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Global climate change and the decreasing availability of high-quality water lead to an increase in the salinization of agricultural lands. This rising salinity represents a significant abiotic stressor that detrimentally influences plant physiology and gene expression. Consequently, critical processes such as seed germination, growth, development, and yield are adversely affected. Salinity severely impacts crop yields, given that many crop plants are sensitive to salt stress. Plant growth-promoting microorganisms (PGPMs) in the rhizosphere or the rhizoplane of plants are considered the second genome of plants as they contribute significantly to improving the plant growth and fitness of plants under normal conditions and when plants are under stress such as salinity. PGPMs are crucial in assisting plants to navigate the harsh conditions imposed by salt stress. By enhancing water and nutrient absorption, which is often hampered by high salinity, these microorganisms significantly improve plant resilience. They bolster the plants defenses by increasing the production of osmoprotectants and antioxidants, mitigating salt-induced damage. Furthermore, PGPMs supply growth-promoting hormones like auxins and gibberellins and reduce levels of the stress hormone ethylene, fostering healthier plant growth. Importantly, they activate genes responsible for maintaining ion balance, a vital aspect of plant survival in saline environments. This review underscores the multifaceted roles of PGPMs in supporting plant life under salt stress, highlighting their value for agriculture in salt-affected areas and their potential impact on global food security.

Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS Ds fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.

Increasing drought phenomena pose a serious threat to agricultural productivity. Although plants have multiple ways to respond to the complexity of drought stress, the underlying mechanisms of stress sensing and signaling remain unclear. The role of the vasculature, in particular the phloem, in facilitating inter-organ communication is critical and poorly understood. Combining genetic, proteomic and physiological approaches, we investigated the role of AtMC3, a phloem-specific member of the metacaspase family, in osmotic stress responses in Arabidopsis thaliana. Analyses of the proteome in plants with altered AtMC3 levels revealed differential abundance of proteins related to osmotic stress pointing into a role of the protein in water-stress-related responses. Overexpression of AtMC3 conferred drought tolerance by enhancing the differentiation of specific vascular tissues and maintaining higher levels of vascular-mediated transportation, while plants lacking the protein showed an impaired response to drought and inability to respond effectively to the hormone abscisic acid. Overall, our data highlight the importance of AtMC3 and vascular plasticity in fine-tuning early drought responses at the whole plant level without affecting growth or yield.

Streptomyces are prolific antibiotic producers that thrive in soil, where they encounter diverse environmental cues, including osmotic challenges caused by rainfall and drought. Despite their enormous value in the biotechnology sector, which often relies on ideal growth conditions, how Streptomyces react and adapt to osmotic stress is heavily understudied. This is likely due to their complex developmental biology and an exceptionally broad number of signal transduction systems. With this review, we provide an overview of Streptomyces' responses to osmotic stress signals and draw attention to open questions in this research area. We discuss putative osmolyte transport systems that are likely involved in ion balance control and osmoadaptation and the role of alternative sigma factors and two-component systems (TCS) in osmoregulation. Finally, we highlight the current view on the role of the second messenger c-di-AMP in cell differentiation and the osmotic stress responses with specific emphasis on the two models, S. coelicolor and S. venezuelae.

Potato (Solanum tuberosum L.) is one of the most important crops in the world. In addition to food and fodder, potato is also used for industrial purposes like production of adhesives, paper, and cosmetics. The vegetative growth phase of potato correlates with dry periods in spring and early summer, which are increased by climate change. Drought stress leads to morphological, physiological, and biochemical changes in the plant that have an extensive negative impact on the size and quality of the tubers. Since potato is a drought-sensitive species with its shallow root system, the interest in drought-tolerant cultivars is immense. Because ex vitro test systems are expensive and labor-intense and because additional parameters like other abiotic and biotic stressors influence the stress response, investigations in vitro are of great interest. Advantages of in vitro systems are the controlled light intensity, temperature, and supply of nutrients. Furthermore, pathogens can be excluded from the culture, and experiments require less space. Osmotic stress in vitro can be induced by adding an osmoticum, which lowers the osmotic potential in the culture medium. In the context of this work, an existing in vitro test system was optimised. For this purpose, the solid medium was replaced by liquid medium to enable that sorbitol can be added stepwise with increasing concentration. This resulted in two advantages: 1. the stress induction was gradual, and thus no osmotic shock was induced; 2. the plants were able to establish roots prior to the addition of the osmoticum, which allowed the stress that occurred by cutting the explants to be mitigated. This experiment showed that sorbitol was probably taken up by the roots and transported into the shoots, where it was detected by GC-MS. Furthermore, selected potato genotypes were investigated for their early drought stress response in open greenhouse and shelter experiments and their early osmotic stress response in vitro. For this pu

By converting physical forces into electrical signals or triggering intracellular cascades, stretch-activated ion channels allow the cell to respond to osmotic and mechanical stress. Knowledge of the pathophysiological mechanisms underlying associations of stretch-activated ion channels with human disease is limited. Here, we describe 17 unrelated individuals with severe early-onset developmental and epileptic encephalopathy (DEE), intellectual disability, and severe motor and cortical visual impairment associated with progressive neurodegenerative brain changes carrying ten distinct heterozygous variants of TMEM63B, encoding for a highly conserved stretch-activated ion channel. The variants occurred de novo in 16/17 individuals for whom parental DNA was available and either missense, including the recurrent p.Val44Met in 7/17 individuals, or in-frame, all affecting conserved residues located in transmembrane regions of the protein. In 12 individuals, hematological abnormalities co-occurred, such as macrocytosis and hemolysis, requiring blood transfusions in some. We modeled six variants (p.Val44Met, p.Arg433His, p.Thr481Asn, p.Gly580Ser, p.Arg660Thr, and p.Phe697Leu), each affecting a distinct transmembrane domain of the channel, in transfected Neuro2a cells and demonstrated inward leak cation currents across the mutated channel even in isotonic conditions, while the response to hypo-osmotic challenge was impaired, as were the Ca2+ transients generated under hypo-osmotic stimulation. Ectopic expression of the p.Val44Met and p.Gly580Cys variants in Drosophila resulted in early death. TMEM63B-associated DEE represents a recognizable clinicopathological entity in which altered cation conductivity results in a severe neurological phenotype with progressive brain damage and early-onset epilepsy associated with hematological abnormalities in most individuals.

