Search Results (201)

Soil salinity adversely affects crop growth and development, leading to reduced soil fertility and agricultural productivity. The indigenous salt-tolerant plant growth-promoting rhizobacteria (PGPR), as a sustainable microbial resource, do not only promote growth and alleviate salt stress, but also improve the soil microecology of crops. The strain H5 isolated from saline-alkali soil in Bachu of Xinjiang was studied through whole-genome analysis, functional annotation, and plant growth-promoting, salt-tolerant trait gene analysis. Phylogenetic tree analysis and 16S rDNA sequencing confirmed its classification within the genus Halomonas. Functional annotation revealed that the H5 genome harbored multiple functional gene clusters associated with plant growth promotion and salt tolerance, which were critically involved in key biological processes such as bacterial survival, nutrient acquisition, environmental adaptation, and plant growth promotion. The pot experiment under moderate salt stress demonstrated that seed inoculation with Halomonas sp. H5 not only significantly improved the agronomic traits of tomato seedlings, but also increased plant antioxidant enzyme activities under salt stress. Additionally, soil analysis revealed H5 treatment significantly decreased the total salt (9.33%) and electrical conductivity (8.09%), while significantly improving organic matter content (11.19%) and total nitrogen content (10.81%), respectively (p < 0.05). Inoculation of strain H5 induced taxonomic and functional shifts in the rhizosphere microbial community, increasing the relative abundance of microorganisms associated with plant growth-promoting and carbon and nitrogen cycles, and reduced the relative abundance of the genera Alternaria (15.14%) and Fusarium (9.76%), which are closely related to tomato diseases (p < 0.05). Overall, this strain exhibits significant potential in alleviating abiotic stress, enhancing growth, improving disease resistance, and optimizing soil microecological conditions in tomato plants. These results provide a valuable microbial resource for saline soil remediation and utilization. Full article

The utilization of saline–alkali land for rice cultivation is critical for global food security. However, most existing studies on rice salt tolerance focus on the seedling stage, with limited insights into tolerance mechanisms during reproductive growth, particularly at the panicle initiation stage (PI). Leveraging precision salinity-control facilities, this study imposed four salt stress gradients (0, 3, 5, and 7‰) to dissect the differential response mechanisms of six rice varieties (YXYZ: Yuxiangyouzhan, JLY3261: Jingliangyou3261, SLY91: Shuangliangyou91, SLY138: Shuangliangyou138, HLYYHSM: Hualiangyouyuehesimiao, and SLY11:Shuangliangyou111) during PI. The results revealed that increasing salinity significantly reduced tiller number (13.14–68.04%), leaf area index (18.58–57.99%), canopy light interception rate (11.91–44.08%), and net photosynthetic rate (2.63–52.42%) (p < 0.001), accompanied by reactive oxygen species (ROS)-induced membrane lipid peroxidation. Integrative analysis of field phenotypic and physiological indices revealed distinct adaptation strategies: JLY3261 rapidly activated antioxidant enzymes under 3‰ salinity, alleviating lipid peroxidation (no significant difference in H₂O₂ or malondialdehyde content compared to 0‰ salinity) and maintaining tillering and aboveground biomass. SLY91 tolerated 7‰ salinity via CAT/POD-mediated lipid peroxide degradation, with H₂O₂ and malondialdehyde contents increasing initially but decreasing with escalating stress. These findings highlight genotype-specific antioxidant strategies underlying salt-tolerance mechanisms and the critical need for integrating phenomics–physiological assessments at reproductive stages into salt-tolerance breeding pipelines. Full article

Accurate gene expression quantification using reverse transcription quantitative PCR (RT-qPCR) requires stable reference genes (RGs) for reliable normalization. However, few studies have systematically identified RGs suitable for simultaneous high salt, alkaline, and high-temperature conditions. This study addresses this gap by evaluating the stability of eight candidate RGs in the anaerobic halophilic alkalithermophile Natranaerobius thermophilus JW/NM-WN-LF^T under combined salt, alkali, and thermal stresses. The stability of these candidate RGs was assessed using five statistical algorithms: Delta CT, geNorm, NormFinder, BestKeeper, and RefFinder. Results indicated that recA exhibited the highest expression stability across all tested conditions and proved adequate as a single RG for normalization in both RT-qPCR and droplet digital PCR (ddPCR) assays. Furthermore, recA alone or combined with other RGs (sigA, rsmH) effectively normalized the expression of seven stress-response genes (proX, opuAC, mnhE, nhaC, trkH, ducA, and pimT). This work represents the first systematic validation of RGs under polyextreme stress conditions, providing essential guidelines for future gene expression studies in extreme environments and aiding research on microbial adaptation mechanisms in halophilic, alkaliphilic, and thermophilic microorganisms. Full article

