Toxic Ions Research Articles

Comparative Physiological and Gene Expression Analyses Reveal Mechanisms Involved in Maintaining Photosynthesis Capacity, Alleviating Ion Toxicity and Oxidative Stress of Kentucky Bluegrass under NaCl Treatment.

Kentucky bluegrass (Poa pratensis L.), a widely used cool-season turfgrass, shows a high sensitivity to soil salinity. Clarifying the adaptative mechanisms of Kentucky bluegrass that serve to improve its salt tolerance in saline environments is urgent for the application of this turfgrass in salt-affected regions. In this study, physiological responses of the Kentucky bluegrass cultivars "Explorer" and "Blue Best" to NaCl treatment, as well as gene expressions related to photosynthesis, ion transport, and ROS degradation, were analyzed. The results showed that the growth of "Explorer" was obviously better compared to "Blue Best" under 400 mM NaCl treatment. "Explorer" exhibited a much stronger photosynthetic capacity than "Blue Best" under NaCl treatment, and the expression of key genes involved in chlorophyll biosynthesis, photosystem II, and the Calvin cycle in "Explorer" was greatly induced by salt treatment. Compared with "Blue Best", "Explorer" could effectively maintain Na+/K+ homeostasis in its leaves under NaCl treatment, which can be attributed to upregulated expression of genes, such as HKT1;5, HAK5, and SKOR. The relative membrane permeability and contents of O2- and H2O2 in "Explorer" were significantly lower than those in "Blue Best" under NaCl treatment, and, correspondingly, the activities of SOD and POD in the former were significantly higher than in the latter. Moreover, the expression of genes involved in the biosynthesis of enzymes in the ROS-scavenging system of "Explorer" was immediately upregulated after NaCl treatment. Additionally, free proline and betaine are important organic osmolytes for maintaining hydration status in Kentucky bluegrass under NaCl treatment, as the contents of these metabolites in "Explorer" were significantly higher than in "Blue Best". This work lays a theoretical basis for the improvement of salt tolerance in Kentucky bluegrass.

Tolerance Mechanisms of Olive Tree (Olea europaea) under Saline Conditions.

The olive tree (Olea europaea L.) is an evergreen tree that occupies 19% of the woody crop area and is cultivated in 67 countries on five continents. The largest olive production region is concentrated in the Mediterranean basin, where the olive tree has had an enormous economic, cultural, and environmental impact since the 7th century BC. In the Mediterranean region, salinity stands out as one of the main abiotic stress factors significantly affecting agricultural production. Moreover, climate change is expected to lead to increased salinization in this region, threatening olive productivity. Salt stress causes combined damage by osmotic stress and ionic toxicity, restricting olive growth and interfering with multiple metabolic processes. A large variability in salinity tolerance among olive cultivars has been described. This paper aims to synthesize information from the published literature on olive adaptations to salt stress and its importance in salinity tolerance. The morphological, physiological, biochemical, and molecular mechanisms of olive tolerance to salt stress are reviewed.

Mixed-matrix membrane designed with water channels and sieving effect for effective removal of heavy metals

The challenge of eliminating heavy metal ions from water has been addressed using Polysulfone (PSf) membranes, which have demonstrated significant potential in treating contaminated solutions. This research aimed to improve the permeability and separation performance of PSf membranes by incorporating Al2SiO6 into their structure. The introduction of Al2SiO6 into the membrane matrix was achieved through the nonsolvent-induced phase separation (NIPS). The resulting mixed-matrix membrane (MMM) exhibited improved efficiency in water filtration. The inclusion of Al2SiO6 led to desirable changes in membrane properties such as hydrophilicity, contact angle and porosity, thereby enhancing the performance of heavy metal ion removal capability. Under a pressure of 2 bar, the mixed matrix membranes achieved rejections exceeding 95 % for lead and 70 % for arsenic. Furthermore, the occurrence of Al2SiO6 enhanced the anti-fouling assets of the PSf membrane by increasing its hydrophilic nature and facilitating the development of a hydration layer, which tends to prevent the interactions between the membrane surface and foulant. These properties make these membranes suitable candidates for separating toxic ions from water.

