NaCl Conditions Research Articles

Morphophysiological Responses of Two Chenopodium quinoa Genotypes to Salinity in a Hydroponic System

The Chenopodium quinoa is poised to be a promising species for future food security and combating climate change because of its nutritional content and its halophytic peculiarity. This study focuses on the differential responses of salt-tolerant (Chadmo) and salt-sensitive (Kankolla) under control (CK) and 400 mM sodium chloride (NaCl) in five temporal dimensions (1/2, 1, 3, 6, and 24 h post-treatment time points). Morphological and physiological features assessed include root/shoot dry weight ratio, relative water content (RWC), membrane stability index (MSI), total chlorophyll (CHL), and adaxial and abaxial epidermal bladder cells (EBC). The results indicated a reduction in dry biomass for both genotypes after treatment with Chadmo and Kankolla at 46.96% and 73.07%, respectively. Similarly, a significant reduction in the RWC with Chadmo at 16.69 % and Kankolla at 13.19% was detected. Under 400 mM NaCl condition and CK, Chadmo's average net photosynthetic rate reduced from 15.73±2.97 to 13.02±2.75 µmol CO2 m-1s-1, indicating 17.24% reduction while in the Kankolla, the reduction from was 13.43±4.12 to 8.34±3.16 µmol CO2 m-1s-1 representing 37.92% decline. In addition, this study showed a significant difference (p<0.05) being identified on ANOVA and Tukey analyses in root/shoot dry weight ratio, RWC, membrane stability index (MSI), total chlorophyll (CHL), and adaxial and abaxial epidermal bladder cells (EBC). Those measurement criteria increased by 14.45% and 3.45% in Chadmo and Kankolla, respectively, from the CK to 400 mM NaCl. Using these morpho-physiological responses to salinity, Chadmo proved to be the better-performing genotype when exposed to 400 mM NaCl and hence identified as the salt-tolerant genotype.

Components of the Phenylpropanoid Pathway in the Implementation of the Protective Effect of Sodium Nitroprusside on Wheat under Salinity.

Nitric oxide (NO) is a multifunctional, gaseous signaling molecule implicated in both physiological and protective responses to biotic and abiotic stresses, including salinity. In this work, we studied the effects of 200 µM exogenous sodium nitroprusside (SNP, a donor of NO) on the components of the phenylpropanoid pathway, such as lignin and salicylic acid (SA), and its relationship with wheat seedling growth under normal and salinity (2% NaCl) conditions. It was established that exogenous SNP contributed to the accumulation of endogenous SA and increased the level of transcription of the pathogenesis-related protein 1 (PR1) gene. It was found that endogenous SA played an important role in the growth-stimulating effect of SNP, as evidenced by the growth parameters. In addition, under the influence of SNP, the activation of phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL), and peroxidase (POD), an increase in the level of transcription of the TaPAL and TaPRX genes, and the acceleration of lignin accumulation in the cell walls of roots were revealed. Such an increase in the barrier properties of the cell walls during the period of preadaptation played an important role in protection against salinity stress. Salinity led to significant SA accumulation and lignin deposition in the roots, strong activation of TAL, PAL, and POD, and suppression of seedling growth. Pretreatment with SNP under salinity conditions resulted in additional lignification of the root cell walls, decreased stress-induced endogenous SA generation, and lower PAL, TAL, and POD activities in comparison to untreated stressed plants. Thus, the obtained data suggested that during pretreatment with SNP, phenylpropanoid metabolism was activated (i.e., lignin and SA), which contributed to reducing the negative effects of salinity stress, as evidenced by the improved plant growth parameters.

Comparative analysis of microRNA expression profiles in shoot and root tissues of contrasting rice cultivars (Oryza sativa L.) with different salt stress tolerance.