Superhydrophobic coatings possess distinct wettability characteristics and hold significant potential in metal corrosion protection and underwater drag reduction. However, their practical application is often hindered by poor durability arising from the fragility of their micro/nanostructured surface roughness. In this study, a durable superhydrophobic coating featuring a hierarchical, hydrangea-like micro/nanostructure was successfully fabricated on an aluminum alloy substrate via a simple one-step cold-spraying technique. The coating consisted of hydrangea-shaped SiO₂ nanoparticles modified with 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (PFDT) to produce multiscale roughness, while epoxy resin (EP) served as the binding matrix to enhance mechanical integrity. The hydrangea-like SiO₂ nanostructures were characterized by solid cores and wrinkled, petal-like outgrowths. This unique morphology not only increased the surface roughness but also provided more active sites for air entrapment, thereby enhancing the coating’s overall performance. The h-SiO₂@PFDT-EP composite coating exhibited excellent superhydrophobicity, with a WCA of 170.1° ± 0.8° and a SA of 2.7° ± 0.5°. Durability was evaluated through sandpaper abrasion, tape peeling, acid and alkali immersion, artificial weathering, and salt spray tests. The results demonstrated that the coating retained stable superhydrophobic performance under various environmental stresses. Compared with bare 6061 aluminum and EP coatings, its corrosion current density was reduced by four and three orders of magnitude, respectively. Furthermore, the coating achieved a maximum drag-reduction rate of 31.01% within a velocity range of 1.31–7.86 m/s. The coating also displayed excellent self-cleaning properties. Owing to its outstanding durability, corrosion resistance, and drag-reducing capability, this one-step fabricated superhydrophobic coating showed great promise for applications in marine engineering and defense. Full article

Soil salinization, affecting approximately 954 million hectares globally, severely impairs plant growth and agricultural productivity. Apocynum venetum L., a perennial herbaceous plant with ecological and economic value, demonstrates remarkable tolerance to saline and alkali soils. This study investigated the effects of saline (NaCl) and alkali (Na₂CO₃ and NaHCO₃) stress on the growth, anatomical adaptations, and metabolite accumulation of A. venetum (Apocynum venetum L.). Results showed that alkali stress (100 mM Na₂CO₃ and 50 mM NaHCO₃) inhibited growth more than saline stress (NaCl 240 mM), reducing plant height by 29.36%. Anatomical adaptations included a 40.32% increase in the root cortex-to-diameter ratio (100 mM Na₂CO₃ and 50 mM NaHCO₃), a 101.52% enlargement of xylem vessel diameter (NaCl 240 mM), and a 68.69% thickening of phloem fiber walls in the stem (NaCl 240 mM), enhancing water absorption, salt exclusion, and structural support. Additionally, leaf palisade tissue densification (44.68% increase at NaCl 160 mM), along with epidermal and wax layer adjustments, balanced photosynthesis and water efficiency. Metabolic responses varied with stress conditions. Root soluble sugar content increased 49.28% at NaCl 160 mM. Flavonoid accumulation in roots increased 53.58% at Na₂CO₃ 100 mM and NaHCO₃ 50 mM, enhancing antioxidant defense. However, chlorophyll content and photosynthetic efficiency declined with increasing stress intensity. This study emphasizes the coordinated adaptations of A. venetum, providing valuable insights for the development of salt-tolerant crops. Full article

