Search Results (7,744)

Abiotic stresses affect the growth of tea plants (Camellia sinensis) and reduce their yield and quality. The tea plant is a perennial crop. Its adaptability to abiotic stresses and the formation of quality depend not only on internal physiological regulation, but also on long-term interactions with the surrounding soil environment. However, how abiotic stresses reshape the tea rhizosphere community structure, and the knowledge of how these changes shape tea quality remains limited. This review summarizes current knowledge on the tea rhizosphere microbiome under abiotic stress. First, we examine how stress reshapes microbial communities, including their composition, metabolic functions, interaction networks, and the recruitment driven by root exudates. Second, we explore the mechanism of rhizosphere microorganisms affecting tea plants, including participation in nutrient cycling, interaction mediated by exudates, and the regulation of secondary metabolic pathways related to the quality of tea. Finally, we discuss several nutrient-based and microbiome-based management strategies, such as the use of combined fertilizer, intercropping, PGPR, AMF, and SynComs. This review connects stress physiology, rhizosphere ecology, and tea quality regulation within a microbiome-centered framework, providing a basis for strategies that enhance stress tolerance and tea quality stability in the tea plant. Full article

Biofilms are structured communities of microorganisms embedded in a self-produced extracellular polymeric substance (EPS) matrix, whose development significantly enhances microbial resistance to antibiotics, disinfectants, and host immune defenses, posing major challenges in clinical, industrial, and environmental settings. Compared with planktonic cells, biofilm-associated microorganisms can exhibit up to 10- to 1000-fold increased tolerance to antimicrobial agents, contributing to the persistence of biofilm-associated infections (BAIs). These infections remain difficult to eradicate due to reduced penetration, altered metabolic states, and the presence of dormant or persister cells. Anti-biofilm strategies can be broadly classified into physical approaches (e.g., ultrasound, mechanical stress, and light-based approaches) that target biofilm structure; chemical and enzymatic methods (e.g., EPS-degrading enzymes) that destabilize the matrix; and biological and molecular strategies (e.g., quorum-sensing (QS) inhibitors, anti-virulence agents, bacteriophages, phage-derived antimicrobial molecules, antimicrobial peptides, and natural bioactive compounds) that modulate biofilm development and integrity by targeting regulatory pathways and matrix stability through distinct mechanisms of action. Natural compounds, including lactoferrin, lactoferrin-derived peptides, and probiotic and postbiotic fractions of lactic acid bacteria (LAB), as well as plant-derived metabolites, have shown promising anti-biofilm effects, with efficacy often enhanced through complementary or potentially synergistic interactions. However, despite these advancements, clinical translation remains limited. For example, BAIs account for approximately 80% of chronic infections, with high recurrence rates and therapeutic failure reported in device-associated infections and chronic wounds. These limitations highlight the need for clinically translatable, multimodal approaches that integrate structural biofilm disruption, antimicrobial targeting, and host response modulation to design more effective and sustainable anti-biofilm strategies. Full article

Cadmium (Cd) is a highly toxic heavy metal that impairs plant growth, metabolism, and the accumulation of bioactive compounds. To investigate methylation-associated Cd responses in the medicinal plant Sophora tonkinensis, we integrated whole-genome bisulfite sequencing (WGBS) and transcriptome sequencing under three Cd treatments (T0, T2, and T4). Cd stress induced extensive transcriptional reprogramming and widespread DNA methylation changes, with CHH methylcytosines accounting for the largest proportion of methylated sites, whereas CG sites showed the highest average methylation level. Differentially methylated regions (DMRs) were predominantly detected in the CHH context and were frequently located in promoter and flanking regions. Integrated analysis identified 6547 and 6204 differentially methylated genes in T2 vs. T0 and T4 vs. T0, respectively, and 420 and 612 genes, respectively, showing concurrent changes in DNA methylation and transcript abundance. Genes with hypermethylation and reduced expression were more frequent than hypomethylated/upregulated genes and were mainly associated with photosynthesis, carbon fixation, fatty acid metabolism, sulfur-related metabolism, and secondary metabolic pathways potentially related to medicinal quality. Among the hypomethylated/upregulated genes, the hormone-related candidate gene StGH3.1 was selected for functional validation, and heterologous overexpression of StGH3.1 enhanced Cd tolerance in transgenic Nicotiana benthamiana. These results indicate that Cd stress is accompanied by coordinated methylome and transcriptome remodeling in S. tonkinensis and provide methylation-associated candidate genes for further investigation of Cd-responsive adaptation. Full article

