Search Results (2,117)

Osmotic stress severely limits the growth and development of tomato (Solanum lycopersicum L.) by reducing cellular water potential, disrupting redox homeostasis, and impairing physiological functions. Micro–nano bubble (MNB) treatment can increase dissolved oxygen in the root-zone solution and improve the root-zone environment, which may benefit root metabolic activity and stress adaptation. However, the underlying molecular mechanisms are still not elucidated. To explore the underlying molecular mechanisms of how MNB-mediated root oxygenation alleviates osmotic stress in tomato, we have integrated the physiological and biochemical alterations, variable-pressure scanning electron microscopy (VP-SEM), and transcriptomic analysis (RNA-seq) under osmotic stress. The results revealed that MNBs significantly reduced PEG-induced wilting and decreased reactive oxygen species (ROS) accumulation and relative electrical conductivity (REC). Indeed, MNBs also markedly upregulated the expression of root aquaporins PIP2.7 and PIP2.4, suppressed the expression of NCED1 in leaves, and increased levels of endogenous growth-promoting hormones, including IAA and GA₃, under osmotic stress. VP-SEM observations showed that MNB-treated plants exhibited a relatively more open stomatal appearance compared with PEG-treated plants. Together, these findings suggest that MNBs mitigate PEG-induced osmotic stress in tomato, potentially by improving the root-zone aeration environment and coordinating water transport-related gene expression, antioxidant defense, and hormonal balance. These results provide a promising physical approach and theoretical basis for improving tomato stress tolerance under osmotic stress. Full article

Silage maize (Zea mays L.) serves as a key source of high-quality roughage for ruminants, yet its production and the development of the silage maize industry in Xinjiang are severely constrained by saline–alkali stress. In this study, root growth phenotypes, root energy metabolism, cell membrane stability, osmotic regulatory substances, and reactive oxygen species (ROS) metabolism were examined to elucidate the mechanisms by which iron chlorin e6 (ICe6) enhances saline–alkali tolerance in maize roots. The results showed that saline–alkali stress significantly suppressed root growth in maize seedlings, leading to increased malondialdehyde (MDA) content and relative conductivity. This suggests that membrane lipid peroxidation has intensified, resulting in increased cell membrane permeability. Meanwhile, ICe6 enhanced antioxidant enzyme (SOD, POD, CAT, and APX) activities, scavenged H₂O₂ accumulation, reduced MDA content, and stabilized cell membrane integrity, as indicated by reduced ion leakage. Moreover, ICe6 optimized root respiratory pathways, improved root vigor, and ATP synthesis to provide adequate energy for growth, while decreasing free proline accumulation to maintain cellular osmotic balance. These findings demonstrate that ICe6 mitigates saline–alkali stress in silage maize roots through coordinated regulation of energy metabolism, antioxidant defense, and osmotic adjustment. Full article

Plant AT-rich sequence and zinc-binding proteins (PLATZs) act as critical modulators of plant growth, development, and responses to environmental stressors. Nevertheless, the PLATZ gene family (StPLATZs) has not yet been systematically characterized in potato, and this study seeks to identify members and prioritize genes associated with abiotic stress. A total of 13 StPLATZ genes were identified in the potato genome and classified into three distinct subfamilies based on phylogenetic analysis. Expression profiling and qRT-PCR analysis indicated that several StPLATZ genes responded to abiotic stress treatments. Yeast-based functional analysis suggested that Soltu06G018660 improved tolerance to PEG-induced osmotic stress, indicating its potential involvement in osmotic stress responses. These results provide candidate genes and hypotheses for future functional validation in potato. Further in-depth research on StPLATZs may contribute to potato stress-tolerance breeding. Full article

Driven by increasingly severe drought stress associated with global warming, this study investigated a synthetic microbial community, SynCom-SASW01, with strong stress tolerance and plant growth-promoting potential, and systematically elucidated its mechanisms for enhancing drought resistance in wheat (Triticum aestivum L.). Dual-site field trials demonstrated that SynCom-SASW01 significantly alleviated drought-induced growth suppression, increasing grain yields by 10.42% and 8.52% at the Hohhot and Hulunbuir sites, respectively. This improvement was primarily associated with increased effective tiller number and enhanced root vigor. Physiologically, inoculation promoted root proline and glutathione accumulation and enhanced antioxidant enzyme activities, including superoxide dismutase, thereby reducing malondialdehyde levels. Environmental analyses showed that the consortium established rhizosphere “micro-reservoirs” through exopolysaccharide secretion, improving soil relative water content and the availability of alkali-hydrolyzable nitrogen and phosphorus. High-throughput sequencing revealed that SynCom-SASW01 reshaped the endosphere microbiome through early colonization priority effects, selectively enriching beneficial taxa such as Pseudomonas. Functional prediction indicated upregulated branched-chain amino acid biosynthesis, promoting osmotic adjustment and redox homeostasis. These findings provide a microbiome-based strategy for stabilizing wheat productivity in arid regions. Full article