Rice is the second-most important primary crop in the world and one of the most susceptible crops to salt stress. Soil salinization hinders seedling growth and decreases crop yield by inducing ionic and osmotic imbalances, photosynthesis disturbances, cell wall alterations, and gene expression inhibition. Plants have developed a range of defense mechanisms to adapt to salt stress. One of the most effective means is to make use of plant microRNAs (miRNAs) as post-transcriptional regulators to regulate the expression of developmental genes in order to mitigate the detrimental effects of salt stress. In this study, the miRNA sequencing data between two contrasting rice cultivars, salt-tolerant Doc Phung (DP) and salt-sensitive IR28 seedlings, were compared under control and salt stress (150 mM NaCl) conditions to determine the salt stress-responsive miRNAs. Comparative analysis of miRNA sequencing data detected a total of 69 differentially expressed miRNAs in response to salt stress treatment. Among them, 18 miRNAs from 13 gene families, MIR156, MIR164, MIR167, MIR168, MIR171, MIR396, MIR398, MIR1432, MIR1846, MIR1857, MIR1861, MIR3979, and MIR5508, were identified to be specifically and significantly expressed in the shoot and root tissues of DP seedlings. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses further revealed that these detected miRNAs regulate a range of essential biological and stress response processes, including gene transcription, osmotic homeostasis, root formation, ROS scavenger synthesis, and auxin and abscisic acid signaling pathways. Our findings provide more insight into the miRNA-mediated responsive mechanisms of rice under salt stress and should benefit the improvement of salt stress tolerance in rice.

Asparagine Uptake: a Cellular Strategy of Methylocystis to Combat Severe Salt Stress.

Methylocystis spp. are known to have a low salt tolerance (≤1.0% NaCl). Therefore, we tested various amino acids and other well-known osmolytes for their potential to act as an osmoprotectant under otherwise growth-inhibiting NaCl conditions. Adjustment of the medium to 10 mM asparagine had the greatest osmoprotective effect under severe salinity (1.50% NaCl), leading to partial growth recovery of strain SC2. The intracellular concentration of asparagine increased to 264 ± 57 mM, with a certain portion hydrolyzed to aspartate (4.20 ± 1.41 mM). In addition to general and oxidative stress responses, the uptake of asparagine specifically induced major proteome rearrangements related to the KEGG level 3 categories of "methane metabolism," "pyruvate metabolism," "amino acid turnover," and "cell division." In particular, various proteins involved in cell division (e.g., ChpT, CtrA, PleC, FtsA, FtsH1) and peptidoglycan synthesis showed a positive expression response. Asparagine-derived 13C-carbon was incorporated into nearly all amino acids. Both the exometabolome and the 13C-labeling pattern suggest that in addition to aspartate, the amino acids glutamate, glycine, serine, and alanine, but also pyruvate and malate, were most crucially involved in the osmoprotective effect of asparagine, with glutamate being a major hub between the central carbon and amino acid pathways. In summary, asparagine induced significant proteome rearrangements, leading to major changes in central metabolic pathway activity and the sizes of free amino acid pools. In consequence, asparagine acted, in part, as a carbon source for the growth recovery of strain SC2 under severe salinity. IMPORTANCE Methylocystis spp. play a major role in reducing methane emissions into the atmosphere from methanogenic wetlands. In addition, they contribute to atmospheric methane oxidation in upland soils. Although these bacteria are typical soil inhabitants, Methylocystis spp. are thought to have limited capacity to acclimate to salt stress. This called for a thorough study into potential osmoprotectants, which revealed asparagine as the most promising candidate. Intriguingly, asparagine was taken up quantitatively and acted, at least in part, as an intracellular carbon source under severe salt stress. The effect of asparagine as an osmoprotectant for Methylocystis spp. is an unexpected finding. It may provide Methylocystis spp. with an ecological advantage in wetlands, where these methanotrophs colonize the roots of submerged vascular plants. Collectively, our study offers a new avenue into research on compounds that may increase the resilience of Methylocystis spp. to environmental change.