Mulberry (Morus spp.) is valued for sericulture, medicine, and ecological restoration of degraded lands. Phospholipase A (PLA) enzymes hydrolyze membrane lipids and play critical roles in plant growth and stress responses, yet the PLA family in mulberry remains uncharacterized. Here, we performed genome-wide identification of Morus notabilis PLA genes in order to systematically analyze their phylogenetic relationships and gene structures, and profile their expression across tissues and under drought and salt stress, thereby providing candidate genes for future functional studies on stress tolerance. Fifty non-redundant PLA genes were identified and classified into three subfamilies: pPLA (22), PLA2 (nine), and PLA1 (19). Most predicted PLA proteins are small (100–500 aa) with predicted instability. Gene structures varied from 1 to 21 exons, and subfamily specific conserved domains (patatin/C2, PLATZ, lipase_3) were detected. Promoters contained stress- and hormone-responsive elements. Expression patterns across five tissues revealed distinct preferential patterns: 56% of genes showed highest expression in roots, with one-fifth in leaves. Under stress, 10 and 12 MnPLA genes were increased >2-fold (log₂FC > 1.0) by drought and salt, respectively. Notably, XP_010108435.1 and XP_024022961.1 exhibited leaf-specific high expression and were salt-induced (log₂FC > 1.0); XP_010090405.1 (leaf-specific low) was drought-induced (log₂FC > 1.0); and XP_024023462.1 (root-specific high) was induced by both stresses. These results provide a basis for functional studies and genetic improvement of stress tolerance in mulberry. Full article

Strigolactones (SLs) have emerged as important regulators of plant adaptation to abiotic stress, functioning not as isolated hormones but as integrative signaling molecules. Beyond stress responses, SLs regulate key biological processes, including shoot branching, root architecture, leaf senescence, nutrient acquisition, rhizosphere communication, flowering-related development, and growth–developmental plasticity. This review synthesizes current knowledge on how SLs modulate plant responses to drought, salinity, heavy metal toxicity, high temperature, and low temperature through crosstalk with abscisic acid, auxin, cytokinin, ethylene, and gibberellin. We examine SL structural diversity, biosynthesis, transport, and signaling together with their roles in growth–stress coordination, hormonal networking, and stress-specific mitigation, while distinguishing endogenous SL functions from responses inferred from exogenous analogs such as GR24. Across stresses, SL-mediated resilience converges on adaptive modules, including water regulation, root–shoot architectural remodeling, redox protection, ion and osmotic homeostasis, photosynthetic maintenance, and rhizosphere-assisted resource acquisition. The mechanistic basis involves transcriptional reprogramming, ROS/RNS-linked redox regulation, metabolic protection, and root–microbe interactions. Translational prospects include SL analogs, genetic manipulation, and breeding for adaptive plasticity, nutrient efficiency, and stress tolerance. However, species specificity, dosage dependence, limited field validation, unclear structure–function relationships, and parasitic-weed stimulation remain major constraints. Full article