Drought impairs osmotic adjustment and photosynthetic performance in legumes; however, the role of micronutrients in modulating these responses across genotypes remains unclear. This study investigated the effects of selenium on the osmolytes and photosynthetic efficiency in two vegetable-soybean (Glycine max L. Merrill) cultivars differing in drought responses: UVE14 (drought-tolerant) and UVE17 (drought-susceptible). Plants were grown under well-watered (100% soil water-holding capacity, WHC) and water-limited (30% soil WHC) conditions, with or without soil-applied selenium. Free amino acids, soluble sugars, chlorophyll pigments, vegetation indices, and chlorophyll fluorescence parameters were assessed at the flowering and pod-filling stages. Under drought conditions, selenium enhanced tolerance primarily by modulating free amino acid metabolism at flowering, increasing aspartate, asparagine, glutamine, and glutamate levels, alongside improvements in chlorophyll content, canopy greenness, and PSII photochemical efficiency. These responses indicate a coordinated adjustment between nitrogen metabolism and photosynthetic function. Both cultivars benefited from selenium application, although the responses were more pronounced in the susceptible cultivar (UVE17). Selenium-induced changes in soluble sugar content were greater under well-watered conditions in both cultivars. The limited accumulation of stress-associated osmolytes, such as proline, following selenium soil drench suggests reduced cellular disruption and mitigation of drought-induced stress. These findings highlight selenium as a context-dependent modulator of drought resilience and emphasize cultivar- and developmental stage-specific effects. Full article

Drought stress is one of the most prevalent abiotic stressors and severely impairs plant growth and productivity. Therefore, identifying functional genes associated with drought tolerance is essential for the molecular breeding of drought-resistant crops. The RD22 (Responsive to Desiccation 22) gene family encodes conserved BURP domain-containing proteins that participate in plant responses to drought stress. In this study, two RD22 homologs, DsRD22a and DsRD22b, were isolated and characterized from the drought-tolerant ornamental species Dianthus spiculifolius. Sequence analysis showed that both proteins contain a conserved BURP domain and are typical members of the RD22 family. Tissue-specific expression analysis revealed that both genes were predominantly expressed in leaves and stems. Abiotic stress assays demonstrated that the expression levels of DsRD22a and DsRD22b were significantly induced by abscisic acid (ABA), osmotic stress, and salt stress, whereas their transcriptional responses to relatively low-temperature and oxidative stress were relatively weak. Subcellular localization analysis indicated that DsRD22a and DsRD22b proteins are localized in the cytoplasm. Heterologous overexpression assays showed that transgenic Arabidopsis thaliana lines overexpressing DsRD22a or DsRD22b exhibited significantly enhanced tolerance to salt and osmotic stresses compared with wild-type (WT) plants. Soil drought assays further confirmed that the transgenic lines had higher soluble protein contents and improved drought tolerance than WT plants. These findings suggest that DsRD22a and DsRD22b positively regulate plant responses to drought stress, potentially by promoting soluble protein accumulation. Collectively, DsRD22a and DsRD22b represent valuable candidate genes for the genetic improvement of drought tolerance in plants. Full article