Dunaliella Ds-26-16 acts as a global regulator to enhance salt tolerance by coordinating multiple responses in Arabidopsis seedlings.

Based on phenotypic, physiological and proteomic analysis, the possible mechanism by which Ds-26-16 regulates salt tolerance in Arabidopsis seedlings was revealed. Functional and mechanistic characterization of salt tolerance genes isolated from natural resources is crucial for their application. In this study, we report the possible mechanism by which Ds-26-16, a gene from Dunaliella, and its point mutation gene EP-5, enhance salt tolerance in Arabidopsis seedlings. Both Ds-26-16 and EP-5 transgenic lines displayed higher seed germination rates, cotyledon-greening rates, soluble sugar contents, decreased relative conductivity and ROS accumulation when germinating under 150 mM NaCl conditions. Comparative proteomic analysis revealed that there were 470 or 391 differentially expressed proteins (DEPs) in Ds-26-16 or EP-5, respectively, compared with the control (3301) under salt stress. The GO and KEGG enrichment analyses showed the DEPs in Ds-26-16 vs. 3301 and EP-5 vs. 3301 were similar and mainly enriched in photosynthesis, regulation of gene expression, carbohydrate metabolism, redox homeostasis, hormonal signal and defense, and regulation of seed germination. Thirty-seven proteins were found to be stably expressed under salt stress due to the expression of Ds-26-16, and eleven of them contain the CCACGT motif which could be bound by the transcription factor in ABA signaling to repress gene transcription. Taken together, we propose that Ds-26-16, as a global regulator, improves salt-tolerance by coordinating stress-induced signal transduction and modulating multiple responses in Arabidopsis seedlings. These results provide valuable information for utilizing natural resources in crop improvement for breeding salt-tolerant crops.

Identificação de genótipos de soja tolerantes a diferentes concentrações de NaCl

Soybean is the main product of Brazilian agriculture, strengthening the country's position as one of the most important commodities in world agricultural trade. However, the salinity present in soils and irrigation waters can hinder the production process and generate economic damage. With the aim of selecting soybean genotypes tolerant to different sodium chloride (NaCl) conditions, 5 soybean genotypes were sown in rolls germitest paper with NaCl solutions at concentrations of 00, 40 and 80 mM. The evaluated characteristics were: final seedling stand, length of root and aerial part of the plant, fresh weight, dry weight of cotyledons, root and aerial part, percentage of germination, index of speed of germination and average time of germination. The design used was completely randomized, in a 3x5 factorial arrangement. The TMG 2383 genotype stood out from the others in the presence of salinity with a greater growth compared to the tested genotypes. The soybean varieties SYN 16861 IPRO, M8644 IPRO, TMG 2383 IPRO and NS8383 RR showed a certain level of resistance to saline stress. The genotypes resistant to saline stress can be used in genetic improvement programs in order to develop new cultivars with greater resistance to saline stress.

The role of cyanoalanine synthase and alternative oxidase in promoting salt stress tolerance in Arabidopsis thaliana