In order to mitigate the reduction in soybean yield caused by soil salinization, a soybean gene, GmSNF4, which promotes plant tolerance to salt–alkali stress, was identified in this study. The STRING database was used to predict the interaction between GmSNF4 and GmPKS4. The GmPKS4 gene was experimentally shown to be involved in salt–alkali stress tolerance. Firstly, the yeast two-hybrid technique and bimolecular fluorescence complementation (BiFC) technique were used to confirm the interaction between GmSNF4 and GmPKS4: the AMPK-CBM-CBS1 conserved domain was thereby determined to be the region of the GmSNF4 protein involved in the interaction. Secondly, the GmSNF4 gene was induced by salt–alkali stress according to qRT-PCR analysis, and the GmSNF4 protein was localized in the nucleus and cytoplasm. Finally, analysis of GmSNF4’s role in resistance to salt–alkali stress in transgenic soybean plants showed that transgenic lines had better phenotypic, physiological, and stress-related gene expression than non-transgenic soybeans. Thus, GmSNF4 may play a significant role in plant salt–alkali stress tolerance. Full article

Limited research has been conducted on the potential and mechanisms of irrigating Suaeda salsa with wastewater and microalgae to improve saline–alkali land. This study used three irrigation treatments (freshwater, saline wastewater, and saline wastewater with microalgae) to irrigate S. salsa, and microalgae promoted the growth of S. salsa and increased soil nutrient content, increasing available nitrogen (4.85%), available phosphorus (44.51%), and organic carbon (24.05%) while alleviating salt stress through reduced soil salinity (13.52%) and electrical conductivity (21.62%). These changes promoted eutrophic bacteria while inhibiting oligotrophic bacteria. Bacterial community composition exhibited significant variations, primarily driven by soil pH, total nitrogen, and organic carbon content. Notably, rhizosphere bacteria showed enhanced functional capabilities, with increased abundance of salt stress resistance and nitrogen metabolism-related genes compared to original soil, particularly under saline irrigation conditions. Furthermore, microalgae addition enriched nitrogen metabolism-related gene abundance. These findings revealed the potential role of key bacteria in enhancing plant growth and the soil environment and highlighted the potential of applying S. salsa, wastewater, and microalgae for the synergistic improvement of saline–alkali land. Full article

MYB transcription factors constitute a diverse and functionally versatile family, playing central roles in regulating plant responses to a range of abiotic stressors. Based on previous research, we identified and characterized a maize MYB transcription factor gene, ZmMYBR24, which is involved in responses to salt, alkali, and low-temperature stress. This study aimed to investigate the function and mechanism of ZmMYBR24 in response to salt, alkali, and low-temperature stresses. We hypothesized that ZmMYBR24 regulates biosynthetic pathways to influence maize resistance to multiple abiotic stresses. The results indicate that ZmMYBR24 expression was markedly upregulated (p < 0.01) and the fold-change in gene expression ranged from 1.54 to 25.69 when plants were exposed to these combined stresses. Phenotypically, the zmmybr24 mutant line exhibited more pronounced inhibition of seedling and root growth under stress compared to the wild-type B73 line. Based on a correlation expression pattern analysis and mutant line evaluation, ZmMYBR24 was confirmed to be a positive regulatory transcription factor for multiple types of abiotic stress resistance. An RNA-seq analysis of both lines revealed differentially expressed genes (DEGs), with gene ontology (GO) and KEGG enrichment analyses indicating that ZmMYBR24 may mediate stress responses by modulating the expression of genes involved in flavonoid biosynthesis. Notable differences were observed in the expression of pathway-associated genes between the mutant and wild-type plants. A haplotype analysis across 80 inbred maize lines revealed 16 ZmMYBR24 coding region haplotypes—comprising 25 SNPs and 17 InDels—with HAP12 emerging as a superior haplotype. These results demonstrate that ZmMYBR24 enhances maize yields by regulating the flavonoid biosynthesis pathway in response to adverse climatic conditions including salt, alkaline conditions, and low temperatures. Collectively, these findings offer novel insights into the molecular mechanisms underlying maize adaptation to combined abiotic stresses and lay the groundwork for breeding programs targeting multi-stress resistance. Full article