Sexual reproduction is prevalent in eukaryotic organisms and plays a critical role in the evolution of new traits and in the generation of genetic diversity. Environmental factors often have a direct impact on the occurrence and frequency of sexual reproduction in fungi. The regulatory effects of atmospheric relative humidity (RH) on sexual reproduction and pathogenesis in plant fungal pathogens and in soil fungi have been extensively investigated. However, the knowledge of how RH regulates the lifecycles of human fungal pathogens is limited. In this study, we report that low atmospheric RH promotes the development of mating projections and same-sex (homothallic) mating in the human fungal pathogen Candida albicans. Low RH causes water loss in C. albicans cells, which results in osmotic stress and the generation of intracellular reactive oxygen species (ROS) and trehalose. The water transporting aquaporin Aqy1, and the G-protein coupled receptor Gpr1 function as cell surface sensors of changes in atmospheric humidity. Perturbation of the trehalose metabolic pathway by inactivating trehalose synthase or trehalase promotes same-sex mating in C. albicans by increasing osmotic or ROS stresses, respectively. Intracellular trehalose and ROS signal the Hog1-osmotic and Hsf1-Hsp90 signaling pathways to regulate the mating response. We, therefore, propose that the cell surface sensors Aqy1 and Gpr1, intracellular trehalose and ROS, and the Hog1-osmotic and Hsf1-Hsp90 signaling pathways function coordinately to regulate sexual mating in response to low atmospheric RH conditions in C. albicans.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disabling and chronic disease, importantly related to the current COVID-19 pandemic. Currently, there are no specific laboratory tests to directly diagnose ME/CFS. In this work, the use of impedance spectroscopy is studied as a potential technique for the diagnosis of ME/CFS. A specific device for the electrical characterization of peripheral blood mononuclear cells was designed and implemented. Impedance spectroscopy measurements in the range from 1 Hz to 500 MHz were carried out after the osmotic stress of the samples with sodium chloride solution at 1M concentration. The evolution in time after the osmotic stress at two specific frequencies (1.36 kHz and 154 kHz) was analyzed. The device showed its sensitivity to the presence of cells and the evolution of the osmotic processes. Higher values of impedance (around 15% for both the real and imaginary part) were measured at 1.36 kHz in ME/CFS patients compared to control samples. No significant difference was found between patient samples and control samples at 154 kHz. Results help to further understand the diagnosis of ME/CFS patients and the relation of their blood samples with bioimpedance measurements.

Background: This study was carried out for an understanding of the antioxidant mechanisms of field pea varieties under osmotic stress conditions caused by a lack of water. The activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx) and glutathione reductase (GR) were examined and analyzed. The gene expression levels of Cu/Zn SOD, cAPx and GR genes were also examined. Methods: Osmotic stress was stimulated using PEG 6000 with the osmotic potential of -0.1 MPa in 10 days old plant seedlings. The activity of the antioxidant enzymes was measured in the shoots and roots of pea seedlings. The gene expression levels of genes coding antioxidative enzymes were examined by the reverse transcription polymerase chain reaction (RT-PCR) technique. Arabidopsis 18S rRNA was used as endogenous control. Result: Osmotic stress changed the activities of antioxidant enzymes in the shoots and roots of pea seedlings. Varieties more tolerant to osmotic stress showed a significant increase in antioxidant activities in shoots and roots, while sensitive varieties showed a significant decrease. The results of the analysis of the expression of genes, coding for antioxidant enzymes, showed that the reaction of the tested cultivars to ROS was the result of increased expression of the tested genes in tolerant cultivars, i.e. decreased expression in sensitive cultivars.

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.

Human- and nature-induced hypersaline conditions in coastal systems can lead to profound alterations of the structure and vitality of seagrass meadows and their socio-ecological benefits. In the last two decades, recent research efforts (>50 publications) have contributed significantly to unravel the physiological basis underlying the seagrass-hypersalinity interactions, although most (∼70%) are limited to few species (e.g. Posidonia oceanica, Zostera marina, Thalassia testudinum, Cymodocea nodosa). Variables related to photosynthesis and carbon metabolism are among the most prevalent in the literature, although other key metabolic processes such as plant water relations and responses at molecular (i.e. gene expression) and ultrastructure level are attracting attention. This review emphasises all these latest insights, offering an integrative perspective on the interplay among biological responses across different functional levels (from molecular to clonal structure), and their interaction with biotic/abiotic factors including those related to climate change. Other issues such as the role of salinity in driving the evolutionary trajectory of seagrasses, their acclimation mechanisms to withstand salinity increases or even the adaptive properties of populations that have historically lived under hypersaline conditions are also included. The pivotal role of the costs and limits of phenotypic plasticity in the successful acclimation of marine plants to hypersalinity is also discussed. Finally, some lines of research are proposed to fill the remaining knowledge gaps.

Increasing drought phenomena pose a serious threat to agricultural productivity. Although plants have multiple ways to respond to the complexity of drought stress, the underlying mechanisms of stress sensing and signaling remain unclear. The role of the vasculature, in particular the phloem, in facilitating inter-organ communication is critical and poorly understood. Combining genetic, proteomic and physiological approaches, we investigated the role of AtMC3, a phloem-specific member of the metacaspase family, in osmotic stress responses in Arabidopsis thaliana. Analyses of the proteome in plants with altered AtMC3 levels revealed differential abundance of proteins related to osmotic stress pointing into a role of the protein in water-stress-related responses. Overexpression of AtMC3 conferred drought tolerance by enhancing the differentiation of specific vascular tissues and maintaining higher levels of vascular-mediated transportation, while plants lacking the protein showed an impaired response to drought and inability to respond effectively to the hormone abscisic acid. Overall, our data highlight the importance of AtMC3 and vascular plasticity in fine-tuning early drought responses at the whole plant level without affecting growth or yield.

Mitochondria, organelles found in the cytoplasm of almost all eukaryotic cells, generate large quantities of energy in the form of adenosine triphosphate (ATP). In addition to producing energy, mitochondria store calcium for cell signaling activities and play an important role in maintenance of ionic balance. Mitochondria, however, are highly sensitive to any kind of stress in which they mainly response by disturbance of respiration, reactive oxygen species (ROS) production and release of cytochrome c into the cytoplasm. Osmotic stress, in particular, generates ROS that degrade lipids, proteins, and DNA. High levels of salt concentration can cause an imbalance in cellular ion homeostasis that results in ion toxicity and osmotic stress. This study aims to investigate possible effects of KCl and NaCl on Bone marrow-derived (MSCs) mitochondria membrane potential (MMP) and morphology. The results indicated that KCl and NaCl of salt concentration can cause an imbalance in cellular ion homeostasis that results in ion toxicity and osmotic stress. This study aims to investigate possible effects of KCl and NaCl on MSCs mitochondria membrane potential (MMP) and morphology. The results indicated that KCl and NaCl decreased the potential and changed the morphology of mitochondria membrane compared to cells growing in normal condition.