Sustainable Strategy to Boost Legume Growth under Salinity and Drought Stress in Semi-Arid and Arid Regions

The escalating risks of drought and salinization due to climate change and anthropogenic activities are a major global concern. Rhizobium–legume (herb or tree) symbiosis is proposed as an ideal solution for improving soil fertility and rehabilitating arid lands, representing a crucial direction for future research. Consequently, several studies have focused on enhancing legume tolerance to drought and salinity stresses using various techniques, including molecular-based approaches. These methods, however, are costly, time-consuming, and cause some environmental issues. The multiplicity of beneficial effects of soil microorganisms, particularly plant growth-promoting bacteria (PGPB) or plant-associated microbiomes, can play a crucial role in enhancing legume performance and productivity under harsh environmental conditions in arid zones. PGPB can act directly or indirectly through advanced mechanisms to increase plant water uptake, reduce ion toxicity, and induce plant resilience to osmotic and oxidative stress. For example, rhizobia in symbiosis with legumes can enhance legume growth not only by fixing nitrogen but also by solubilizing phosphates and producing phytohormones, among other mechanisms. This underscores the need to further strengthen research and its application in modern agriculture. In this review, we provide a comprehensive description of the challenges faced by nitrogen-fixing leguminous plants in arid and semi-arid environments, particularly drought and salinity. We highlight the potential benefits of legume–rhizobium symbiosis combined with other PGPB to establish more sustainable agricultural practices in these regions using legume–rhizobium–PGPB partnerships.

Dietary supplementation with glutamate enhanced antioxidant capacity, ammonia detoxification and ion regulation ability in Nile tilapia (Oreochromis niloticus) exposed to acute alkalinity stress

Saline-alkali aquaculture is an important way to improve the comprehensive utilization capacity of alkaline water and alleviate the fresh water crisis. This study investigated the effects of dietary L-glutamate (Glu) on ion regulation, ammonia detoxification and antioxidant capacity in Nile tilapia (Oreochromis niloticus) exposed to acute carbonate alkalinity stress. A total of 270 fish (6.06 ± 0.12 g) were fed three different dietary Glu supplements 0%, 1.5%, and 3.0% for 45 days. After the feeding trial, the fish were exposed to fresh water (control) or 53.57 mmol/l carbonate alkaline water for 24 h. The results showed that dietary Glu not only improved the weight gain and condition factors of tilapia but also promoted three reactions in which ammonia was converted into nontoxic substrates. After 24 h of alkalinity stress, tilapia fed a 15 g/kg Glu-supplement diet had considerably higher ion transport capacity in their gills compared to the control group (p < 0.05). Moreover, the gill structure of tilapia in the 15 g/kg Glu-supplement group was intact, while the structures in the other groups were impaired. Dietary Glu supplementation (15 g/kg) significantly increased the expression of genes related to urea and glutamine (Gln) synthesis. Additionally, the ammonia excretion capacity and antioxidant capacity were greatest in tilapia in the 15 g/kg Glu-supplement group (p < 0.05). These results indicated that in addition to promoting the growth of Nile tilapia, dietary Glu supplementation ameliorate the alkalinity tolerance of Nile tilapia and prevent oxidative damage, ionic toxicity and ammonia poisoning caused by acute carbonate alkalinity stress.

Combined clinical, structural, and cellular studies discriminate pathogenic and benign TRPV4 variants.