Copper is an essential trace element for plant growth; however, in excessive amounts, it can cause severe toxicity by inducing bursts of reactive oxygen species and disrupting metabolic balance. As a root-based medicinal plant and food, Platycodon grandiflorus has its roots in direct contact with the soil. Its ability to accumulate copper is the most pronounced among various heavy metals; consequently, it is particularly susceptible to copper stress, which in turn affects its normal growth and medicinal quality. This paper focuses on the intrinsic stress potential and possible response pathways of Platycodon grandiflorus to copper stress. Drawing on existing research and relevant literature, it conducts an integrated analysis of its defence mechanisms across four levels: physical barriers, non-enzymatic antioxidants, conserved physiological and biochemical pathways, and transcriptional regulation. Regarding physical barriers, the cell wall forms the first line of defence through pectin adsorption and lignin deposition; in terms of endogenous antioxidant defence, secondary metabolites such as polysaccharides and saponins can directly participate in the scavenging of reactive oxygen species; regarding conserved pathways, the glutathione–phytochelate system acts in concert with antioxidant enzymes such as SOD and CAT to participate in copper ion chelation and the alleviation of oxidative stress, with hormone signalling regulation also playing a crucial coordinating role in this process; regarding transcriptional regulation, transcription factors such as PgWRKY may mediate the perception of stress signals and the expression of downstream genes. These pathways act in a coordinated and sequential manner, collectively forming a multi-level defence network through which Platycodon grandiflorus responds to copper stress. At the same time, this paper highlights the functional limitations of this defence system, summarises the shortcomings in current research, and proposes directions for future studies, with a view to guiding the safe cultivation and quality assurance of Platycodon grandiflorus in copper-polluted areas, as well as for the breeding of heavy-metal-tolerant medicinal plants. Full article

While Peribacillus simplex has been reported to alleviate abiotic stress-induced damage in diverse plant species, its precise functional mechanism in mediating salt tolerance in asparagus remains unclear. The present study sought to uncover the molecular regulatory mechanisms through which strain P10 enhances the salt adaptability of asparagus seedlings. We investigated physiological responses, as well as transcriptomic and metabolomic alterations, in P10-inoculated asparagus seedlings grown under saline conditions. The results demonstrated that P10 inoculation alleviated salt-induced physiological damage by enhancing antioxidant enzyme activities and promoting the accumulation of osmotic regulatory substances. Comparative transcriptomic and metabolomic analyses identified 1659 differentially expressed genes (DEGs) and 128 differentially accumulated metabolites (DAMs) between P10-inoculated and non-inoculated seedlings under salt stress. These DEGs were primarily associated with multiple biological pathways, including phenylpropanoid biosynthesis, nitrogen metabolism, and flavonoid biosynthesis pathways (flavone, flavonol, and total flavonoid synthesis). Metabolomic profiling indicated that organic acids constituted the most abundant class of DAMs, followed by amino acids and their derivatives, and flavonoids. Integrated transcriptomic and metabolomic analyses suggested that P10 optimized the amino acid metabolic network under salt stress by upregulating genes involved in nitrogen assimilation, glutathione biosynthesis, and polyamine biosynthesis, thereby promoting amino acid accumulation and enhancing glutathione and polyamine levels. In addition, P10 markedly stimulated flavone and flavonol biosynthesis while maintaining elevated anthocyanin levels. Overall, P10 mitigated salt stress injury in asparagus by regulating amino acid metabolism to improve osmotic balance and growth stability, while simultaneously redirecting phenylpropanoid flux toward flavone and flavonol biosynthetic pathways to fine-tune stress responses. Full article

Grafting is a widely used technique to improve stress tolerance in horticultural plants. However, little is known about how grafting affects citrus growth under low-nitrogen (N) stress. To investigate the responses of different grafting combinations to low N availability, we examined root morphology, photosynthesis, chlorophyll fluorescence and semi-quantitative mineral profiles in grafted and ungrafted citrus plants subjected to two N levels (10 and 0.15 mM NO₃⁻ -N) under potted conditions. Analyses were performed on roots and leaves of six plant combinations: ungrafted Trifoliate orange (Poncitrus trifoliata L. Raf., Pt) and red tangerine (Citrus reticulata Blanco, Cr); self-grafted combinations (Pt/Pt and Cr/Cr); and reciprocal heterografts (Pt/Cr and Cr/Pt). Under low-N stress, plant height decreased by 12.3–36.8%, stem diameter by 2.9–31.8%, leaf area by 18.2–26.3%, and SPAD by 11.6–24.5% across the six combinations, with the Cr/Cr combination showing the largest reductions in all parameters. The highest net photosynthetic rate (P_n), intercellular CO₂ concentration (C_i), stomatal conductance (Gs), electron transport rate (ETR), maximum quantum efficiency of PSII (Fv/Fm) and effective quantum efficiency of PSII (Fv’/Fm’) were observed in the Pt and Pt/Pt plants. Low-N stress reduced chloroplastid pigment contents and limited photosynthetic rates. Under 10 mM N treatment, the Fv/Fm values of Pt, Cr, Pt/Pt, and Cr/Pt were approximately 0.82, whereas those of Pt/Cr and Cr/Cr were below 0.82, suggesting lower maximal PSII efficiency in combinations with Cr rootstock. Regarding mineral elements, under low-N stress, the relative levels of P, K, Ca, Mg, and Fe in leaf and root sap increased, while those of N, Cu, Zn, B, and Mn decreased. Overall, combinations with Pt rootstock (Pt/Pt and Cr/Pt) showed better growth and photosynthetic performance, and more stable mineral profiles under low-N stress than combinations with Cr rootstock (Cr/Cr and Pt/Cr). These findings provide a physiological basis for understanding rootstock-specific responses to low-N stress under controlled conditions. Full article