Vibrio species are among the primary pathogenic bacteria affecting abalone aquaculture, posing significant threats to farming practices. Current clinical control predominantly relies on antibiotics, which can result in antibiotic residues in both abalone and the surrounding marine environments. Lactobacillus plantarum (LP) has been shown to release bioactive antagonistic substances and exhibits potent inhibitory effects against marine pathogenic bacteria. This study aimed to screen and characterize the probiotic properties of LP strains isolated from rice wine lees to develop a novel biocontrol strategy against Vibriosis in abalone. The methods employed included selective media cultivation, streak plate isolation, and single-colony purification for strain screening, followed by Gram staining, 16S rDNA sequencing, and phylogenetic tree construction using MEGA11 for identification. The resilience, antimicrobial activity, and in vivo antagonistic efficacy of the strains were evaluated through stress tolerance assays, agar diffusion tests, and animal experiments. The results demonstrated the successful isolation and purification of four LP strains (NDMJ-1 to NDMJ-4). Phylogenetic analysis revealed closer genetic relationships between NDMJ-3 and NDMJ-4, while NDMJ-1 and NDMJ-2 were found to be more distantly related. All strains exhibited γ-hemolytic activity, bile salt tolerance (0.3–3.0%), and resistance to both acid (pH 2.5) and alkali (pH 8.5), although they were temperature sensitive (inactivated above 45 °C). The strains showed susceptibility to most of the 20 tested antibiotics, with marked variations in hydrophobicity (1.91–93.15%) and auto-aggregation (13.29–60.63%). In vitro antibacterial assays revealed that cell-free supernatants of the strains significantly inhibited Vibrio parahaemolyticus, V. alginolyticus, and V. natriegens, with NDMJ-4 displaying the strongest inhibitory activity. In vivo experiments confirmed that NDMJ-4 significantly reduced mortality in abalone infected with V. parahaemolyticus. In conclusion, the LP strains isolated from rice wine lees (NDMJ-1 to NDMJ-4) possess robust stress resistance, adhesion capabilities, and broad antibiotic susceptibility. Their metabolites exhibit significant inhibition against abalone-pathogenic Vibrios, particularly NDMJ-4, which demonstrates exceptional potential as a candidate strain for developing eco-friendly biocontrol agents against Vibriosis in abalone aquaculture. Full article

Soil salinization limits global agricultural sustainability, and extensive areas of saline–alkaline soils on the Qinghai–Tibet Plateau remain underutilized. Against this backdrop, this study evaluated the effects and ecological regulatory mechanisms of potassium fulvate (PF) application on oat (Avena sativa L.) growth, soil properties, and rhizosphere microbial communities in the saline–alkali soils of the Qaidam Basin. The results showed that PF significantly enhanced both aboveground and belowground biomass and improved root morphological traits, with the higher application rate (150 kg·hm⁻²) showing superior performance. PF also effectively improved soil nutrient conditions (organic matter, ammonium nitrogen, and potassium), reduced the integrated salinity–alkalinity index, significantly optimized the composition of rhizosphere soil cations (increased K⁺ and Ca²⁺; decreased Na⁺ and Mg²⁺), and induced a marked reshaping of the composition and structure of rhizosphere microbial communities. Notably, microbial β-diversity exhibited a significant regulatory effect on the comprehensive growth of oats. Structural equation modeling (SEM) revealed that PF primarily promoted oat growth indirectly by improving soil physicochemical properties (direct effect = 0.94), while the microbial community structure served as a synergistic ecological mediator. This study clarifies the regulatory mechanisms of PF in oat cultivation under alpine saline–alkali conditions, providing both theoretical and practical support for improving soil quality, enhancing forage productivity, and promoting sustainable agriculture in cold regions. Full article