BackgroundCyanide is a toxic chemical that inhibits cellular respiration. In plants, cyanide can be produced by themselves, especially under stressful conditions. Cyanoalanine synthase (CAS) is a key enzyme involved in plant cyanide detoxification. There are three genes encoding CAS in Arabidopsis thaliana, but the roles of these genes in the plant’s response to stress are less studied. In addition, it is known that alternative oxidase (AOX) mediates cyanide-resistant respiration, but the relationship between CAS and AOX in regulating the plant stress response remains largely unknown.ResultsHere, the effects of the overexpression or mutation of these three CAS genes on salt stress tolerance were investigated. The results showed that under normal conditions, the overexpression or mutation of the CAS genes had no significant effect on the seed germination and growth of Arabidopsis thaliana compared with wild type (WT). However, under 50, 100, and 200 mM NaCl conditions, the seeds overexpressing CAS genes showed stronger salt stress resistance, i.e., higher germination speed than WT seeds, especially those that overexpressed the CYS-C1 and CYS-D1 genes. In contrast, the seeds with CAS gene mutations exhibited salt sensitivity, and their germination ability and growth were significantly damaged by 100 and 200 mM NaCl. Importantly, this difference in salt stress resistance became more pronounced in CAS-OE, WT, and mutant seeds with increasing salt concentration. The CAS-OE seeds maintained higher respiration rates than the WT and CAS mutant seeds under salt stress conditions. The cyanide contents in CAS mutant seeds were approximately 3 times higher than those in WT seeds and more than 5 times higher than those in CAS-OE seeds. In comparison, plants overexpressing CYS-C1 had the fastest detoxification of cyanide and the best salt tolerance, followed by those overexpressing CYS-D1 and CYS-D2. Furthermore, less hydrogen sulfide (H2S) was observed in CAS-OE seedlings than in WT seedlings under long-term salt stress conditions. Nonetheless, the lack of AOX impaired CAS-OE-mediated plant salt stress resistance, suggesting that CAS and AOX interact to improve salt tolerance is essential. The results also showed that CAS and AOX contributed to the reduction in oxidative damage by helping maintain relatively high levels of antioxidant enzyme activity.ConclusionIn summary, the findings of the present study suggest that overexpression of Arabidopsis CAS family genes plays a positive role in salt stress tolerance and highlights the contribution of AOX to CAS-mediated plant salt resistance, mainly by reducing cyanide and H2S toxicity.

Multi-ring side groups copolymer as an effective filtration control additive for water-based drilling fluids under high temperature and salt contamination

The control of filtration loss under high temperature and high salinity conditions has been a challenge in drilling fluid industry. In this study, a novel tetra-copolymer with multi-ring side groups was prepared with free radical polymerization as a filtration control additive. The copolymer consisting of N, N-dimethylacrylamide (DMAM) 2-acrylamide-2-methylpropanesulfonic acid (AMPS), N-acryloylmorpholine (ACMO), and sodium p-styrenesulfonate (SSS) was named DAAS. DAAS was analyzed for chemical structure and thermal stability, respectively. The rheological behavior and filtration performance of bentonite-based mud (BM) with DAAS addition was investigated under various temperatures and salt contamination (NaCl) conditions. The effect of DAAS on the dynamical stability of BM was analyzed by a multi-light scattering method. The relationship of DAAS absorption capacity on bentonite surface with concentration, absorption time, temperature and NaCl content was investigated in detail. The effect of DAAS on the chemical group, electrical properties, particle size of bentonite was studied to illuminate the mechanism. Based on the results, the DAAS maintained thermally stable up to 306 °C. DAAS enabled the BM to resist saturated salt contamination after aging at 200 °C with a filtration loss of 7.6 ml. DAAS with multiple ring groups absorbed on the bentonite by forming of hydrogen bond with bentonite. Even under saturated salt and high temperature conditions, the adsorption capacity of DAAS remained at a good level. The dispersion properties of BM were enhanced through decreasing the zeta potential and changing particle size of bentonite. One compact and low permeability filter cake was formed. The filtration loss of BM was finally controlled to a low volume.

Starfish-like particles and nanowires interwoven architecture of CuO for water infiltration–induced electrical device

In the face of sustainable energy development, electricity generation using liquid infiltration in small-sized channels has become one of the effective strategies to optimize energy utilization. As p-type semiconductors, CuO nanomaterials exhibit great potential in energy storage and conversion, which can be used as suitable active materials for constructing nanogenerators. In this study, we proposed CuO water infiltration–induced electrical devices based on starfish-like particles and nanowires (NWs) interwoven architecture. Attributed to the ionovoltaic effect, the electrical signal value is reflected by the difference in carrier concentration between wet and dry regions. Notably, we innovatively used the oxidation–reduction–reoxidation method to control the crystal structure of CuO. In addition, we examined the relationship between CuO microstructure and performance and further explored the effect of different reaction conditions on the device output performance. It was demonstrated that a single device (7.5 cm × 2.5 cm × 18.3 µm) can generate an open-circuit voltage (Voc) of 0.67 V and a short-circuit current (Isc) of 2.49 μA at room temperature when 30 μL of 0.1 mol L−1 NaCl solution permeates from one end of the film. Under a 0.5 mol L−1 NaCl condition (seawater concentration), the device can generate a Voc of 0.82 V and an Isc of 2.70 μA, which is expected to be utilized in the field of sensors for identifying the different concentrations of ions.