In the context of global climate change, intensified salinity fluctuations driven by altered precipitation, extreme rainfall events, and typhoons have emerged as a major threat to coastal mollusk aquaculture. In this study, integrated physiological and transcriptomic analyses were performed to investigate the responses of Pacific abalone (DD, Haliotis discus hannai) and its hybrid (DF, H. discus hannai ♀ × H. fulgens ♂) to hypo- and hypersalinity stress. Two salinity breakpoints (BPS1 for hyposalinity, BPS2 for hypersalinity) were identified using heart rate monitoring to indicate the osmotic tolerance thresholds of the abalone. The BPS1 and BPS2 values did not differ significantly between the DD and DF groups. However, a subsequent 30-day culture trial confirmed that exposure to the salinity level corresponding to BPS1 significantly reduced growth and survival of both DD and DF groups. To explore the molecular mechanisms underlying these two salinity breakpoints in abalone, the transcriptomes of hemocytes and gill tissues were profiled under both stress conditions. Both hypo- and hypersalinity stress induced pronounced transcriptomic responses in abalone, accompanied by upregulated differentially expressed genes (DEGs) significantly enriched in pathways like TNF and NF-κB signaling, including genes like piap, diap2, birc7-a, birc2, and birc3. However, abalone exhibited more intense responses to hypersalinity stress, as reflected by a greater number of annotated differentially expressed genes (DEGs) and more complex transcriptional regulation. Overall, this study integrates physiological assessment based on heart rate monitoring, aquaculture trials, and transcriptomic analysis to advance our mechanistic understanding of osmotic stress adaptation in abalone, while laying a scientific foundation for the sustainable development of abalone aquaculture under global climate change. Full article

Earthworms possess a highly developed innate immune system based on the coordinated activity of coelomocytes and humoral factors present in the coelomic fluid. These immune components play a central role in host defence against pathogens, maintenance of physiological homeostasis, and adaptation to environmental stressors. Coelomocytes exhibit remarkable functional and morphological diversity, including participation in phagocytosis, encapsulation, extracellular trap formation, cytotoxic responses, wound healing, and regulation of oxidative and osmotic stress. In addition, coelomic fluid contains numerous biologically active molecules, such as lysenin, coelomic cytolytic factor 1, perforin, serine proteases, lysozyme, antimicrobial peptides, and pattern recognition receptors, which contribute to cellular and humoral immune responses. Recent studies have demonstrated that earthworm coelomocytes are highly sensitive to environmental pollutants, including heavy metals, pesticides, nanomaterials, and microplastics, highlighting their importance in ecotoxicological research and soil biomonitoring. Furthermore, antifungal, antimicrobial, anti-inflammatory, antipyretic, and cytotoxic activities associated with coelomocytes and coelomic fluid suggest promising applications in agriculture, biotechnology, and pharmaceutical research. This review summarises current knowledge regarding the classification, characteristics, immune functions, toxicological responses, and applied significance of earthworm coelomocytes and coelomic fluid, with particular emphasis on their role in environmental monitoring and potential biomedical applications. Full article

Glycine betaine transport systems are widely exploited by bacteria to survive osmotic stress and represent potential entry routes for antimicrobial delivery. Here, we investigate the bactericidal glycine betaine analog Tox-GB and its uptake, intracellular fate, and antimicrobial activity in Escherichia coli K-12 under osmotic stress. We show that the xenobiotic enters cells via a hierarchical uptake route involving the osmotically regulated compatible solute transporters ProU and ProP, ABC- and MFS-type transporters, respectively. ProU functions as the primary high-affinity transporter at low concentrations, whereas ProP provides a secondary uptake route at somewhat higher substrate levels. Loss of either transporter confers partial resistance, while simultaneous inactivation of both systems causes full resistance, underscoring their functional redundancy and the robustness of Tox-GB import. Intracellularly, Tox-GB undergoes oxygen-dependent degradation, yielding 4-nitrobenzaldehyde and dimethylglycine. While 4-nitrobenzaldehyde contributes to toxicity under aerobic conditions, Tox-GB remains bactericidal under anaerobic conditions, indicating additional oxygen-independent mechanisms involving either the parent compound or unidentified metabolites. These findings suggest a complex intracellular fate and multifactorial mode of action. Despite initial promise as a Trojan horse antimicrobial strategy, the use of Tox-GB for practical applications faces key limitations. Resistance readily emerges via transporter inactivation, and intrinsic resistance occurs in species lacking appropriate compatible solute uptake systems. Structural constraints in glycine betaine transporters further restrict design flexibility. Osmotic regulation limits activity to specific niches, and potential host toxicity stemming from reactive metabolites raises safety concerns. Collectively, these findings highlight the mechanistic complexity and translational challenges faced by glycine betaine–derived xenobiotics as antimicrobial agents. Full article