Salinity stress is a major environmental challenge that adversely impacts the physiological and biochemical processes of pasture, consequently resulting in reduced yields and compromised quality. Biochar amendment has recently emerged as a promising strategy to alleviate the deleterious effects of salinity stress. However, the interactive influences of salinity stress and wheat straw biochar on the physiological, biochemical, and growth characteristics of alfalfa (Medicago sativa L.) remain underexplored. A factorial experiment was conducted using a randomized complete design with five salinity levels (0, 25, 50, 75, and 100 mM NaCl) and three application rates of biochar (0, 25, and 50 g kg⁻¹) to evaluate wheat straw biochar’s potential in alleviating salinity stress in alfalfa. Results showed that salinity stress increased oxidative stress (hydrogen peroxide and malondialdehyde) and reduced chlorophyll fluorescence (maximum quantum efficiency of photosystem II by 1–27%), leading to decreasing photosynthetic parameters, thereby constraining biomass accumulation by 9–77%. Wheat straw biochar amendment under the highest salinity stress, particularly at 25 g kg⁻¹, mitigated oxidative stress by reducing H₂O₂ and MDA levels by 35% and 33%, respectively, while decreasing the antioxidant enzymes activities of CAT, POD, and SOD by 47%, 42%, and 39%, respectively, compared to the control (non-biochar addition). Concurrently, biochar restored the osmoregulatory substance concentrations of proline and soluble sugar by 59% and 33%, respectively, compared to the control. Furthermore, wheat straw biochar amendment increased the net CO₂ assimilation rate by 98%, thereby increasing biomass by 63%. Our study demonstrates that wheat straw biochar can contribute to protecting alfalfa against salinity stress by modulating physiological and biochemical responses. These findings demonstrate that the 25 g kg⁻¹ wheat straw biochar application had the best performance, suggesting this amendment could be a viable strategy for improving alfalfa productivity in salt-affected soils. Future research should explore long-term field applications and the underlying mechanisms of biochar–plant–soil–plant interactions under diverse saline-alkali environments. Full article

The strain of Oceanobacillus picturae DY09, as a typical halophilic microorganism, possesses distinctive salt adaptation mechanisms that hold significant application value in the fields of agriculture, industry, and biomedicine. To deeply analyze the salt-tolerance molecular mechanism of this strain, this research disclosed its salt-tolerance strategies under diverse salt concentrations through transcriptomics. In a low-salt environment, the DY09 strain adopted a “metabolic simplification” strategy, significantly reducing the metabolic load by promoting lysine degradation and inhibiting the biosynthesis of branched-chain amino acids and glycine betaine (GB) but upregulating the expression of the GB transporter gene betH and preferentially utilizing exogenous GB to maintain basic osmotic balance. When exposed to high-salt stress, this strain activated multiple regulatory mechanisms: it upregulated the expression of Na⁺/K⁺ antiporter proteins to maintain ionic homeostasis; the synthesis genes of amino acids such as arginine and proline were significantly upregulated, and the GB synthesis genes betA/B and the transporter gene betH were upregulated concurrently, which realized the synergistic operation of endogenous synthesis and exogenous uptake of osmoprotective substances. The expression level of the antioxidant enzyme systems is upregulated to scavenge reactive oxygen species. Simultaneously, the molecular chaperones groES/groEL and GB cooperate to maintain the functional stability of the protein. In this study, a trinity salt-tolerance-integrated strategy of “dynamic perception–hierarchical response–system synergy” of halophilic bacteria was initially proposed, which provided a research idea for exploring the salt–alkali-tolerant mechanism of halophilic bacteria and a theoretical basis for the further development and application of this strain. Full article

Background/Objectives: Understanding metabolome adjustment under saline–alkaline conditions is crucial for enhancing crop tolerance capacity and ensuring food security. Although soil salinization impairs wheat seedlings’ growth, metabolome plasticity under saline–alkaline stress remains poorly understood. Here, we delved into dynamic physiological and metabolome shifts in wheat seedlings grown on SAS (saline–alkaline soil) on the 7th and 15th days post-germination (DPG). Methods: A self-developed and cultivated high-generation salt–alkali wheat variety (011) was grown on SAS and control soil, followed by comparative physiological, biochemical, and metabolomics analyses of seedlings. Results: The seedlings’ saline–alkaline stress responses were developmentally regulated with reduced growth, increasing accumulation of proline and soluble sugars, and differential antioxidant response. LC-MS-based global metabolomics analysis revealed significant metabolite profile differences, with 367 and 485 differential metabolites identified on the 7th and 15th DPG, respectively, between control and treatment. Upregulation of saccharides, flavonoids, organic acids (citrate cycle-related), phenolic acids, amino acids and derivatives, phytohormones, and sphingolipid metabolism was essential for seedlings’ growth on SAS. The key induced metabolites in seedlings grown on SAS include saccharic acid, trehalose, sucrose, glucose, L-citramalic acid, phellodendroside, scutellarin, anthranilate-1-O-sophoroside, lavandulifolioside, N-methyl-L-glutamate, etc. Up-regulated phytohormones include abscisic acid (3.8-fold, 7th DPG and 3.18-fold, 15th DPG), jasmonic acid (1.93-fold, 15th DPG), and jasmonoyl isoleucine (2.03-fold, 15th DPG). Conclusions: Our findings highlight the importance of ABA and jasmonic acid in regulating salt–alkali tolerance in wheat seedlings. Moreover, this study depicts key pathways involved in salt–alkali tolerance in wheat seedlings and unveils key DMs, offering resources for boosting wheat production on SAS. Full article