Dominant mutations in the calcium-permeable ion channel TRPV4 (transient receptor potential vanilloid 4) cause diverse and largely distinct channelopathies, including inherited forms of neuromuscular disease, skeletal dysplasias, and arthropathy. Pathogenic TRPV4 mutations cause gain of ion channel function and toxicity that can be rescued by small molecule TRPV4 antagonists in cellular and animal models, suggesting that TRPV4 antagonism could be therapeutic for patients. Numerous variants in TRPV4 have been detected with targeted and whole exome/genome sequencing, but for the vast majority, their pathogenicity remains unclear. Here, we used a combination of clinical information and experimental structure-function analyses to evaluate 30 TRPV4 variants across various functional protein domains. We report clinical features of seven patients with TRPV4 variants of unknown significance and provide extensive functional characterization of these and an additional 17 variants, including structural position, ion channel function, subcellular localization, expression level, cytotoxicity, and protein-protein interactions. We find that gain-of-function mutations within the TRPV4 intracellular ankyrin repeat domain target charged amino acid residues important for RhoA interaction, whereas ankyrin repeat domain residues outside of the RhoA interface have normal or reduced ion channel activity. We further identify a cluster of gain-of-function variants within the intracellular intrinsically disordered region that may cause toxicity via altered interactions with membrane lipids. In contrast, assessed variants in the transmembrane domain and other regions of the intrinsically disordered region do not cause gain of function and are likely benign. Clinical features associated with gain of function and cytotoxicity include congenital onset of disease, vocal cord weakness, and motor predominant disease, whereas patients with likely benign variants often demonstrated late-onset and sensory-predominant disease. These results provide a framework for assessing additional TRPV4 variants with respect to likely pathogenicity, which will yield critical information to inform patient selection for future clinical trials for TRPV4 channelopathies.

Silver peroxide-incorporated carbon dots with high photothermal performance for combating bacteria

The widespread use of antibiotics often increases bacterial resistance. Herein, we reported a silver peroxide-incorporated carbon dots (defined as Ag2O2–CDs) with high photothermal conversion efficiency via in situ oxidation process. The prepared Ag2O2–CDs exhibited ultra-small size of 2.0 nm and hybrid phase structure. Meanwhile, the Ag2O2–CDs were of a similar optical performance comparing with traditional carbon dots (CDs). Importantly, the incorporation of Ag2O2 into CDs significantly enhanced photothermal conversion efficiency from 3.8% to 28.5%. By combining silver ion toxicity and photothermal ablation, the Ag2O2–CDs were capable of destroying gram-positive and gram-negative bacterium effectively. These findings demonstrated that the Ag2O2–CDs could be served as a potential antibacterial agent for clinical applications.

Mechanistic Innovations in Fluorescent Chemosensors for Detecting Toxic Ions: PET, ICT, ESIPT, FRET and AIE Approaches.

Fluorescent chemosensors have become vital tools for detecting toxic ions due to their exceptional sensitivity, selectivity, and rapid response times. These sensors function through various mechanisms, each providing unique advantages for specific applications. This review offers a comprehensive overview of the mechanistic innovations in fluorescent chemosensors, emphasizing five key approaches: Photoinduced Electron Transfer (PET), Fluorescence Resonance Energy Transfer (FRET), Intramolecular Charge Transfer (ICT), Aggregation-Induced Emission (AIE), and Excited-State Intramolecular Proton Transfer (ESIPT). We highlight the substantial progress made in developing these chemosensors, discussing their design principles, sensing mechanisms, and practical applications, with a particular focus on their use in detecting toxic ions relevant to environmental and biological contexts.

Determination of the Localized Surface Plasmon Resonance Alteration of AgNPs via Multiwavelength Evanescent Scattering Microscopy for Pb(II) Detection.