SiO2 modified superwetting cotton fabric with anti-crude oil fouling, mechanical stability and corrosion resistance

A superwetting SiO2/PDA/CF membrane was simply fabricated by modifying cotton fabric (CF) with SiO2 and polydopamine (PDA), which exhibits superoleophobicity (i.e., an underwater oil contact angle (UOCA) is 159.7°), and was characterized by TG, SEM, EDS and FTIR. The oil/water separation performance, mechanical stability and corrosion resistance of SiO2/PDA/CF were investigated. The results show that the water fluxes are 34000 and 31300 L·m−2·h−1 for “crude oil/water” and “toluene/water”, respectively. And the oil/water separation efficiencies all are more than 99%. Continuous separation of “crude oil/water” and “toluene/water” for 15 and 100 times, the separation efficiencies are more than 98% and 99%, and the fluxes decrease by 2.9% and 19.7%, respectively. The membrane shows ultra-low adhesion towards crude oil. The as-prepared SiO2/PDA/CF maintains underwater superoleophobicity (i.e., UOCA>150°) after ultrasonically treating for 9 h or 240# sandpaper abrasion for 500 cycles or after exposure to harsh conditions of saturated NaCl, 1 M H2SO4, 1 M NaOH, respectively for 31 days. SiO2/PDA/CF, which is low-cost and environmentally friendly, has good oil/water separation performance, anti-oil fouling, low oil adhesion, mechanical stability, and corrosion resistance, exhibiting great potential applications in solving the serious problem of oily industrial wastewater and oil spills in the ocean.

Tribo- and Tribocorrosion Properties of Magnesium AZ31 Alloy

In automotive and aerospace fields, the use of lightweight materials is required. Magnesium and its alloys combine a low density with high mechanical properties and excellent thermal conductivity. However, those materials suffer from low corrosion and wear resistances. The combined action of corrosion and wear is also critical for these materials. Tribocorrosion of magnesium alloy AZ31 has been investigated with reciprocal sliding wear as a function of the applied load in dry and wet (NaCl) conditions. The study shows that the main wear mechanisms were adhesion, abrasion, and oxidation in dry sliding wear while no adhesion was found in wet sliding wear. Corrosion of the worn surface occurs also in wet sliding wear. It is interesting to notice that wear is less pronounced in wet sliding wear than in dry sliding wear due to the natural lubrication of the NaCl electrolyte. Only severe conditions, high normal load, and wet conditions bring magnesium AZ31 alloy in filiform corrosion.

The Content of Phenolic Compounds in Stevia rebaudiana (Bertoni) Plants Derived from Melatonin and NaCl Treated Seeds.

Stevia is a plant with many beneficial properties. It contains not only steviol glycosides, which are used as non-caloric natural sweeteners, but also a number of metabolites with antioxidant properties. This study examined the content of both phenolic acids and flavonoids in stevia leaves as an effect of treating seeds with melatonin and conducting germination in NaCl conditions. The results of our research indicated higher amounts of phenolic acids compared to flavonoids in stevia leaves. Among these acids, isochlorogenic, rosmarinic, and chlorogenic acids were accumulated in the largest amounts, regardless of the germination conditions. For 5 and 100 µM of melatonin treatments, the content of both phenolic acids and flavonoids increased. However, in salinity conditions (50 mM NaCl), 500 µM of melatonin had the most favorable effect on the synthesis of phenolic acids. The phenolic acids in that case reached a level three-times higher than that in the samples with the same melatonin concentration but without NaCl. We also found that the content of phenolic compounds varied depending on the age of the leaves. To the best of our knowledge, this is the first study to describe the effect of melatonin and NaCl on the synthesis on phenolic acids and flavonoids in stevia.

