Reaumuria trigyna is an endangered small shrub endemic to desert regions in Inner Mongolia. This dicotyledonous recretohalophyte has unique morphological characteristics that allow it to tolerate the ...stress imposed by semi-desert saline soil. However, it is impossible to explore the mechanisms underlying this tolerance without detailed genomic information. Fortunately, newly developed high-throughput sequencing technologies are powerful tools for de novo sequencing to gain such information for this species.
Two sequencing libraries prepared from control (C21) and NaCl-treated samples (T43) were sequenced using short reads sequencing technology (Illumina) to investigate changes in the R. trigyna transcriptome in response to salt stress. Among 65340 unigenes, 35495 (52.27%) were annotated with gene descriptions, conserved domains, gene ontology terms, and metabolic pathways with a cut-off E-value of 10-5. These included 44 Gene Ontology (GO) terms, 119 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and 25 Clusters of Orthologous Groups families. By comparing the transcriptomes from control and NaCl-treated plants, 5032 genes showed significantly differences in transcript abundance under salt stress (false discovery rate ≤ 0.001 and |log2Ratio| ≥ 1). These genes were significantly enriched in 29 KEGG pathways and 26 GO terms. The transcription profiles indicated that genes related to ion transport and the reactive oxygen species scavenging system were relevant to the morphological and physiological characteristics of this species. The expression patterns of 30 randomly selected genes resulted from quantitative real-time PCR were basically consistent with their transcript abundance changes identified by RNA-seq.
The present study identified potential genes involved in salt tolerance of R. trigyna. The globally sequenced genes covered a considerable proportion of the R. trigyna transcriptome. These data represent a genetic resource for the discovery of genes related to salt tolerance in this species, and may be a useful source of reference sequences for closely related taxa. These results can also further our understanding of salt tolerance in other halophytes surviving under sodic stress.
Next-generation nuclear reactor concepts and advanced techniques for reprocessing spent nuclear fuel (SNF) are drawing great attention in the nuclear field. Molten halide salts have been proposed as ...the fuel solvent and coolants for many molten salt reactor (MSR) concepts, and the electrolyte for the electrochemical separation of the SNF. The major concern of using molten salts is the corrosion of the structural materials imposed by these extreme environments. Materials corrosion is more challenging in the molten salt nuclear systems than in the traditional water reactors as the formation of the passivating oxide layer on the corrosion resistant alloys becomes thermodynamically unfavorable in molten salts and the use of many corrosion resistant alloys is restricted. This review takes a comprehensive approach covering all relevant work in the field: corrosion data accumulated since the 1950s to date, major corrosion problems and corresponding mechanisms, metallurgical factors, historical development of corrosion resistant alloys and recent attempts. The key environmental factors influencing corrosion in various nuclear systems, electrode kinetics, thermodynamic properties, and corrosion prevention techniques are also reviewed. Finally, current progress and challenges are summarized with an attempt at identifying knowledge gaps and future research directions.
Summary
Bile salts are the water‐soluble end products of hepatic cholesterol catabolism that are released into the duodenum and solubilize lipids due to their amphipathic structure. Bile salts also ...act as endogenous ligands for dedicated nuclear receptors that exert a plethora of biological processes, mostly related to metabolism. Bile salts are actively reclaimed in the distal part of the small intestine, released into the portal system, and subsequently extracted by the liver. This enterohepatic cycle is critically dependent on dedicated bile salt transporters. In the intestinal lumen, bile salts exert direct antimicrobial activity based on their detergent property and shape the gut microbiota. Bile salt metabolism by gut microbiota serves as a mechanism to counteract this toxicity and generates bile salt species that are distinct from those of the host. Innate immune cells of the liver play an important role in the early recognition and effector response to invading microbes. Bile salts signal primarily via the membrane receptor TGR5 and the intracellular farnesoid‐x receptor, both present in innate immune cells. In this review, the interactions between bile salts, gut microbiota, and hepatic innate immunity are discussed.
Underground salt caverns are used globally for large-scale energy storage. In the thinly bedded rock salt in China, two butted-well horizontal (TWH) caverns, as alternatives for energy storage, are ...regarded as having better suitability and economy than vertical caverns. However, understandings of the cavern shape development and control methods of TWH-caverns remain insufficient. To overcome these shortcomings with respect to TWH-caverns, we conducted physical simulations of TWH-cavern construction using a high strength steel mold and molded large rock salt specimens. We established a platform for physical simulation of TWH-cavern water-solution construction using the large molded rock salt specimens, so that the construction process is visible and easily observed. Six groups of physical simulations of TWH-cavern construction were designed and implemented. The variables which affect the cavern outline expansion were investigated and compared, including water injection rate, transferring of injection well, oil blanket, and retreating position of the water outlet. Finally the expansion rules of the cavern outline, and different effects when injecting from an inclined well vs. From a vertical well were explored, as well as an attempt of retreating water outlet. This study provides significant guidance for constructing horizontal caverns for energy storage in thinly bedded rock salt.