We developed multiwavelength evanescent scattering microscopy (MWESM), which can acquire plasmonic nanoparticle images at the particle level using the evanescent field as the incident source and distinguish different LSPR (localized surface plasmon resonance) spectral peaks among four wavelengths. Our microscope could be easily and simply built by modifying a commercial total internal reflection fluorescence microscope (TIRFM) with the substitution of a beamsplitter and the addition of a semicircular stop. The ultrathin depth of illumination and rejection of the reflected incident source together contribute to the high sensitivity and contrast of single nanoparticle imaging. We first validated the capability of our imaging system in distinguishing plasmonic nanoparticles bearing different LSPR spectral peaks, and the results were consistent with the scattering spectra results of hyperspectral imaging. Moreover, we demonstrated high imaging quality from the aspects of the signal/noise ratio and point spread function of the single-particle images. Meaningfully, the system can be utilized in rapidly determining the concentration of toxic lead ions in environmental and biological samples with good linearity and sensitivity, based on single-particle evanescent scattering imaging through the detection of the alteration of the LSPR of silver nanoparticles. This system holds the potential to advance the field of nanoparticle imaging and foster the application of nanomaterials as sensors.

Benzothiazole-Quinoline-Based Fluorescent Probe for Fe3+ and its Applications in Environmental and Biological Samples.

Due to the its high abundance, iron ion contamination and toxicity is one of the most challenging issue for living beings. Although, iron is extremenly important for several body functions, excess amount of iron in the body can also be fatal. In last century, rapid industrialization, iron extraction and mismanagement of industrial waste disposal leads to iron contamination in water bodies. Therefore, versatile iron sensors needs to be develop which can be employed for detection in biological as well as real water samples. 8-hydroxyquinoline is well-known for its strong affinity towards transition metals including Fe3+. In this regard, we have synthesised benzothiazole-quinoline derived 1,2,3- triazole (4HBTHQTz), in which 4-(benzo[d]thiazol-2-yl)phenolic (4-HBT) group acts as a fluorophore. 4HBTHQTz showed high fluorescence and induced a selective decrease in fluorescence with Fe3+ at 380nm (λex. = 320nm). The detection limit of 4HBTHQTz with Fe3+ is calculated as 0.64μM, which is lower than the WHO recommended limit in drinking water. 4HBTHQTz works over the 5-8 pH range and has shown promising results for quantitative detection of Fe3+ in water samples collected from tap, river and seawater. 4HBTHQTz can also detect the Fe3+ in biological samples which is confirmed by fluorescence cell imaging using L929 mouse fibroblast cells. Overall, 4HBTHQTz showed advantages such as high selectivity, quick detection, and good limit of detection (LOD) for Fe3+.

A Review of Nanotechnology-Enabled Fluorescent Chemosensors for Environmental Toxic Ion Detection

A Review of Nanotechnology-Enabled Fluorescent Chemosensors for Environmental Toxic Ion Detection

STRATEGIES OF TOXIC CHROMIUM (VI) MITIGATION FROM TANNERY EFFLUENTS: A REVIEW

Hexavalent chromium i.e., Cr (VI) is highly toxic and carcinogenic it enters the environment through several anthropogenic activities. It is spuriously used in various industrial operations (leather tanning, electroplating, paint and pigment production etc.) because of its hardness and stability. It is found in industrial effluents in concentrations much above the prescribed limit of the World Health Organization (50 µg/L). Detection and remediation of chromium has been the subject of research of many scientists but many previous review works have been insufficient in comprehensive information. This review conveys the basic knowledge of chromate toxicity leading to physical discomfort and sometimes life-threatening illness including irreversible damage to the vital body system in humans. Conventional methods for removing toxic chromium ions (by chemical reduction followed by precipitation, ion- exchange and adsorption on activated coal, alum, kaolinite and ash) are costly for large-scale treatment. Microbial uptake followed by reduction of toxic Cr (VI) has become very successful due to its cost-effectiveness and use as a non-toxic agent. This is referred to as bioremediation. This review emphasises various strategies for hexavalent chromium bioremediation from contaminated water. This review article, therefore, tries to highlight this aspect of bioremediation of Cr (VI) from industrial effluents by native, indigenously resident chromate-resistant bacteria.