Salt stress is a major abiotic stress that threatens citrus yield and quality. To elucidate the molecular mechanisms underlying differential salt tolerance in citrus rootstocks, we performed an integrative transcriptomic and metabolomic analysis of salt-sensitive trifoliate orange (Poncirus trifoliata) and salt-tolerant Goutoucheng (Citrus aurantium) under 60 mM NaCl treatment for 12 h and 24 h. Physiological observations confirmed that Goutoucheng exhibited less growth inhibition and leaf damage than trifoliate orange. Transcriptome sequencing identified 2081 and 1588 differentially expressed genes (DEGs) in trifoliate orange at 12 h and 24 h, respectively, compared with 1166 and 997 DEGs in Goutoucheng. Metabolome profiling revealed 217 and 173 differentially accumulated metabolites (DAMs) in trifoliate orange versus 162 and 239 DAMs in Goutoucheng at the two time points. KEGG pathway analysis showed that DEGs were mainly enriched in the Mitogen-activated protein kinase (MAPK) signaling pathway—plant, plant hormone signal transduction, and flavonoid biosynthesis—and DAMs were mainly enriched in flavonoid biosynthesis, starch and sucrose metabolism, and glutathione metabolism. Integrative nine-quadrant and two-way orthogonal partial least squares analyses further pinpointed flavonoid biosynthesis as a central hub in salt response. Notably, quercetin derivatives accumulated preferentially in the salt-tolerant rootstock Goutoucheng. Several transcription factor families—including HSF, MYB, NAC, HB-HD-ZIP, C2H2, bHLH, AP2/ERF, and Trihelix—may enhance antioxidant capacity under salt stress by regulating flavonoid accumulation. Collectively, these results indicated that coordinated regulation of flavonoids contributed critically to salt stress adaptation in citrus rootstocks. The identified DEGs, DAMs, and transcription factors provide candidate targets for genetic improvement of salt tolerance in citrus. Full article

This meta-analysis combined the results of 61 independent studies published in 2005–2025 to examine polyamine-mediated responses to aluminum, cadmium, lead, chromium, copper, manganese, and selenium stress in plants. The logarithm ratio of responses (lnRR) under the random-effects model was used to calculate the effect sizes. Polyamine application significantly (p < 0.001) enhanced plant growth, with strong increases in root elongation (lnRR = 0.490, 95% CI: 0.362–0.618), fresh weight (lnRR = 0.413, 95% CI: 0.347–0.480), and dry weight (lnRR = 0.475, 95% CI: 0.409–0.541). Oxidative stress was markedly reduced, as reflected by decreases in reactive oxygen species accumulation (lnRR = −0.585, 95% CI −0.682 to −0.487, p < 0.001), hydrogen peroxide content (lnRR = 0.005, 95% CI −0.244 to 0.254, p = 0.968), and lipid peroxidation (lnRR = −0.487, 95% CI −0.578 to −0.397, p < 0.001). The antioxidant defenses were strengthened, and the levels of superoxide dismutase (lnRR = 0.468, p < 0.001) and catalase activity (lnRR = 0.373, p < 0.001) increased significantly. Metal accumulation was consistently reduced in polyamine-treated plants (lnRR = −0.392, 95% CI −0.460 to −0.324, p < 0.001). Supplementary genetic-level data indicated that metal stress triggers polyamines to regulate metal transporters, polyamine biosynthesis genes, antioxidant-related genes, and hormone-signaling pathways. Collectively, these data points make polyamines a key controller of plant metal stress tolerance and offer a quantitative and mechanistic system to apply them to metal-impacted agroecosystems. Full article