•Physical simulations of TWHH-cavern were made by using large molded rock salt.•Salt solution mainly appears in the regions where the water outlet is adjacent.•Change to inject water from vertical well can promote to dissolve horizontal region.•Retreating the outlet position is effective to form large and safety TWH-caverns.•TWH-caverns are desirable option for large-scale energy storage in bedded rock salts.
Halophytes are defined as plants that are adapted to live in soils containing high concentrations of salt and benefiting from it, and thus represent an ideal model to understand complex physiological ...and genetic mechanisms of salinity stress tolerance. It is also known that oxidative stress signalling and reactive oxygen species (ROS) detoxification are both essential components of salinity stress tolerance mechanisms. This paper comprehensively reviews the differences in ROS homeostasis between halophytes and glycophytes in an attempt to answer the questions of whether stress-induced ROS production is similar between halophytes and glycophytes; is the superior salinity tolerance in halophytes attributed to higher antioxidant activity; and is there something special about the specific ‘pool’ of enzymatic and non-enzymatic antioxidants in halophytes. We argue that truly salt-tolerant species possessing efficient mechanisms for Na+ exclusion from the cytosol may not require a high level of antioxidant activity, as they simply do not allow excessive ROS production in the first instance. We also suggest that H2O2 ‘signatures’ may operate in plant signalling networks, in addition to well-known cytosolic calcium ‘signatures’. According to the suggested concept, the intrinsically higher superoxide dismutase (SOD) levels in halophytes are required for rapid induction of the H2O2 ‘signature’, and to trigger a cascade of adaptive responses (both genetic and physiological), while the role of other enzymatic antioxidants may be in decreasing the basal levels of H2O2, once the signalling has been processed. Finally, we emphasize the importance of non-enzymatic antioxidants as the only effective means to prevent detrimental effects of hydroxyl radicals on cellular structures.
sp. SA187 is a root endophytic bacterium that maintains growth and yield of plants under abiotic stress conditions. In this work, we compared the metabolic wirings of Arabidopsis and SA187 in the ...free-living and endophytic interaction states. The interaction of SA187 with Arabidopsis induced massive changes in bacterial gene expression for chemotaxis, flagellar biosynthesis, quorum sensing, and biofilm formation. Besides modification of the bacterial carbon and energy metabolism, various nutrient and metabolite transporters and the entire sulfur pathway were up-regulated. Under salt stress, Arabidopsis resembled plants under sulfate starvation but not when colonized by SA187, which reprogramed the sulfur regulon of Arabidopsis. In accordance, salt hypersensitivity of multiple Arabidopsis sulfur metabolism mutants was partially or completely rescued by SA187 as much as by the addition of sulfate, L-cysteine, or L-methionine. Many components of the sulfur metabolism that are localized in the chloroplast were partially rescued by SA187. Finally, salt-induced accumulation of reactive oxygen species as well as the hypersensitivity of LSU mutants were suppressed by SA187. LSUs encode a central regulator linking sulfur metabolism to chloroplast superoxide dismutase activity. The coordinated regulation of the sulfur metabolic pathways in both the beneficial microorganism and the host plant is required for salt stress tolerance in Arabidopsis and might be a common mechanism utilized by different beneficial microbes to mitigate the harmful effects of different abiotic stresses on plants.
Protein kinases play an important role in regulating the response to abiotic stress in plant. CIPKs are plant‐specific signal transducers, and some members have been identified. However, the precise ...functions of novel CIPKs still remain unknown. Here we report that HbCIPK2 is a positive regulator of salt and osmotic stress tolerance. HbCIPK2 was screened out of the differentially expressed fragments from halophyte Hordeum brevisubulatum by cDNA‐AFLP technique, and was a single‐copy gene without intron. Expression of HbCIPK2 was increased by salt, drought and ABA treatment. HbCIPK2 is mainly localized to the plasma membrane and nucleus. Ectopic expression of 35S:HbCIPK2 not only rescued the salt hypersensitivity in Arabidopsis mutant sos2‐1, but also enhanced salt tolerance in Arabidopsis wild type, and exhibited tolerance to osmotic stress during germination. The HbCIPK2 contributed to the ability to prevent K+ loss in root and to accumulate less Na+ in shoot resulting in K+/Na+ homeostasis and protection of root cell from death, which is consistent with the gene expression profile of HbCIPK2‐overexpressing lines. These findings imply possible novel HbCIPK2‐mediated salt signalling pathways or networks in H. brevisubulatum.