Abscisic acid (ABA) is a plant hormone that regulates various responses to environmental stress and plant development. In the study, the transcriptional responses of Arabidopsis seedlings to ABA at concentrations ranging from 0.001 to 100 micromolar were analyzed. A total of 5749 ABA-responsive genes were identified, which can be grouped into nine clusters based on their dose-dependent response profiles. Approximately 20% of these genes showed atypical biphasic (bell-shaped or U-shaped) dose-response trends and were found to participate in specific biological processes including water transport. The sensitivity of ABA-responsive genes to ABA was also determined using effective dose (ED50) and benchmark dose (BMD) values. ABA receptors, which play a key role in ABA signaling, are encoded by 14 genes in three subfamilies with differing oligomeric states and ABA affinities. The transcriptional responses of mutant strains lacking each subfamily of ABA receptors were compared to the wild type using RNA sequencing. The results showed that the removal of subfamily III receptors had the largest effect on ABA-regulated gene expression, indicating the importance of these receptors in Arabidopsis seedlings. Additionally, the role of ABA signaling in osmotic stress was examined using an ABA receptor antagonist, antabactin (ANT), during osmotic stress caused by PEG treatment. The ABA dependency of genes under osmotic stress was quantitatively defined using a ?-value, which has a higher value when the effect of ANT increases. Motif analyses of cis-elements in the promoter regions of genes revealed a correlation between ABA dependency and the enrichment of ABA-related motifs. This study also reveals that the majority of osmotic-stress-responsive genes formerly classified as ABA-independent require ABA signaling for proper osmotic stress. Overall, this study provides insight into the complexity of the ABA signaling network and identifies a set of transcriptional markers for charact

Mitochondria, organelles found in the cytoplasm of almost all eukaryotic cells, generate large quantities of energy in the form of adenosine triphosphate (ATP). In addition to producing energy, mitochondria store calcium for cell signaling activities and play an important role in maintenance of ionic balance. Mitochondria, however, are highly sensitive to any kind of stress in which they mainly response by disturbance of respiration, reactive oxygen species (ROS) production and release of cytochrome c into the cytoplasm. Osmotic stress, in particular, generates ROS that degrade lipids, proteins, and DNA. High levels of salt concentration can cause an imbalance in cellular ion homeostasis that results in ion toxicity and osmotic stress. This study aims to investigate possible effects of KCl and NaCl on Bone marrow-derived (MSCs) mitochondria membrane potential (MMP) and morphology. The results indicated that KCl and NaCl of salt concentration can cause an imbalance in cellular ion homeostasis that results in ion toxicity and osmotic stress. This study aims to investigate possible effects of KCl and NaCl on MSCs mitochondria membrane potential (MMP) and morphology. The results indicated that KCl and NaCl decreased the potential and changed the morphology of mitochondria membrane compared to cells growing in normal condition.

Abiotic stresses can cause significant damage to plants. For sustainable bioenergy crop production, it is critical to generate resistant crops to such stress. Engineering promoters to control the precise expression of stress resistance genes is a very effective way to address the problem. Here we developed stably transformed Populus tremula × Populus alba hybrid poplar (INRA 717-1B4) containing one-of-six synthetic drought stress-inducible promoters (SDs; SD9-1, SD9-2, SD9-3, SD13-1, SD18-1, and SD18-3) identified previously by transient transformation assays. We screened green fluorescent protein (GFP) induction in poplar under osmotic stress conditions. Of six transgenic lines containing synthetic promoter, three lines (SD18-1, 9-2, and 9-3) had significant GFP expression in both salt and osmotic stress treatments. Each synthetic promoter employed heptamerized repeats of specific and short cis-regulatory elements (7 repeats of 7-8 bases). To verify whether the repeats of longer sequences can improve osmotic stress responsiveness, a transgenic poplar containing the synthetic promoter of the heptamerized entire SD9 motif (20 bases, containing all partial SD9 motifs) was generated and measured for GFP induction under osmotic stress. The heptamerized entire SD9 motif did not result in higher GFP expression than the shorter promoters consisting of heptamerized SD9-1, 9-2, and 9-3 (partial SD9) motifs. This result indicates that shorter synthetic promoters (~50 bp) can be used for versatile control of gene expression in transgenic poplar. These synthetic promoters will be useful tools to engineer stress-resilient bioenergy tree crops in the future.

Mitochondria, organelles found in the cytoplasm of almost all eukaryotic cells, generate large quantities of energy in the form of adenosine triphosphate (ATP). In addition to producing energy, mitochondria store calcium for cell signaling activities and play an important role in maintenance of ionic balance. Mitochondria, however, are highly sensitive to any kind of stress in which they mainly response by disturbance of respiration, reactive oxygen species (ROS) production and release of cytochrome c into the cytoplasm. Osmotic stress, in particular, generates ROS that degrade lipids, proteins, and DNA. High levels of salt concentration can cause an imbalance in cellular ion homeostasis that results in ion toxicity and osmotic stress. This study aims to investigate possible effects of KCl and NaCl on Bone marrow-derived (MSCs) mitochondria membrane potential (MMP) and morphology. The results indicated that KCl and NaCl of salt concentration can cause an imbalance in cellular ion homeostasis that results in ion toxicity and osmotic stress. This study aims to investigate possible effects of KCl and NaCl on MSCs mitochondria membrane potential (MMP) and morphology. The results indicated that KCl and NaCl decreased the potential and changed the morphology of mitochondria membrane compared to cells growing in normal condition.

The alternative oxidase (AOX) is a monotopic metalloprotein attached to the inner surface of the inner mitochondrial membrane. This enzyme catalyzes the transfer of electrons from ubiquinol to oxygen, with the production of water. When the cytochrome pathway is inhibited by cyanide or other xenobiotic molecules, the AOX allows the flux of electrons from NADH to oxygen and thus, the catabolic and anabolic activity of the Krebs cycle. The AOX is found in plants, fungi, some protists and a few primitive metazoans. It has been proposed that this enzyme has important roles in the response against osmotic and oxidative stresses. In this review, we analyze the structure of the enzyme, address its participation in the responses of fungi to osmotic stress and analyze the influence of AOX on ATP synthesis., La oxidasa alterna (AOX) es una metaloproteína monotópica que se encuentra unida a la cara interna de la membrana interna mitocondrial. Esta enzima cataliza la transferencia de electrones del ubiquinol al oxígeno con formación de agua como uno de los productos. Cuando la vía citocrómica se inhibe por la presencia de cianuro u otros agentes xenobióticos, la AOX permite el flujo de electrones del NADH al oxígeno y, por tanto, la actividad catabólica y anabólica del ciclo de Krebs. La AOX se encuentra en plantas, hongos, algunos protistas y metazoarios primitivos y se le ha atribuido la capacidad de conferir osmoprotección y resistencia al estrés oxidativo en las células. En esta revisión, se analiza la estructura de la enzima, se aborda su participación en la respuesta ante el estrés osmótico y oxidativo en hongos, su influencia en la síntesis de ATP y la regulación de su expresión genética.