Genetically modified (GM) plants have revolutionized agriculture for more than three decades. The production of a GM plants is a complex, multi-stage process. Several key methods are available for generating GM plants. The choice of transformation method depends on the type of plant (dicotyledonous or monocotyledonous), the objective (large-scale production versus studying a specific gene in particular cells or tissues), and whether stable or transient transformation is desired. Following successful transformation, the next step is the regeneration of a whole plant from a single cell in tissue culture, which is a labor-intensive and time-consuming process. Currently, numerous genes that confer desirable traits have been identified. These traits include stress tolerance, herbicide and pest resistance, and improved consumer qualities (such as flavor, appearance, shelf life, and nutritional value). In this review, we describe the main methods for producing GM plants and provide examples of trait genes utilized in agricultural biotechnology. Despite the fact that GM plants represent one of the most significant biotechnological advances, they also remain among the most contentious issues in contemporary food safety and agricultural policy. Here, we discuss the advantages and disadvantages of using GM plants for humans. Full article

Studies aimed at identifying genotypes tolerant to water deficit are essential for the development of superior plant materials adapted to regions with limited water availability, such as the Brazilian Semi-Arid. This study evaluated the physiological, biochemical, and enzymatic responses of Stylosanthes spp. subjected to different levels of water availability (60%, 40%, and 20% of pot capacity). The experiment was conducted using a completely randomized design using a 3 × 2 factorial scheme, comparing the accession BGF 11-001 and the cultivar BRS-Bela (cv. Bela). Physiological traits, biochemical variables, and antioxidant enzyme activity were analyzed. The accession BGF 11-001 showed resilience under water deficit, maintaining high chlorophyll content even under severe stress. This response was associated with increased accumulation of amino acids such as proline, as well as enhanced antioxidant activity, indicating a tolerance mechanism based on osmotic adjustment and cellular protection. In contrast, cv. Bela exhibited higher sensitivity to water stress, with a pronounced reduction in photosynthetic pigments and greater accumulation of compatible solutes, including total soluble proteins, reducing sugars, amino acids, and proline, without significant activation of antioxidant enzymes. Overall, the results demonstrate that the genotypes adopt distinct strategies to cope with water stress, with BGF 11-001 being more efficient in activating defense mechanisms. Therefore, BGF 11-001 has agronomic potential for cultivation in drought-prone regions and is a promising genetic resource for forage breeding programs aimed at improving drought tolerance. Full article

Water scarcity is increasingly recognized as a slow-onset ecological crisis with major environmental, socio-economic and governance effects, yet systematic assessments of how research on this topic has evolved remain limited. This study addresses this gap through a bibliometric and thematic analysis of water-scarcity publications from 2000 to 2025, using VOSviewer (version 1.6.20), Biblioshiny™ (Bibliometrix version 4.3.1) and RStudio (version 2024.12.1 + 563) to map research trends, conceptual clusters and leading contributing countries, institutions and authors. The analysis shows that water scarcity research is organized around four dominant themes: adaptive water management and climate resilience, plant physiological responses to drought and water stress, ecosystem resilience and biodiversity under water scarcity, and water-limited agriculture and food security. Early scholarship focused heavily on biophysical processes such as drought tolerance and hydraulic conductivity, while recent studies increasingly incorporate socio-ecological, governance and policy dimensions, reflecting a shift toward holistic, solution-oriented approaches. Overall, the study provides a comprehensive overview of the evolution and global distribution of water scarcity research, highlighting the importance of integrating biophysical knowledge with human-centered strategies to support evidence-based decision-making, strengthen inclusive water governance, and enhance socio-ecological resilience in the face of a changing climate. Full article