Corrosion studies in molten fluoride and chloride salts were surveyed, and key data were aggregated into a single dataset. Studies were graphed by salt purity, temperature, sample material, container ...material, and experimental method (loop, capsule, crucible). To elucidate and quantify the factors that affect corrosion in molten salts, a data analysis using a newly-defined corrosion resistance score and a correlation analysis using techniques borrowed from machine learning were performed. It is shown that salt purity had the strongest correlation with corrosion rates in molten chlorides and fluorides. Data analysis across varied works was inconsistent due to the lack of standardization among molten salt corrosion studies.
•Corrosion studies in fluoride and chloride salts from 1960 to 2016 are aggregated into a single dataset.•Corrosion testing techniques and reviewed.•Attributes of each study are processed and graphed to elucidate how they affect corrosion rates.•A data analysis is performed to show how important factors correlate with corrosion in molten salts.
Switching regular salt (sodium chloride) to salt enriched with potassium chloride (25 % potassium chloride, 75 % sodium chloride) has been shown to reduce blood pressure and the risk of ...cardiovascular diseases. We sought to define the potential for the current production of sodium chloride and potassium chloride to support a global switch to the use of potassium-enriched salt.
We summarised data from geological surveys, government reports and trade organisations describing the global production and supply of sodium chloride and potash (the primary source of potassium chloride) and compared this to potential requirements for potassium-enriched salt.
Global.
Not applicable.
Approximately 280 million tonnes of sodium chloride were produced in 2020 with China and the USA the main producers. Global production of potash from which potassium chloride is extracted was about forty-four million tonnes with Canada, Belarus, Russia and China providing 77 % of the world's supply. There were forty-eight countries in which potassium-enriched salt is currently marketed with seventy-nine different brands identified. Allowing for loss of salt between manufacture and consumption, a full global switch from regular salt to potassium-enriched salt would require about 9·7 million tonnes of sodium chloride to be replaced with 9·7 million tonnes of potassium chloride annually.
Significant upscaling of the production of potassium chloride and the capacity of companies able to manufacture potassium-enriched salt, as well as a robust business case for the switch to potassium chloride, would be required.
Abiotic stresses, such as soil salinity and drought, negatively affect growth, development, and yield in cotton. Gene ABP9, which encodes a bZIP transcription factor, binds to the abscisic acid ...(ABA)-responsive-element (ABRE2) motif of the maize catalase1 gene. Its expression significantly improves tolerance in Arabidopsis to multiple abiotic stresses, but little is known about its role in cotton. In the present study, the ABP9 gene was introduced into upland cotton (Gossypium hirsutum L.) cultivar R15 by agrobacterium tumefaciens-mediated transformation, and 12 independent transgenic cotton lines were obtained. Cotton plants over-expressing ABP9 have enhanced tolerance to salt and osmotic stress. Under stress, they developed better root systems in a greenhouse and higher germination, reduced stomatal aperture, and stomatal density in a growth chamber. Under drought conditions, survival rate and relative water content (RWC) of transgenic cotton were higher than those of R15 plants. Under salt and osmotic stresses, chlorophyll, proline, and soluble sugar contents significantly increased in transgenic cotton leaves and the malondialdehyde (MDA) content was lower than in R15. Overexpression of ABP9 also enhanced oxidative stress tolerance, reduced cellular levels of reactive oxygen species (ROS) through increased activities of antioxidative enzymes, and alleviated oxidative damage to cell. Interestingly, ABP9 over-expressing cotton was more sensitive to exogenous ABA than R15 at seed germination, root growth, stomatal aperture, and stomatal density. Moreover, ABP9 overexpression upregulated significantly the transcription levels of stress-related genes such as GhDBP2, GhNCED2, GhZFP1, GhERF1, GhHB1, and GhSAP1 under salt treatment. Conjointly, these results showed that overexpression of ABP9 conferred enhanced tolerance to multiple abiotic stresses in cotton. The stresstolerant transgenic lines provide valuable resources for cotton breeding.
PDF