Chenopodium album L. and Chenopodium murale L. are two principal weed species, causing substantial damage to numerous winter crops across the globe. For sustainable and resource-efficient management strategies, it is important to understand weeds’ germination behaviour under diverse conditions. For the germination investigations, seeds of both species were incubated for 15 days under different temperatures (10–30 °C), salinity (0–260 mM NaCl), osmotic stress (0–1 MPa), pH (4–10), and heating magnitudes (50–200 °C). The results indicate that the germination rates of C. album and C. murale were 54–95% and 63–97%, respectively, under a temperature range of 10 to 30 °C. The salinity levels for a 50% reduction in the maximum germination (GR50) for C. album and C. murale were 139.9 and 146.3 mM NaCl, respectively. Regarding osmotic stress levels, the GR50 values for C. album and C. murale were 0.44 and 0.43 MPa, respectively. The two species showed >95% germination with exposure to an initial temperature of 75 °C for 5 min; however, seeds exposed to 100 °C and higher temperatures did not show any germination. Furthermore, a drastic reduction in germination was observed when the pH was less than 6.0 and greater than 8.0. The study generated information on the germination biology of two major weed species under diverse ecological scenarios, which may be useful in developing efficient weed management tactics for similar species in future agri-food systems.

Camelina sativa (L.) Crantz, is a self-pollinated, annual oilseed from the Brassicaceae family, which is gaining interest worldwide due to its frost, heat, and drought tolerance. The aim of this study was to evaluate camelina germination under osmotic stress, and to identify critical soil moisture levels for successful germination establishment. A germination test was set up in controlled conditions, comparing six winter and six spring genotypes with differing seed sizes (ranging from 0.88 to 1.83 g/1000-seeds) under increasing levels of osmotic stress (0, −0.4, −0.8, −1.2, −1.4, −1.6 MPa) that was produced with polyethylene glycol (PEG). The results showed good tolerance of all camelina genotypes to drought at the germination stage. Plants remained unaffected at mild level of osmotic stress (−0.4 MPa) having no significant decrease in germination percentage compared with the control. Even at −1.2 MPa, examined genotypes still had high germination (75%). Significant differences in germination were observed be-tween biotypes, where spring biotypes performed better than winter ones. Shoot and radicle lengths were significantly diminished by imposed osmotic stress, but shoot growth seemed more impacted. In general, spring biotypes had longer shoots and radicles than winter ones. Seed size played a role in the response of camelina to drought, but it depended on biotype and stress level imposed. Camelina confirmed to withstand high levels of drought stress at germination and could be considered as more suitable oil crop than oilseed rape on marginal lands, or areas with irregular precipitation pattern.

Due to different functions of phosphate solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF), their potential synergistic effects on enhancing plant growth and yield are worth investigating, especially under adverse conditions. This work focused on the isolation of PSB and characterization for their plant growth promoting properties under drought. The most efficient P solubilizing bacterium was isolated and identified as Burkholderia vietnamiensis strain KKUT8-1. Then, a factorial experiment on the performance of sunchoke (Helianthus tuberosus) was set up with four factors, viz., PSB (presence or absence of KKUT8-1), AMF (presence or absence of Rhizophagus aggregatus), rock phosphate (RP; added or not) and moisture (well-watered (WW) or drought (DS) conditions). Sunchoke performance was enhanced by the presence of AMF, whereas addition of PSB had a positive effect on SPAD values and inulin concentration. Drought reduced plant performance, while addition of RP reduced photosynthetic rate. There was little evidence for synergistic effects between PSB and AMF, except for SPAD values and inulin concentration. Plants that were co-inoculated with AMF and PSB had highest SPAD value, shoot diameter, leaf area, leaf number, chlorophyll concentration, plant biomass, tuber production, root growth and total soluble sugar concentration. Co-inoculated plants also had increased plant water status, reduced electrolyte leakage, and reduced malondialdehyde and proline concentration. Strain KKUT8-1 is the first strain of B. vietnamiensis capable of promoting growth and yield of sunchoke. Enhanced production of sunchoke by a combination of AMF and PSB was much better than the application of RP. Our finding offers an opportunity to develop combinations of biological inoculants for increasing the growth and production of sunchoke under drought in the future.

Camelina [Camelina sativa (L.) Crantz] has increased cold, heat, and drought tolerance and decreased susceptibility to diseases and pests than oilseed rape (Brassica napus L.). Because water deficit at sowing leads to unsatisfactory stand establishment due to irregular seed germination and emergence, the aim of this study was to understand the response of camelina germination under osmotic stress and identify critical soil moisture levels for successful establishment. Two spring cultivars, NS Slatka and NS Zlatka, developed at the Institute of Field and Vegetable Crops Novi Sad, Serbia, were compared under 9 levels of osmotic stress, ranging from 0 MPa to - 1.6 MPa. Polyethylene glycol was used to obtain the osmotic potential of the solutions. Results showed that the tested cultivars did not decrease germination under mild and medium osmotic stress levels (down to - 0.8 MPa). However, germination significantly decreased in both cultivars under higher levels of osmotic stress, and NS Zlatka was more sensitive. Germination speed significantly increased at - 0.4 MPa. The estimated osmotic potentials to stop germination were - 1.45 MPa for NS Slatka and - 1.46 MPa for NS Zlatka. Time to 50% germination also showed a significant bi-linear trend in response to osmotic potential, but in the opposite direction than the one observed in germination. Inflection points were recorded at - 0.77 MPa for NS Slatka and - 0.78 MPa for NS Zlatka, thereafter time to 50% of germination rapidly increased. This study confirmed that camelina can withstand increased levels of drought stress at germination, so it could be considered a more suitable option than oilseed rape on marginal land, or environments with irregular precipitation.