Effect of salt treatment on the stabilization of Pickering emulsions prepared with rice bran protein

In this study, salt addition (NaCl and CaCl2) was utilized to improve the stability of emulsions formed by rice bran protein (RBP). The result showed that salt addition improved the adsorption of protein on the oil–water interface and enhanced the physical stability of emulsions. Compared to NaCl condition, emulsions with CaCl2 (especially 200 mM) addition exhibited more significant storage stability, as microscopy images showed emulsion structure unchanged and droplet size increasing slightly from 12.02 µm to 16.04 µm in 7 days. It was attributed to the strengthened particle complexation with CaCl2 and the increased hydrophobic interactions, which is explained by the improved particle size (260.93 nm), surface hydrophobicity (1890.10) and fluorescence intensity, thus inducing dense and hardly destroyed interfacial layers. Rheological behavior analyses suggested that salt-induced emulsions had higher viscoelasticity and maintained a stable gel-like structure. The result of study explored the mechanism of salt treated protein particles, developed a further understanding of Pickering emulsion, and was beneficial to the application of RBP.

Metabolomics analysis unveils important changes involved in the salt tolerance of Salicornia europaea.

Salicornia europaea is one of the world's salt-tolerant plant species and is recognized as a model plant for studying the metabolism and molecular mechanisms of halophytes under salinity. To investigate the metabolic responses to salinity stress in S. europaea, this study performed a widely targeted metabolomic analysis after analyzing the physiological characteristics of plants exposed to various NaCl treatments. S. europaea exhibited excellent salt tolerance and could withstand extremely high NaCl concentrations, while lower NaCl conditions (50 and 100 mM) significantly promoted growth by increasing tissue succulence and maintaining a relatively stable K+ concentration. A total of 552 metabolites were detected, 500 of which were differently accumulated, mainly consisting of lipids, organic acids, saccharides, alcohols, amino acids, flavonoids, phenolic acids, and alkaloids. Sucrose, glucose, p-proline, quercetin and its derivatives, and kaempferol derivatives represented core metabolites that are responsive to salinity stress. Glycolysis, flavone and flavonol biosynthesis, and phenylpropanoid biosynthesis were considered as the most important pathways responsible for salt stress response by increasing the osmotic tolerance and antioxidant activities. The high accumulation of some saccharides, flavonoids, and phenolic acids under 50 mM NaCl compared with 300 mM NaCl might contribute to the improved salt tolerance under the 50 mM NaCl treatment. Furthermore, quercetin, quercetin derivatives, and kaempferol derivatives showed varied change patterns in the roots and shoots, while coumaric, caffeic, and ferulic acids increased significantly in the roots, implying that the coping strategies in the shoots and roots varied under salinity stress. These findings lay the foundation for further analysis of the mechanism underlying the response of S. europaea to salinity.

Comparative effects of mineral fertilizer and digestate on growth, antioxidant system, and physiology of lettuce under salt stress

