the marine trophic chains, these zinc-induced alterations have significant potential of introducing negative impacts on the ecosystem and ultimately on human nutrition. Finally, we show that fatty acids may be used as efficient biomarkers of zinc-induced stress.
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Mytilus , Nanoparticules , Polluants chimiques de l'eau , Animaux , Écosystème , Acides gras , Humains , Polluants chimiques de l'eau/analyse , ZincRÉSUMÉ
Marine macroalgae have been increasingly targeted as a source of bioactive compounds to be used in several areas, such as biopesticides. When harvesting invasive species, such as Asparagopsis armata, for this purpose, there is a two-folded opportunity: acquiring these biomolecules from a low-cost resource and controlling its spreading and impacts. The secondary metabolites in this seaweed's exudate have been shown to significantly impact the physiology of species in the ecosystems where it invades, indicating a possible biocidal potential. Considering this in the present work, an A. armata exudate cocktail was applied in the model weed Thellungiella halophila to evaluate its physiological impact and mode of action, addressing its potential use as a natural biocide. A. armata greatly affected the test plants' physiology, namely, their photochemical energy transduction pathway (impairing light-harvesting and chemical energy production throughout the chloroplast electron transport chain), carotenoid metabolism and oxidative stress. These mechanisms of action are similar to the ones triggered when using the common chemical pesticides, highlighting the potential of the A. armata exudate cocktail as an eco-friendly biopesticide.
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Agriculture is facing major constraints with the increase of global warming, being drought a major factor affecting productivity. Soybean (Glycine max) is among the most important food crops due to the high protein and lipid content of its seeds despite being considerably sensitive to drought. Previous knowledge has shown that drought induces a severe modulation in lipid and fatty acid content of leaves, related to alteration of membrane structure by lipolytic enzymes and activation of signalling pathways. In that sense, little is known on lipid modulation and lipolytic enzymes' role in soybean drought stress tolerance. In this work, we present for the first time, soybean leaves lipid content modulation in several drought stress levels, highlighting the involvement of phospholipases A. Moreover, a comprehensive analysis of the phospholipase A superfamily was performed, where 53 coding genes were identified and 7 were selected to gene expression analysis in order to elucidate their role in soybean lipid modulation under water deficit. Proportionally to the drought severity, our results revealed that galactolipids relative abundance and their content in linolenic acid decrease. At the same time an accumulation of neutral lipids, mainly due to triacylglycerol content increase, as well as their content in linolenic acid, is observed. Overall, PLA gene expression regulation and lipid modulation corroborate the hypothesis that phospholipases A may be channelling the plastidial fatty acids into extraplastidial lipids leading to a drought-induced accumulation of triacylglycerol in soybean leaves, a key feature to cope with water stress.
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Sécheresses , Fabaceae , Phospholipases A , Glycine max/génétique , Stress physiologique , TriglycérideRÉSUMÉ
Land salinization, resulting from the ongoing climate change phenomena, is having an increasing impact on coastal ecosystems like salt marshes. Although halophyte species can live and thrive in high salinities, they experience differences in their salt tolerance range, being this a determining factor in the plant distribution and frequency throughout marshes. Furthermore, intraspecific variation to NaCl response is observed in high-ranging halophyte species at a population level. The present study aims to determine if the environmental history, namely heavy metal pre-conditioning, can have a meaningful influence on salinity tolerance mechanisms of Spartina patens, a highly disperse grass invader in the Mediterranean marshes. For this purpose, individuals from pristine and heavy metal contaminated marsh populations were exposed to a high-ranging salinity gradient, and their intraspecific biophysical and biochemical feedbacks were analyzed. When comparing the tolerance mechanisms of both populations, S. patens from the contaminated marsh appeared to be more resilient and tolerant to salt stress, this was particularly present at the high salinities. Consequently, as the salinity increases in the environment, the heavy metal contaminated marsh may experience a more resilient and better adapted S. patens community. Therefore, the heavy metal pre-conditioning of salt mash populations appears to be able to create intraspecific physiological variations at the population level that can have a great influence on marsh plant distribution outcome.