The prevalence of Aspergillus fumigatus colonization in individuals with cystic fibrosis (CF) and subsequent fungal persistence in the lung is increasingly recognized. However, there is no consensus for clinical management of A. fumigatus in CF individuals, due largely to uncertainty surrounding A. fumigatus CF pathogenesis and virulence mechanisms. To address this gap in knowledge, a longitudinal series of A. fumigatus isolates from an individual with CF were collected over 4.5 years. Isolate genotypes were defined with whole-genome sequencing that revealed both transitory and persistent A. fumigatus in the lung. Persistent lineage isolates grew most readily in a low-oxygen culture environment, and conidia were more sensitive to oxidative stress-inducing conditions than those from nonpersistent isolates. Closely related persistent isolates harbored a unique allele of the high-osmolarity glycerol (HOG) pathway mitogen-activated protein kinase kinase, Pbs2 (pbs2C2). Data suggest this novel pbs2C2 allele arose in vivo and is necessary for the fungal response to osmotic stress in a low-oxygen environment through hyperactivation of the HOG (SakA) signaling pathway. Hyperactivation of the HOG pathway through pbs2C2 comes at the cost of decreased conidial stress resistance in the presence of atmospheric oxygen levels. These novel findings shed light on pathoadaptive mechanisms of A. fumigatus in CF, lay the foundation for identifying persistent A. fumigatus isolates that may require antifungal therapy, and highlight considerations for successful culture of persistent Aspergillus CF isolates. IMPORTANCE Aspergillus fumigatus infection causes a spectrum of clinical manifestations. For individuals with cystic fibrosis (CF), allergic bronchopulmonary aspergillosis (ABPA) is an established complication, but there is a growing appreciation for A. fumigatus airway persistence in CF disease progression. There currently is little consensus for clinical management of A. fumigatus l

Haloarchaea produce C50 carotenoids such as bacterioruberin, which are of biotechnological in-terest. This study aimed to analyze the effect of different environmental and nutritional conditions on the cellular growth and dynamics of carotenoids accumulation in Haloferax mediterranei. The maximum production of carotenoids (40 µg·mL−1) was obtained during the stationary phase of growth, probably due to nutrient-limiting conditions (one-step culture). By seven days of culture, 1 mL culture produced 22.4 mg of dry weight biomass containing 0.18 % (w/w) of carotenoids. On the other hand, carbon-deficient cultures (low C/N ratio) were observed to be optimum for C50 bacterioruberin production by Hfx. mediterranei, but negatively affected the growth of cells. Thus, a two-steps process was evaluated for optimum carotenoids yield. In the first step, a nutri-ent-repleted culture medium enabled the haloarchaea to produce biomass, while in the second step, the biomass was incubated under osmotic stress and in a carbon-deficient medium. Under the conditions used, the obtained biomass contained 0.27% (w/w) of carotenoids after seven days, which accounts for 58.49 µg·mL−1 of carotenoids for a culture with turbidity 14.0.

In the present investigation, effect of osmotic stress imposed by the supply of sorbitol was analyzed on biochemical parameters, such as, protein, RNA, DNA and proline content in leaves of Zea mays, Ganga Safed-2 genotype. For the study, maize leaf segments obtained from light grown seedlings were treated with varying concentrations of sorbitol (0.0-1.0 M) under illumination. Total protein, total RNA and DNA were found to decrease markedly and significantly by the supplementation of 0.2 to 1.0 M sorbitol in excised leaf segments. The relative water content decreased marginally with the sorbitol treatment, but a several-fold increase in proline content was noted. SDS- PAGE analysis of sorbitol treated maize leaf tissue revealed the appearance of a protein (approx. 70 kDa) in 0.6M sorbitol treatment. Further, extensive homology (Protein score: 270) was found for that protein with chloroplast heat shock protein 70 from Cenchrus americanus. Concentration-dependent decrease in total chlorophylls and carotenoids was observed with an increasing supply of the osmotic inducer. It is suggested that sorbitol interferes with the growth and metabolic parameters of the Zea mays Ganga Safed-2 leaf tissue and stimulates the synthesis of stress induced proteins.

The growth and productivity of several apple rootstocks have been evaluated in various previous studies. However, limited information is available on their tolerance to osmotic stress. In the present study, the physiological and molecular responses as well as abscisic acid (ABA) levels were assessed in six apple rootstocks (M26, V3, G41, G935, B9 and B118) osmotically stressed with polyethylene glycol (PEG, 30%) application under greenhouse conditions. Our results showed that V3, G41, G935 and B9 had higher relative water content (RWC), and lower electrolyte leakage (EL) under stress conditions compared to M26 and B118. Additionally, water use efficiency (WUE) was higher in V3, G41 and B9 than M26, which might be partially due to the lower transpiration rate in these tolerant rootstocks. V3, G41 and B9 rootstocks also displayed high endogenous ABA levels which was combined with a reduction in stomatal conductance and decreased water loss. At the transcriptional level, genes involved in ABA-dependent and ABA-independent pathways, e.g., SnRK, DREB, ERD and MYC2, showed higher expression in V3, G41, G935 and B9 rootstocks compared to M26 in response to stress. In contrast, WRKY29 was down-regulated in response to stress in the tolerant rootstocks, and its expression was negatively correlated with ABA content and stomatal closure. Overall, the findings of this study showed that B9, V3 and G41 displayed better osmotic stress tolerance followed by G935 then M26 and B118 rootstocks.

In grafted plants, the movement of long-distance signals from rootstocks can modulate the development and function of the scion. To understand the mechanisms by which tolerant rootstocks improve scion responses to osmotic stress (OS) conditions, mRNA transport of osmotic responsive genes (ORGs) was evaluated in a tomato/potato heterograft system. In this system, Solanum tuberosum was used as a rootstock and Solanum lycopersicum as a scion. We detected changes in the gene expression levels of 13 out of the 21 ORGs tested in the osmotically stressed plants; of these, only NPR1 transcripts were transported across the graft union under both normal and OS conditions. Importantly, OS increased the abundance of StNPR1 transcripts in the tomato scion. To examine mRNA mobility in transgrafted plants, StNPR1 and StDREB1 genes representing the mobile and non-mobile transcripts, respectively, were overexpressed in tobacco (Nicotiana tabacum). The evaluation of transgenic tobacco plants indicated that overexpression of these genes enhanced the growth and improved the physiological status of transgenic plants growing under OS conditions induced by NaCl, mannitol and polyethylene glycol (PEG). We also found that transgenic tobacco rootstocks increased the OS tolerance of the WT-scion. Indeed, WT scions on transgenic rootstocks had higher ORGs transcript levels than their counterparts on non-transgenic rootstocks. However, neither StNPR1 nor StDREB1 transcripts were transported from the transgenic rootstock to the wild-type (WT) tobacco scion, suggesting that other long-distance signals downstream these transgenes could have moved across the graft union leading to OS tolerance. Overall, our results signify the importance of StNPR1 and StDREB1 as two anticipated candidates for the development of stress-resilient crops through transgrafting technology.