Increased atmospheric nitrogen (N) deposition and soil salinization commonly co-occur in subtropical economic forests, and responses to these stressors differ between sexes in dioecious plants. In this study, we explored soil chemical and stoichiometric responses of male and female Torreya grandis to N deposition under salt stress by adopting a two-factor completely randomized design. The two factors were (1) plant sex (2-year-old grafted male and female seedlings of T. grandis) and (2) environmental treatment (four nitrogen deposition levels: low, moderate, and high N combined with salt stress, as well as a control without salt addition). We then determined the rhizosphere C, N, P, Ca, K, and Mg concentrations and their stoichiometric ratios. The results showed that all indicators were significantly affected by sex, nitrogen treatment and their interaction (p < 0.0001). Males maintained significantly higher soil C and N levels than females across all treatments, with female soil N and C contents being 5.74–25.72% and 10.78–23.64% lower than those of males, respectively, and exhibiting far more stable stoichiometry. Moderate nitrogen deposition (SMN) increased male C:N, C:P and N:P ratios by 38.76%, 59.75% and 13.84%, distinctly lower than the 85.89%, 98.20% and 16.04% increments in females. In contrast, females had higher Mg content under all salt–nitrogen-combined treatments and greater stoichiometric plasticity, showing a 37.55% higher C:N ratio than males under low nitrogen addition (SLN). Moderate N relieved salt-induced nutrient limitation and alleviated salt-induced P immobilization, while excessive N (SHN) exacerbated stoichiometric imbalance: SHN elevated the N:P ratio by 109.73% in males and only 69.59% in females, narrowing the sexual difference in C:N ratio to 10.92% and triggering severe phosphorus limitation in male rhizosphere soil. Soil–leaf nutrient relationships and correlations differed greatly between sexes, indicating divergent nutrient adaptation strategies. Males adopted a Ca-dominated stress tolerance strategy, and females depended on Mg homeostasis for reproduction. This work provides a scientific basis for sex-specific nutrient regulation and sustainable cultivation of T. grandis under global change. Full article

Dry direct seeding (DDS) is a water-saving and high-efficiency rice cultivation system. However, drought stress during DDS severely constrains seedling establishment. This study used the conventional rice variety Zhonghua 11 (ZH11) and the drought-tolerant hybrid Hanyou 73 to investigate the effects of exogenous silicon (Si) on seed germination and seedling growth under drought stress, and to explore the underlying mechanisms of Si-enhanced drought tolerance. Drought stress was imposed using PEG-6000 simulation and pot experiments with different soil relative water contents (60%, 45%, 25%, and 10%). Si treatment significantly alleviated simulated drought inhibition of seed germination, increasing germination percentage and index, improving seedling growth in both varieties. Under simulated DDS conditions, Si significantly improved plant height, biomass, and root development, while maintaining higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and chlorophyll content. Meanwhile, Si reduced oxidative damage by promoting proline accumulation, enhancing peroxidase (POD) and catalase (CAT) activities in both leaves and roots, reducing malondialdehyde (MDA) accumulation, and upregulating the expression of key drought-responsive genes (SNAC1, DREB1A, SKIPa, P5CS2). Furthermore, Si upregulated the expression of genes involved in abscisic acid (ABA) (ABA1, ABA2, MHZ5, ABI3) and jasmonic acid (JA) (AOS2, AOS3, JAR1, JAR2, MYC2, COI1a) biosynthesis and signaling. Compared with the wild-type, the ABA signaling mutant abi3 and the JA signaling mutant myc2 exhibited significantly attenuated improvement of plant growth by Si treatment. Collectively, Si enhances antioxidant capacity and osmotic adjustment, maintains photosynthetic function, and is associated with the activation of ABA and JA signaling pathways, which together alleviate the inhibition of rice seedling establishment under DDS-associated drought stress. Our findings provide a theoretical basis for the application of Si fertilizer in DDS rice production. Full article