Integrated physiological and molecular approaches to study salt-induced adaptation in halophytes collected from extremely saline lands

Diverse halophytes were collected across the extremely salt-affected lands of Haryana to explore their salt potential. Higher levels of Na+ and Cl- were observed in leaves (3.20 and 4.55%) than in stem (0.78 and 1.09%) and root (0.81 and 0.80 %). Interestingly, these plants also accumulated higher concentrations of K+ for their survival. Similarly, Ca2+ accumulation was higher in leaves (1.57%) than in stems (1.15%) and roots (1.18%). The salt tolerance potential of these halophytes was assessed by examining the ratio of accumulation of toxic ions, namely Na/K, Na/Ca, and Na+Cl to K+Ca, resulting in their characterization and ranking from highly salt tolerant to least tolerant. The utilization of this ionic accumulation index has the potential to serve as a criterion for the elimination of surplus toxic ions from soil. The halophytes employed adaptive mechanisms by synthesizing osmolytes, such as proline, soluble sugars, and soluble proteins, in both leaves and roots. The upregulation of genes P5CS and NHX1, responsible for proline synthesis and membrane transportation, further confirmed the halophytes’ ability to tolerate high salinity. The findings of these studies indicated the potential for domesticating salt-tolerant halophytes in salt-affected soils.

MaMYBR30, a Novel 1R-MYB, Plays Important Roles in Plant Development and Abiotic Stress Resistance.

The V-myb myeloblastosis viral oncogene homolog (MYB) family participate in various bioprocesses including development and abiotic stress responses. In the present study, we first report a 1R SHAQKYF-class MYB, MaMYBR30, in mulberry. Subcellular localization and sequence analysis indicated MaMYBR30 is located in the nucleus and belongs to a CCA-like subgroup with a conserved SHAQKYF motif. Expression profile analysis showed that MaMYBR30 is expressed in leaves and can be induced by drought and salt stress. The down-regulation of MaMYBR30 using virus-induced gene silence (VIGS) in mulberry and the overexpression of MaMYBR30 in Arabidopsis were induced to explore the function of MaMYBR30. The functional characterization of MaMYBR30 in vivo indicated that MaMYBR30 can positively regulate the resistance of mulberry to drought while negatively regulating the resistance of mulberry to salt stress. In addition, MaMYBR30 also affects flower development and reproductive growth, especially after exposure to salt stress. Weighted gene co-expression network analysis (WGCNA) primarily revealed the possible genes and signal pathways that are regulated by MaMYBR30. Our results also imply that complex molecular mechanisms mediated by MaMYBR30, including crosstalk of ion toxicity, phytohormone signal transduction, flowering development, and epigenetic modification, need to be further explored in the future.

Enhancement of root abscisic acid mediated osmotic regulation by macroalgal compounds promotes adaptability of rice (Oryza sativa L.) in response to progressive metal ion mediated environmental stress

Soil deterioration is a major cause of poor agricultural productivity, necessitating sufficient nutrient inputs like fertilizers and amendments for sustainable use. As one such strategy, the current study evaluates the potential of Sargassum wightii, a brown seaweed extract, as an osmopriming agent to improve seed germination, early establishment, and competent seedling performances in acidic soil. The elemental makeup of seaweed extract (BS) showed that it included major plant macro (Potassium, Nitrogen and Phosphorous), as well as micronutrients (Magnesium and Iron) and trace elements (Zinc, Copper, and Molybdenum). While seed germination was impacted by H+ ion toxicity, seeds primed with BS emerged earlier and showed a higher germination percentage (98.2%) and energy (92.4%). BS treatments enhanced seedling growth by 63% and had a positive effect on root growth (68.2%) as well as increases in root surface area (10%) and volume (67.01%). Stressed seedlings had 76.39% and 63.2% less carotenoid and chlorophyll, respectively. In seedlings treated with BS, an increase in protein and Total Soluble Sugars content of 14.56 and 7.19%, respectively, was seen. Fourier Transform-Infra Red analysis of postharvest soil indicated improved soil health with absorbance corresponding to enhanced soil water holding capacity and organic matter. Increased abscisic acid synthesis rate and associated antioxidant enzyme system (Malondialdehyde, Glutathione peroxidases and ascorbate peroxidase) activation, along with enhanced H+ adenosine triphosphate-ase and glutathione activities, help ameliorate and deport H+ ions from cells, scavenge Reactive Oxygen Species, thus protecting cells from injury. Seaweed extract successfully reduced H+-induced ion toxicities in rice by promoting their germination, physiological, metabolically, and growth parameters that could ultimately increase their productivity and yield in a sustainable and environmentally friendly manner.