Haloarchaea produce C50 carotenoids such as bacterioruberin, which are of biotechnological in-terest. This study aimed to analyze the effect of different environmental and nutritional conditions on the cellular growth and dynamics of carotenoids accumulation in Haloferax mediterranei. The maximum production of carotenoids (40 µg·mL−1) was obtained during the stationary phase of growth, probably due to nutrient-limiting conditions (one-step culture). By seven days of culture, 1 mL culture produced 22.4 mg of dry weight biomass containing 0.18 % (w/w) of carotenoids. On the other hand, carbon-deficient cultures (low C/N ratio) were observed to be optimum for C50 bacterioruberin production by Hfx. mediterranei, but negatively affected the growth of cells. Thus, a two-steps process was evaluated for optimum carotenoids yield. In the first step, a nutri-ent-repleted culture medium enabled the haloarchaea to produce biomass, while in the second step, the biomass was incubated under osmotic stress and in a carbon-deficient medium. Under the conditions used, the obtained biomass contained 0.27% (w/w) of carotenoids after seven days, which accounts for 58.49 µg·mL−1 of carotenoids for a culture with turbidity 14.0.

The epidermis is composed of multiple cell strata where viable keratinocytes, in the basal layer (stratum basale (SB)), go through a range of steps with the final stage of being dead corneocytes in the outer most layer (stratum corneum (SC)). The differentiation, which can be thought of as programmed cell death, include several key processes that are essential for an intact skin barrier. The route from SB to SC is accompanied by changes, such as osmotic pressure and pH, that are believed to trigger some of these processes. In this project, HaCaT cells were incubated with, commonly used, skin care substances (urea, glycerol, transcutol and salicylic acid) to assess their impact on cell viability, by MTT-assay, and gene expression, by qPCR. Further, the relationship between osmotic pressure, viability and gene expression was studied. The excipients showed a dose-dependent decrease of keratinocyte viability which also was explained by elevated osmotic pressure when concentration was increased. Exceptions were however observed for transcutol, which showed protective features against osmotic stress. Upregulation of the genes were mainly observed when cells were treated with high concentrations. Involucrin was affected by the substances to a greater extent when compared to other markers. The upregulation of involucrin was however seen to be driven by the osmotic pressure rather than biological effects of the molecules. The project conclude that the viability and gene expression of the keratinocytes are highly related to the osmotic pressure and probably influences the differentiation to a greater extent than the molecules themselves.

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.

Chloride (Cl−) is required for photosynthesis and regulates osmotic balance. However, excess Cl− application negatively interacts with nitrate (NO−3) uptake, although its effect on NO−3 metabolism remains unclear. The aim was to test whether Cl− stress disturbs nitrate reductase activity (NRA). A maize variety (Zea mays L. cv. LG 30215) was hydroponically cultured in a greenhouse under the following conditions: control (2 mM CaCl2), moderate Cl− (10 mM CaCl2), high Cl− (60 mM CaCl2). To substantiate the effect of Cl− stress further, an osmotic stress with lower intensity was induced by 60 g polyethylene glycol (PEG) 6000 L−1 + 2 mM CaCl2), which was 57% of the osmotic pressure being produced by 60 mM CaCl2. Results show that high Cl− and PEG-induced osmotic stress significantly reduced shoot biomass, stomatal conductance and transpiration rate, but NRA was only decreased by high Cl− stress. The interference of NRA in chloride-stressed maize is supposed to be primarily caused by the antagonistic uptake of Cl− and NO−3., Peer Reviewed

The growth and productivity of several apple rootstocks have been evaluated in various previous studies. However, limited information is available on their tolerance to osmotic stress. In the present study, the physiological and molecular responses as well as abscisic acid (ABA) levels were assessed in six apple rootstocks (M26, V3, G41, G935, B9 and B118) osmotically stressed with polyethylene glycol (PEG, 30%) application under greenhouse conditions. Our results showed that V3, G41, G935 and B9 had higher relative water content (RWC), and lower electrolyte leakage (EL) under stress conditions compared to M26 and B118. Additionally, water use efficiency (WUE) was higher in V3, G41 and B9 than M26, which might be partially due to the lower transpiration rate in these tolerant rootstocks. V3, G41 and B9 rootstocks also displayed high endogenous ABA levels which was combined with a reduction in stomatal conductance and decreased water loss. At the transcriptional level, genes involved in ABA-dependent and ABA-independent pathways, e.g., SnRK, DREB, ERD and MYC2, showed higher expression in V3, G41, G935 and B9 rootstocks compared to M26 in response to stress. In contrast, WRKY29 was down-regulated in response to stress in the tolerant rootstocks, and its expression was negatively correlated with ABA content and stomatal closure. Overall, the findings of this study showed that B9, V3 and G41 displayed better osmotic stress tolerance followed by G935 then M26 and B118 rootstocks.

In grafted plants, the movement of long-distance signals from rootstocks can modulate the development and function of the scion. To understand the mechanisms by which tolerant rootstocks improve scion responses to osmotic stress (OS) conditions, mRNA transport of osmotic responsive genes (ORGs) was evaluated in a tomato/potato heterograft system. In this system, Solanum tuberosum was used as a rootstock and Solanum lycopersicum as a scion. We detected changes in the gene expression levels of 13 out of the 21 ORGs tested in the osmotically stressed plants; of these, only NPR1 transcripts were transported across the graft union under both normal and OS conditions. Importantly, OS increased the abundance of StNPR1 transcripts in the tomato scion. To examine mRNA mobility in transgrafted plants, StNPR1 and StDREB1 genes representing the mobile and non-mobile transcripts, respectively, were overexpressed in tobacco (Nicotiana tabacum). The evaluation of transgenic tobacco plants indicated that overexpression of these genes enhanced the growth and improved the physiological status of transgenic plants growing under OS conditions induced by NaCl, mannitol and polyethylene glycol (PEG). We also found that transgenic tobacco rootstocks increased the OS tolerance of the WT-scion. Indeed, WT scions on transgenic rootstocks had higher ORGs transcript levels than their counterparts on non-transgenic rootstocks. However, neither StNPR1 nor StDREB1 transcripts were transported from the transgenic rootstock to the wild-type (WT) tobacco scion, suggesting that other long-distance signals downstream these transgenes could have moved across the graft union leading to OS tolerance. Overall, our results signify the importance of StNPR1 and StDREB1 as two anticipated candidates for the development of stress-resilient crops through transgrafting technology.

Water is indispensable for the life of any organism on Earth. Consequently, osmotic stress due to salinity and drought is the greatest threat to crop productivity. Ongoing climate change includes rising temperatures and less precipitation over large areas of the planet. This is leading to increased vulnerability to the drought conditions that habitually threaten food security in many countries. Such a scenario poses a daunting challenge for scientists: the search for innovative solutions to save water and cultivate under water deficit. A search for formulations including biostimulants capable of improving tolerance to this stress is a promising specific approach. This review updates the most recent state of the art in the field.