Salt stress in plants presents a major challenge to future agricultural production. Digestate has various effects on plant growth, but little information is available on its effects on the antioxidant system and physiological characteristics of lettuce under salt stress. In this study, the impacts of mineral fertilizer and digestate application on edible parts of lettuce were compared under three salinities. Experimental treatments comprised application of two types of fertilizer (mineral fertilizer and digestate) and three NaCl concentrations (0, 3, and 7.5 dS m− 1). High NaCl concentrations resulted in significantly lower photosynthesis, growth, and physiological indices compared with those under no NaCl addition. However, under the 7.5 dS m− 1 NaCl condition, digestate application (DA) increased the fresh weight (42%), dry weight (27%), photosynthetic pigment contents and photosynthesis (20%) of lettuce compared with that under mineral fertilizer application (MFA). Accumulation of reactive oxygen species was markedly lower, and the membrane stability index was therefore higher, under DA compared with under MFA within the same salinity level. Lipid peroxidation was lower under DA compared with under MFA in all salinity treatments. Salt stress up-regulated the antioxidant system and DA further increased the enzymatic and non-enzymatic antioxidant capability compared with that under MFA. In addition, the total water use was lower and water-related indices, such as water use efficiency of fresh weight, water use efficiency of dry weight and relative water content, were higher under DA compared with under MFA. The application of digestate instead of mineral fertilizer could be a promising practice to alleviate the negative impact of salt stress on the productivity and physiological characteristics of lettuce plants.

Quantitative trait locus mapping and candidate gene analysis for salt tolerance at bud stage in rice.

Soil salinization has a serious influence on rice yield and quality. How to enhance salt tolerance in rice is a topical issue. In this study, 120 recombinant inbred line populations were generated through nonstop multi-generation selfing using a male indica rice variety Huazhan (Oryza sativa L. subsp. indica cv. 'HZ') and a female variety of Nekken2 (Oryza sativa L. subsp. japonica cv. 'Nekken2') as the parents. Germination under 80 mM NaCl conditions was measured and analyzed, and quantitative trait locus (QTL) mapping was completed using a genetic map. A total of 16 salt-tolerance QTL ranges were detected at bud stage in rice, which were situated on chromosomes 3, 4, 6, 8, 9, 10, 11, and 12. The maximum limit of detection was 4.69. Moreover, the qST12.3 was narrowed to a 192 kb region on chromosome 12 using map-based cloning strategy. Statistical analysis of the expression levels of these candidate genes under different NaCl concentrations by qRT-PCR revealed that qST12.3 (LOC_Os12g25200) was significantly down-regulated with increasing NaCl concentration, and the expression level of the chlorine-transporter-encoding gene LOC_Os12g25200 in HZ was significantly higher than that of Nekken2 under 0 mM NaCl. Sequencing analysis of LOC_Os12g25200 promoter region indicated that the gene expression difference between parents may be due to eight base differences in the promoter region. Through QTL mining and analysis, a plurality of candidate genes related to salt tolerance in rice was obtained, and the results showed that LOC_Os12g25200 might negatively regulate salt tolerance in rice. The results provide the basis for further screening and cultivation of salt-tolerant rice varieties and have laid the foundation for elucidating further molecular regulation mechanisms of salt tolerance in rice.

The impact of osmotic stresses on the biofilm formation, immunodetection, and morphology of Aeromonas hydrophila

Aeromonas hydrophila (Ah) is a zoonotic pathogen of great importance to aquaculture and human health. This study systematically evaluated the impact of salinity, sugar, ammonia nitrogen, and nitric nitrogen levels on the fitness of Ah by using Luria-Bertani (LB) broth supplemented with different concentrations of NaCl, sucrose, NH4Cl, urea, NaNO2 or NaNO3. Results showed that the static biofilm formation of Ah was higher at 28 °C compared to 37 °C (P < 0.05). At 28 °C, as the NaCl (>1 %) and sucrose levels increased, the Ah biofilm formation and the binding between Ah cells and monoclonal antibodies (mAbs, for immunodetection) decreased. Elevated ammonia nitrogen and nitric nitrogen levels generated no significant impact on Ah biofilm formation or immunodetection (P > 0.05). The expression of mAbs-targeted Omp remained unchanged under high NaCl or sucrose conditions. Further analysis showed that high sucrose conditions led to the over-expression of the extracellular polysaccharides (PS) and promoted the formation of capsule-like structures. These over-expressed PS and capsule structures might be one reason explaining the inhibited immunodetection efficacy. Results generated from this study provide crucial insights for the design of recovery and detection protocols for Ah present in food or environmental samples.