The development of an efficient precipitation-flotation-dewatering (PFD) process for acid mine drainage treatment

Acid mine drainage (AMD) stands as a prevalent environmental challenge across numerous mining sites, often addressed through the high-density sludge (HDS) process, a typical neutralization and sedimentation process. However, despite its widespread use, the HDS process requires prolonged treatment durations and presents challenges in sludge dewatering and site relocation, thus falling short of an optimal solution. In this study, an efficient precipitation-flotation-dewatering (PFD) process was developed and optimized as a viable alternative to the HDS process, offering efficient AMD treatment. The experimental results indicate that over 90 % of ions were successfully precipitated by employing CaO as a neutralizing agent to adjust AMD pH to 10.0. Flotation was then conducted with a low-profile flotation column after adding an optimal concentration of 10 mg/L of A-100 flocculant and 400 mg/L of NaOL. Compared with original AMD, the final removal of toxic and hazardous ions of Fe, Al, Cd, Sn, Co, Ni, Zn, and Mn were 97.61 %, 98.85 %, 98.21 %, 97.78 %, 97.22 %, 99.34 %, 99.89 %, and 99.14 %, respectively. Additionally, the solid content of produced sludge was 27 %. Mechanistic inquiries revealed that A-100 and NaOL both chemically adsorbed on the particle surface and respectively enhanced the collision and attachment probabilities between precipitate particles and bubbles, thereby augmenting the separation efficiency. Furthermore, shortening the flotation column reduced the particle flotation path, thereby improving the flotation efficiency. The efficient PFD process exhibits significant advantages of rapid and effective AMD treatment, high sludge solid content, small footprint, and high relocatable convenience, demonstrating satisfactory cost effectiveness and significant potential as a replacement of the HDS process for AMD treatment.

Effect of titanium alkoxide on structure, morphology, and biocompatible properties of sol-gel synthesized TiO2 films

The purpose of this work was to study the influence of the nature of titanium alkoxide, used as a precursor for the synthesis of TiO2 films by the sol-gel method, on the crystal structure and morphology of coatings, as well as their biological compatibility. TiO2 coatings were synthesized on silicon substrates using the dip-coating method. Titanium alkoxides with different molecular weights were used as precursors: titanium tetraethoxide, titanium tetraisopropoxide, and titanium tetrabutoxide. The influence of the nature of the titanium precursor on the morphology and thickness of TiO2 films was determined using scanning electron microscopy. The structural properties of the coatings were studied by X-ray diffraction and Raman spectroscopy. Cell viability assay was performed on TiO2/Cu-Si(111) structures to evaluate the ability of TiO2 coatings synthesized from different precursors to prevent the release of toxic ions from the substrate. The biological compatibility of TiO2 films with various surface morphologies and structures was assessed based on the chorioallantoic membrane assay. It has been demonstrated that the type of titanium alkoxide utilized has a substantial influence on the morphology and crystal structure of TiO2 films produced through the sol-gel method. Furthermore, the structural properties of the coatings consequently impact their biological compatibility. Coatings synthesized from titanium tetrabutoxide exhibited the highest protective properties and biological compatibility.