Free amino acids (FAAs) are important low-molecular-weight metabolites involved in osmotic regulation, acid–base balance, and nitrogen metabolism in fish exposed to saline–alkaline environments. To characterize tissue-specific FAA responses in mandarin fish (Siniperca chuatsi), 10 cm juveniles were exposed for 96 h to freshwater control (FW), salinity stress (S, salinity 8), alkalinity stress (A, alkalinity 20 mmol/L), or combined saline–alkaline stress (SA, salinity 8 + alkalinity 20 mmol/L). The contents of 19 FAAs were compared among plasma, muscle, liver, brain, and kidney. FAA profiles showed clear tissue specificity. Total FAA (17) decreased in plasma under all stress treatments, increased in muscle under S and SA but decreased under A, increased in liver and kidney, and decreased under single stress but increased under combined stress in brain. Distinct tissue distribution patterns were observed for functional FAA groups. Under salinity stress, osmoregulation-related FAAs, particularly Ala and Pro, showed higher contents mainly in muscle, liver, and kidney. Under alkalinity stress, kidney showed concurrent increases in multiple FAAs, including Ala, Pro, Glu, Gln, Val, Ile, and Leu, whereas brain was characterized by a high Gln content. Under combined saline–alkaline stress, liver was the main tissue in which multiple functional FAA groups increased simultaneously, kidney maintained elevated levels of several FAAs, and brain showed treatment-specific high levels of Gln and Tau. Redundancy analysis (RDA) indicated weak constrained explanatory power of salinity and alkalinity for the overall FAA profile, whereas tissue-specific differentiation was evident. Glu, Gln, and Pro showed directional consistency with the salinity vector, whereas Val and Leu tended to align with the alkalinity-related ordination direction. Overall, acute saline–alkaline exposure induced a functional and tissue-specific distribution pattern of FAAs rather than a uniform whole-body shift in mandarin fish. Full article

Identifying cold-resistance genes is essential for improving the ability of apples (Malus × domestica) to tolerate low temperatures, as cold stress significantly limits their growth and productivity. The MdWRKY31 gene was cloned from apple, and its sequence characteristics, expression pattern, and biological function were systematically investigated. Bioinformatic analysis indicated that MdWRKY31 belongs to the group II WRKY transcription factors and is localized in the nucleus. Expression analysis revealed that MdWRKY31 transcript levels were markedly upregulated under low-temperature stress. To further explore its function, MdWRKY31 was heterologously overexpressed in tomato (Solanum lycopersicum). Following low-temperature treatment, transgenic tomato plants exhibited significantly reduced accumulation of reactive oxygen species, markedly enhanced activities of antioxidant enzymes (SOD, POD, and CAT), increased contents of proline and soluble protein, and a notable decrease in malondialdehyde levels. Additionally, transcript levels of SlCBF1, SlCBF2, SlCBF3, SlICE1, along with the ABA signaling-related genes SlNCED1 and SlABI5, were markedly elevated. Further molecular docking showed that the MdWRKY31 protein has strong binding affinity to the W-box elements in the promoters of SlCBF1 suggesting that it may regulate the expression of these genes through direct protein–DNA interactions. These findings indicate that MdWRKY31 improves plant cold tolerance by CBF-dependent pathways to modulate antioxidant defenses and osmotic balance. These findings identify candidate genetic resources for breeding cold-resistant apple cultivation. Full article

Identifying superior salt-tolerant germplasm and resistance genes is crucial, as wheat (Triticum aestivum L.) seedlings are highly vulnerable to salt stress. Here, using an optimized 150 mM NaCl treatment, we screened 137 Chinese wheat accessions via an organ-specific method. Phenotyping analysis revealed extensive organ-specific divergence, with 48.91% of accessions displaying inconsistent performance between shoot and root length. We then performed comparative transcriptomics on three representative phenotypes at the seedling stage: Gaoyou 2018, representing the salt dual-sensitive group; Huapei 5, representing the salt dual-tolerant group; and Jimai 60, representing the divergent group with higher tolerance in shoots rather than in roots. Analysis of overlapping differentially expressed genes (DEGs) across all three accessions revealed a basal stress response—characterized by induced osmotic defense and suppressed primary growth—exemplifying a classical growth–defense trade-off. Genotype-specific DEG profiling demonstrated that the divergent Jimai 60 maintains its shoot advantage by reinforcing physical barriers and inhibiting apoptosis. Conversely, transcriptomic profiling implies that the systemically tolerant Huapei 5 maintains coordinated shoot and root tolerance at the seedling stage by strongly activating below-ground Na⁺ homeostasis (efflux and compartmentalization) while simultaneously down-regulating non-essential immune responses to optimize defense energy reallocation. Collectively, our findings provide novel insights into the organ-differentiated salt tolerance of wheat, offering well-characterized elite germplasm and compelling genetic targets for future molecular breeding. Full article