Actinobacteria as biological nitrogen fixation (BNF) and symbiotic association with actinorhizal plants for restoration of salinized soils

Soil salinity is a significant environmental problem affecting agricultural productivity worldwide. Salinized soils are one of the highest exchangeable sodium salts present in zone of the roots. In this scenario, much focus was drawn towards the symbiotic association between the plant species and the nitrogen fixing actinobacterial species. Actinobacteria are well known for their ability to produce secondary metabolites with potential applications in bioremediation and plant growth promotion. This study investigated the efficiency of co-culturing with actinobacteria to enhance the growth of plants under 0.5% NaCl conditions. Pot trials were conducted with three different treatments, fertile soil without actinobacteria, 0.5% NaCl mixed soil with actinobacteria co-culturing, and 0.5% NaCl mixed soil without actinobacteria co-culturing. The results showed that the plants grown in the 0.5% NaCl mixed soil with actinobacteria co-culturing treatment exhibited significantly plant growth, compared to the other two treatments. The co-culturing of actinobacteria was found to improve the plant's ability to tolerate high salinity conditions and enhance their growth. In this study, actinobacteria were isolated from high saline soil samples using selective media, and their morphological and biochemical characteristics were examined.

New Alkali-tolerant and Halo-tolerant Nocardiopsis Strain B20 from Algerian Saharan Soil: Isolation, Taxonomy, and Antifungal Activity

Abstract A newly characterized actinobacterial strain, designated B20, displayed remarkable tolerance to extreme pH and NaCl conditions, while showcasing a diversity in carbon source utilization. Phylogenetic analysis confirmed its taxonomic assignment within the genus Nocardiopsis. However, several physiological features were found to differentiate B20 from its most closely related Nocardiopsis species. Notably, Nocardiopsis sp. B20 demonstrated potent and selective antifungal activity against various micro-fungi, suggesting its potential as a valuable source for targeted antifungal compounds. Ethyl acetate extract contains a bioactive compound, B20-1, displaying antifungal properties. Chemical revelations indicated the presence of sugars and polycyclic aromatic hydrocarbons (PAHs) in B20-1 compound. The discovery of antifungal PAHs derived from natural sources presents promising opportunity for addressing fungal infections while mitigating environmental concerns and resistance risks associated with synthetic fungicides. However, further research is warranted to evaluate efficacy, assess ecological impacts, and explore potential applications across diverse industries.

Expression of a Salt-Tolerant Pseudolysin in Yeast for Efficient Protein Hydrolysis under High-Salt Conditions.

Protease biocatalysis in a high-salt environment is very attractive for applications in the detergent industry, the production of diagnostic kits, and traditional food fermentation. However, high-salt conditions can reduce protease activity or even inactivate enzymes. Herein, in order to explore new protease sources, we expressed a salt-tolerant pseudolysin of Pseudomonas aeruginosa SWJSS3 isolated from deep-sea mud in Saccharomyces cerevisiae. After optimizing the concentration of ion cofactors in yeast peptone dextrose (YPD) medium, the proteolytic activity in the supernatant was 2.41 times more than that in the control group when supplemented with 5 mM CaCl2 and 0.4 mM ZnCl2. The extracellular proteolytic activity of pseudolysin reached 258.95 U/mL with optimized expression cassettes. In addition, the S. cerevisiae expression system increased the salt tolerance of pseudolysin to sodium chloride (NaCl)and sodium dodecyl sulfate (SDS) and the recombinant pseudolysin retained 15.19% activity when stored in 3 M NaCl for 7 days. The recombinant pseudolysin was able to efficiently degrade the β-conglycinin from low-denatured soy protein isolates and glycinin from high-denatured soy protein isolates under high temperatures (60 °C) and high-salt (3 M NaCl) conditions. Our study provides a salt-tolerant recombinant protease with promising applications in protein hydrolysis under high-salt conditions.