Arabidopsis AGB1 participates in salinity response through bZIP17-mediated unfolded protein response

BackgroundPlant heterotrimeric G proteins respond to various environmental stresses, including high salinity. It is known that Gβ subunit AGB1 functions in maintaining local and systemic Na+/K+ homeostasis to accommodate ionic toxicity under salt stress. However, whether AGB1 contributes to regulating gene expression for seedling’s survival under high salinity remains unclear.ResultsWe showed that AGB1-Venus localized to nuclei when facing excessive salt, and the induction of a set of bZIP17-dependent salt stress-responsive genes was reduced in the agb1 mutant. We confirmed both genetic and physical interactions of AGB1 and bZIP17 in plant salinity response by comparing salt responses in the single and double mutants of agb1 and bzip17 and by BiFC assay, respectively. In addition, we show that AGB1 depletion decreases nuclei-localization of transgenic mRFP-bZIP17 under salt stress, as shown in s1p s2p double mutant in the Agrobacteria-mediated transient mRFP-bZIP17 expression in young seedlings.ConclusionsOur results indicate that AGB1 functions in S1P and/or S2P-mediated proteolytic processing of bZIP17 under salt stress to regulate the induction of salinity-responsive gene expression.

Ions release stages of Cu-Pb-Zn mine tailings waste: A column leaching simulation

Characterizing the leaching behavior and temporal variability of tailings is conducive to managing and preventing ionic toxicity to indigenous communities and environment. For this purpose, this work selected Cu-Pb-Zn tailings waste from Huili County, Sichuan province in China, as a research case, conducting a 60-day column leaching experiment to simulate the leaching behavior of the tailings. The results reveal that the weathering features of tailings, both salt-based ions and potential toxic elements (PTEs), could be subdivided into the rapid dissolution stage and carbonate dissolution stage. Additionally, acid rain can accelerate the weathering of calcite and dolomite, as well as the leaching of PTEs. The weathering of calcite precedes that of dolomite. A bulk release of PTEs occurs in the early stages, ranging approximately between 10.9 % and 33.6 % in the initial seven days, with As and Zn showing notable significance. Therefore, ecological effects of this abnormality necessitate thorough examination, given that the release of PTEs occurs over an extended and prolonged duration. Acid rain can promote ion desorption and weathering of major minerals, thereby facilitating the leaching of salt-based ions and PTEs. This study emphasizes the early rapid release stage of ions pollution from tailings, providing a preliminary understanding of the environmental impacts that may arise from tailings deposition and acidic rain leaching.

Microbial alchemists: unveiling the hidden potentials of halophilic organisms for soil restoration.

Salinity, resulting from various contaminants, is a major concern to global crop cultivation. Soil salinity results in increased osmotic stress, oxidative stress, specific ion toxicity, nutrient deficiency in plants, groundwater contamination, and negative impacts on biogeochemical cycles. Leaching, the prevailing remediation method, is expensive, energy-intensive, demands more fresh water, and also causes nutrient loss which leads to infertile cropland and eutrophication of water bodies. Moreover, in soils co-contaminated with persistent organic pollutants, heavy metals, and textile dyes, leaching techniques may not be effective. It promotes the adoption of microbial remediation as an effective and eco-friendly method. Common microbes such as Pseudomonas, Trichoderma, and Bacillus often struggle to survive in high-saline conditions due to osmotic stress, ion imbalance, and protein denaturation. Halophiles, capable of withstanding high-saline conditions, exhibit a remarkable ability to utilize a broad spectrum of organic pollutants as carbon sources and restore the polluted environment. Furthermore, halophiles can enhance plant growth under stress conditions and produce vital bio-enzymes. Halophilic microorganisms can contribute to increasing soil microbial diversity, pollutant degradation, stabilizing soil structure, participating in nutrient dynamics, bio-geochemical cycles, enhancing soil fertility, and crop growth. This review provides an in-depth analysis of pollutant degradation, salt-tolerating mechanisms, and plant-soil-microbe interaction and offers a holistic perspective on their potential for soil restoration.