Yield losses due to cultivation in saline soils is a common problem all over the world as most crop plants are glycophytes and, hence, susceptible to salt stress. The use of halophytic crops could be an interesting alternative to cope with this issue. The Amaranthaceae family comprises by far the highest proportion of salt-tolerant halophytic species. Amaranth and quinoa belong to this family, and their seeds used as pseudo-cereal grains have received much attention in recent years because of their exceptional nutritional value. While advances in the knowledge of salt tolerance mechanisms of quinoa have been remarkable in recent years, much less attention was received by amaranth, despite evidences pointing to amaranth as a promising species to be grown under salinity. In order to advance in the understanding of strategies used by amaranth to confront salt stress, we studied the comparative responses of amaranth and quinoa to salinity (100 mM NaCl) at the physiological, anatomical, and molecular levels. Amaranth was able to exhibit salt tolerance throughout its life cycle, since grain production was not affected by the saline conditions applied. The high salt tolerance of amaranth is associated with a low basal stomatal conductance due to a low number of stomata (stomatal density) and degree of stomata aperture (in adaxial surface) of leaves, which contributes to avoid leaf water loss under salt stress in a more efficient way than in quinoa. With respect to Na homeostasis, amaranth showed a pattern of Na distribution throughout the plant similar to glycophytes, with the highest accumulation found in the roots, followed by the stem and the lowest one detected in the leaves. Contrarily, quinoa exhibited a Na includer character with the highest accumulation detected in the shoots. Expression levels of main genes involved in Na homeostasis (SOS1, HKT1s, and NHX1) showed different patterns between amaranth and quinoa, with a marked higher basal expression in amaranth roo

Hemp (Cannabis sativa L.) is a multi-purpose industrial species, which is valued as a low-input crop suited to marginal environments. However, research on the water stress resistance and water use efficiency of hemp cultivars is scarce. Three lab-scale experiments were carried out to test 26 commercial European hemp cultivars under osmotic stress at germination (experiment 1) and on plantlets at vegetative stage (experiment 2); and to calculate transpiration efficiency (TE) under well-watered conditions (experiment 3). Eight parameters were analysed: maximum germination percentage, lag time and germination homogeneity in experiment 1; maximum quantum yield of PSII (Fv/Fm), performance index, relative water content and proline content in experiment 2; TE in experiment 3. Osmotic stress application significantly affected all parameters in experiments 1 and 2, and responses to water stress differed significantly among cultivars for all parameters, except proline content. Considering all parameters except proline content, a principal component analysis was carried out for ranking the cultivars. The cultivars 'Carmaleonte', 'Codimono', 'Futura 75' and Santhica '70' ranked the highest, while cultivars 'Bialobrzeskie', 'Ermes' and 'Finola' had the worst performances for all traits.

Camelina [Camelina sativa (L.) Crantz] is native species of Eurasia, which is gaining interest world wide due to its better cold, heat, and drought tolerance, and less susceptibility to disease and pests than oilseed rape (Brassica napus L.). Furthermore, studies conducted in Canada and USA reported that as far as yield is concerned, camelina could be competitive against other Brassicas. Water shortage during germination is one of the major constraints that induces irregular and delayed seed germination and emergence, leading to poor plant establishment. Camelina has relatively low water requirement and high tolerance to drought, at all stages of development, even at germination and early seedling growth. Aiming at understanding the response of camelina germination under osmotic stress and the identification of critical soil moisture levels for successful establishment, two spring cultivars, developed at the Institute of Field and Vegetable crops Novi Sad, were compared (NS Slatka and NS Zlatka) under 9 levels of osmotic stress, ranging from 0 MPa to -1.6 MPa. Seeds were kept at 20°C and 8/16 h light/dark cycle. Osmotic potential of solution was obtained by using polyethylene glycol. Seeds were considered germinated when radicle was at least 2-mm-long. Germination was surveyed daily, while final germination was determined when no germinated seeds were recorded for 3 consecutive d, or after 15 d of incubation.

Debaryomyces hansenii is traditionally described as a halotolerant non-conventional yeast, and has served as a model organism for the study of osmo- and salt tolerance mechanisms in eukaryotic systems for the past 30 years. However, unravelling of D. hansenii´s biotechnological potential has always been difficult due to the persistent limitations in the availability of efficient molecular tools described for this yeast. Additionally, there is a lack of consensus and contradictory information along the recent years that limits a comprehensive understanding of its central carbon metabolism, mainly due to a lack of physiological studies in controlled and monitored environments. Moreover, there is little consistency in the culture conditions (media composition, temperature and pH among others) used by different groups, which makes it complicated when trying to get prevalent conclusions on behavioural patterns. In this work, we present for the first time a characterization of D. hansenii in batch cultivations using highly controlled lab-scale bioreactors. Our findings contribute to a more complete picture of the central carbon metabolism and the external pH influence on the yeast’s ability to tolerate high Na+ and K+ concentrations, pointing to a differential effect of both salts, as well as a positive effect in cell performance when low environmental pH values are combined with a high sodium concentration in the media. Finally, a novel survival strategy at very high salinity (2 M) is proposed for this yeast, as well as potential outcomes for its use in industrial biotechnology applications.

Salinity is one of the main causes of abiotic stress in plants, resulting in negative effects on crop growth and yield, especially in arid and semi-arid regions. The effects of salinity on plant growth mainly generate osmotic stress, ion toxicity, nutrient deficiency, and oxidative stress. Traditional approaches for the development of salt-tolerant crops are expensive and time-consuming, as well as not always being easy to implement. Thus, the use of plant growth-promoting bacteria (PGPB) has been reported as a sustainable and cost-effective alternative to enhance plant tolerance to salt stress. In this sense, this review aims to understand the mechanisms by which PGPB help plants to alleviate saline stress, including: (i) changes in the plant hormonal balance; (ii) release of extracellular compounds acting as chemical signals for the plant or enhancing soil conditions for plant development; (iii) regulation of the internal ionic content of the plant; or iv) aiding in the synthesis of osmoprotectant compounds (which reduce osmotic stress). The potential provided by PGPB is therefore an invaluable resource for improving plant tolerance to salinity, thereby facilitating an increase in global food production and unravelling prospects for sustainable agricultural productivity

Protein mobility in the cytoplasm is essential for cellular functions, and slow diffusion may limit the rates of biochemical reactions in the living cell. Here, we determined the apparent lateral diffusion coefficient (DL) of GFP in Listeria monocytogenes as a function of osmotic stress, temperature, and media composition. We find that DL is much less affected by hyperosmotic stress in L. monocytogenes than under similar conditions in Lactococcus lactis and Escherichia coli. We find a temperature optimum for protein diffusion in L. monocytogenes at 30°C, which deviates from predicted trends from the generalized Stokes-Einstein equation under dilute conditions and suggests that the structure of the cytoplasm and macromolecular crowding vary as a function of temperature. The turgor pressure of L. monocytogenes is comparable to other Gram-positive bacteria like Bacillus subtilis and L. lactis but higher in a knockout strain lacking the stress-inducible sigma factor SigB. We discuss these findings in the context of how L. monocytogenes survives during environmental transmission and interaction with the human host.