Polyamine treatments are beneficial against various stress factors due to direct protective effects and the regulation of metabolite remodelling and gene expression. However, their protective, specific effects as priming under stress conditions remain not fully understood. We hypothesised that the positive effect of priming decreases even shortly after priming. To investigate the duration of action of putrescine treatment against osmotic stress, and to reveal species- and time-dependent differences, the effects of putrescine seed-soaking were monitored in wheat and maize during osmotic stress. The putrescine pre-treatment was effective in both species against osmotic stress during three trials ran in parallel, even when the stress was applied 7 days after seed-soaking. Leaves and roots responded differently, and putrescine induced certain unique changes under control and osmotic stress conditions. The effects of the treatments at the metabolite level changed between the sub-experiments and differed between the two species. Putrescine alone had an increasing effect on jasmonic acid-isoleucine level in the roots of both wheat and maize, and it induced the expression of WRKY97 in both the leaves and roots of maize plants throughout the experiment. These results highlight that different hormonal and transcriptional changes induced by putrescine were associated with the observed positive effects. Full article

Alternative splicing (AS) is a major post-transcriptional regulatory mechanism that greatly expands transcriptomic and proteomic diversity in plants. Recent studies have demonstrated that AS dynamically regulates gene expression during plant development and under diverse environmental conditions through isoform-specific modulation of transcript stability, translation efficiency, protein localization, and signaling pathways. In this review, we summarize recent advances in understanding the roles of AS in plant development and abiotic stress responses. Mechanistically, splice site selection is regulated through coordinated interactions among cis-regulatory elements, RNA-binding proteins, RNA secondary structures, transcriptional kinetics, chromatin organization, and spliceosomal dynamics. AS plays critical roles in various developmental processes, including seed germination, vegetative growth, flowering transition, and senescence, while also contributing to plant adaptation to abiotic stresses such as osmotic, temperature, and oxidative stresses. Particular emphasis is placed on the diverse regulatory outcomes of AS, including isoform-specific protein functions, AS-coupled nonsense-mediated decay, transcript stability control, and context-dependent isoform switching. We further discuss the varying levels of experimental evidence supporting reported AS events, ranging from transcriptome-wide observations to genetically and biochemically validated isoform functions. Moreover, recent advances in long-read sequencing, single-cell transcriptomics, proteogenomics, and genome-engineering technologies are accelerating the functional characterization of splice isoforms and uncovering the complexity of AS-mediated regulatory networks. Collectively, these advances highlight AS as a central mechanism coordinating plant developmental plasticity and environmental adaptation. Full article

This study used Poacynum hendersonii (Hook. f.) Woods. seedlings as experimental material. A soil drought group (gradual soil drying) and a PEG-simulated drought group (15% PEG-6000 treatment) were established. By combining physiological measurements, metabolomics, and transcriptomics, we investigated the physiological and molecular mechanisms of P. hendersonii in response to drought stress. The results showed that under drought stress, P. hendersonii alleviated oxidative damage by activating the antioxidant enzyme system (catalase, CAT; superoxide dismutase, SOD; peroxidase, POD), and enzyme activities recovered significantly after rehydration. In the osmotic stress group (PEG), hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents increased significantly in the later stages, whereas membrane damage was milder in the soil drought group. Metabolomics analysis revealed significant enrichment of starch and sucrose metabolism pathways during early drought, shifting to unsaturated fatty acid biosynthesis and carbon metabolism in later stages. PEG-simulated drought specifically induced the accumulation of arachidonic acid, which may be associated with ferroptosis-like processes, although direct evidence is lacking. Transcriptomics analysis identified 23,623 differentially expressed genes (DEGs), with transcription factor families such as bHLH, MYB, and NAC playing key roles in drought response. Weighted Gene Co-expression Network Analysis (WGCNA) further revealed gene modules significantly correlated with physiological traits, indicating that enhanced respiratory metabolism (glycolysis, tricarboxylic acid (TCA) cycle) is an important strategy for P. hendersonii to adapt to drought. The study also found that while PEG-simulated drought could simulate the physiological effects of soil drought, significant differences existed in molecular pathways, particularly during later stress stages. This research provides a theoretical basis for elucidating the drought resistance mechanisms of P. hendersonii and offers potential targets for crop drought resistance breeding. Full article