Plants dynamically regulate ions in the tree to defend against abiotic stresses such as drought and saline-alkali, However, it is not clear how ‘Junzao’ jujube regulates ions to maintain a normal life cycle under saline-alkali stress. Therefore, in this study, the roots of 10-year old steer jujube trees were watered using a saline and alkaline gradient solution simulating the main salt (NaCl) and alkali (NaHCO₃) of Aral with NaCl:NaHCO₃ = 3:1 gradient of 0, 60, 180, and 300 mM, and three jujube trees with uniform growth were taken as samples in each treatment plot, and the ion contents of potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn) and carbon (C) in each organ of the fruit at the dot red period (S1) and full-red period (S2) were determined, in order to elucidate the relationship between physiological adaptation mechanisms of saline-alkali tolerance and the characteristics of mineral nutrient uptake and utilisation in jujube fruit. The results showed that under saline-alkali stress, Na was stored in large quantities in the roots, Ca and Mg in the perennial branches at S1, Na and Fe in the leaves at S2, and K, Mg and Mn in the perennial branches. There was no significant difference in the distribution of C content in various organs of ‘Junzao’. Compared with CK (0 mM), under salinity stress, the K content in the leaves was significantly reduced at S1 and S2, and the K/Na ratios remained > 1.0. At S2, under medium and high concentrations of saline-alkali stress (180–300 mM), the K/Na is less than 1, and the ionic homeostasis was disrupted, and the leaves die and fall off, and the Na is excreted from the body. The selective transport coefficients SK/Na, SCa/Na and SMg/Na from root to leaf showed a downward trend at S1, but still maintained positive transport capacity. At S2, this stage is close to leaf fall, the nutrient transport coefficient is less than 1, and a large amount of nutrients are returned to the perennial branches and roots occurred. These results indicated that the mechanism of nutrient regulation and salt tolerance in jujube trees was different at different growth stages. Full article

BEL1-like homeodomain protein 3 (BLH3) plays a crucial role in plant development. However, its involvement in the salt stress response has not been studied. In this study, we investigated the molecular mechanism underlying the response of LpBLH3 to salt stress in Lilium pumilum (L. pumilum) using various techniques, including quantitative PCR (RT-qPCR), determination of physiological indices of plant after Saline-Alkali stress, yeast two-hybrid screening, luciferase complementation imaging (LCI), and chromosome walking to obtain the promoter sequence, analyzed by PlantCARE, electrophoretic mobility shift assay (EMSA), and then dual-luciferase reporter assay(LUC). RT-qPCR analysis revealed that LpBLH3 is most highly expressed in the leaves of L. pumilum. The expression of LpBLH3 peaks at 24 or 36 h in the leaves under different saline stress. Under various treatments, compared to the wild type (WT), the LpBLH3 overexpression lines exhibited less chlorosis and leaf curling and stronger photosynthesis. The overexpression of LpBLH3 can enhance lignin accumulation in root and stem by positively modulating the expression of crucial genes within the lignin biosynthesis pathway. Y2H and LCI analyses demonstrated that LpBLH3 interacts with LpKNAT3. Additionally, EMSA and LUC analyses confirmed that LpBLH3 can bind to the promoter of LpABI5 and upregulate the expression of ABI5 downstream genes (LpCAT1/LpATEM/LpRD29B). In summary, LpBLH3 enhances the plant’s salt tolerance through the ABA pathway and lignin synthesis. This study can enrich the functional network of the BLH transcription factor family, obtain Lilium pumilum lines with good saline-alkali resistance, expand the planting area of Lilium pumilum, and improve its medicinal and ornamental values. Additionally, the functional analysis of the BLH transcription factor family provides new insights into how crops adapt to the extreme growth environment of saline-alkali soils. Full article