Beta (beta)-glucans are polysaccharides composed of D-glucose monomers. Nowadays, beta-glucans are gaining attention due to their attractive immunomodulatory biological activities, which can be utilized in pharmaceutical or food supplementation industries. Some carotenogenicBasidiomycetesyeasts, previously explored for lipid and carotenoid coproduction, could potentially coproduce a significant amount of beta-glucans. In the present study, we screened elevenBasidiomycetesfor the coproduction of lipids and beta-glucans. We examined the effect of four different C/N ratios and eight different osmolarity conditions on the coproduction of lipids and beta-glucans. A high-throughput screening approach employing microcultivation in microtiter plates, Fourier Transform Infrared (FTIR) spectroscopy and reference analysis was utilized in the study. Yeast strainsC. infirmominiatumCCY 17-18-4 andR. kratochvilovaeCCY 20-2-26 were identified as the best coproducers of lipids and beta-glucans. In addition,C. infirmominiatumCCY 17-18-4,R. kratochvilovaeCCY 20-2-26 andP. rhodozymaCCY 77-1-1 were identified as the best alternative producers of beta-glucans. Increased C/N ratio led to increased biomass, lipid and beta-glucans production for several yeast strains. Increased osmolarity had a negative effect on biomass and lipid production while the beta-glucan production was positively affected.

The filamentous fungus Aspergillus fumigatus can cause a distinct set of clinical disorders in humans. Invasive aspergillosis (IA) is the most common life-threatening fungal disease of immunocompromised humans. The mitogen-activated protein kinase (MAPK) signaling pathways are essential to the adaptation to the human host. Fungal cell survival is highly dependent on the organization, composition, and function of the cell wall. Here, an evaluation of the global A. fumigatus phosphoproteome under cell wall stress caused by the cell wall-damaging agent Congo red (CR) revealed 485 proteins potentially involved in the cell wall damage response. Comparative phosphoproteome analyses with the ΔsakA, ΔmpkC, and ΔsakA ΔmpkC mutant strains from the osmotic stress MAPK cascades identify their additional roles during the cell wall stress response. Our phosphoproteomics allowed the identification of novel kinases and transcription factors (TFs) involved in osmotic stress and in the cell wall integrity (CWI) pathway. Our global phosphoproteome network analysis showed an enrichment for protein kinases, RNA recognition motif domains, and the MAPK signaling pathway. In contrast to the wild-type strain, there is an overall decrease of differentially phosphorylated kinases and phosphatases in ΔsakA, ΔmpkC, and ΔsakA ΔmpkC mutants. We constructed phosphomutants for the phosphorylation sites of several proteins differentially phosphorylated in the wild-type and mutant strains. For all the phosphomutants, there is an increase in the sensitivity to cell wall-damaging agents and a reduction in the MpkA phosphorylation upon CR stress, suggesting these phosphosites could be important for the MpkA modulation and CWI pathway regulation.IMPORTANCE Aspergillus fumigatus is an opportunistic human pathogen causing allergic reactions or systemic infections, such as invasive pulmonary aspergillosis in immunocompromised patients. The mitogen-activated protein kinase (MAPK) signaling pathways are essen

[EN] Osmotic stress signaling in higher plants is crucial to cope with abiotic stress. RAF-like MAPKKKs are activated by hyperosmotic stress and activate downstream ABA-unresponsive and ABA-activated SnRK2s, integrating early osmotic stress and ABA signaling cascades. The connection of B2/B3/B4 RAF-like MAPKKKs with SnRK2s is a new paradigm in signal transduction.

Drought is the most serious environmental challenge that limits plant growth and causes more severe yield losses than other abiotic stress factors resulting in a serious food shortage. Nanomaterials (NMs) are considered as vital tools to overcome contemporary and future challenges in agricultural production. Recently, NMs have been applied for enhancing seed germination, growth, physiology, productivity and quality attributes of various crops under normal or stress conditions. Up to date, there is no a comprehensive review about the potential role of NMs in attenuating the drought-induced adverse effects in crop plants. Thus, this review will highlight this issue. Generally, NMs minimize drought-induced osmotic stress by accumulation of osmolytes that result in osmotic adjustment and improved plant water status. In addition, NMs play a key role to improve root growth, conductive tissue elements and aquaporin proteins facilitating uptake and translocation of water and nutrients. Furthermore, NMs reduce water loss by stomatal closure due to abscisic acid signaling. However, this leads to reduced photosynthesis and oxidative stress damage. At the same time, NMs increase the content of light-harvesting pigments, enzymatic and non-enzymatic antioxidants leading to enhancing photosynthesis with reducing oxidative stress damage. Overall, NMs can ameliorate the deleterious effects of drought stress in crop plants by regulation of gene expression and alternation of various physiological and biochemical processes.

Phytoplankton communities in seasonally ice-covered areas are largely affected by ice algae. The Okhotsk Sea is the southernmost sea ice zone in the northern hemisphere with a sizeable seasonal ice cover, thus ice algae of the Okhotsk sea ice have a large potential to seed the early spring bloom. Little is known about the Okhotsk ice algal communities and their seeding effects. We investigated the dynamics of the composition and the photophysiological performances of an Okhotsk ice algal community in a 6-day laboratory incubation experiment that simulated the natural ice melt conditions. Centric diatoms, especially Thalassiosira spp., overwhelmingly dominated the ice algal community throughout incubation, whereas pennate diatoms, mostly Navicula and Nitzschia, showed little growth with much higher mortality. The maximum photochemical efficiency of Photosystem II (F-v/F-m) was the lowest at the beginning of the ice melt, suggesting a suppressed photosynthetic functioning by changes in salinity. The cellular pigment contents decreased by 30% due to osmotic stress, evidenced by deformed plastids under a microscope. The transcript level of the rbcL gene that encodes the large subunit of RubisCO was significantly higher during ice melt and decreased in the no-ice period, suggesting an urgent need for carbon fixation under the melt condition. Full recovery of photosynthesis and growth was also made after complete ice melt. Our results indicated high seeding potential of Thalassiosira to spring blooms owing to their photophysiological plasticity to dynamic salinity changes.