Search Results (171)

Plants are constantly exposed to diverse abiotic stresses, including drought, salinity, and extreme temperatures, which severely limit growth, development, and crop productivity. These stresses disrupt physiological, biochemical, and molecular processes, leading to reduced photosynthesis, altered water and ion homeostasis, and accumulation of reactive oxygen species (ROS). Plants have evolved sophisticated sensing and signaling mechanisms to perceive these stresses, with phytohormones playing central roles in mediating adaptive responses. Key hormones, including abscisic acid (ABA), salicylic acid (SA), jasmonates (JAs), gibberellins (GAs), auxin (IAA), ethylene (ET), melatonin, and strigolactones (SLs), regulate stress tolerance by controlling stomatal behavior, root architecture, antioxidant systems, osmolyte accumulation, and stress-responsive gene expression. Importantly, these hormones operate within an intricate network of crosstalk, integrating multiple signaling pathways to balance growth and stress adaptation. Interactions among ABA, GA, JA, SA, auxin, ET, SLs, and melatonin enable plants to coordinate transcriptional regulation, protein phosphorylation, and ROS signaling, optimizing survival under fluctuating environmental conditions. Understanding the molecular mechanisms underlying hormonal crosstalk and their roles in abiotic stress tolerance provides valuable insights for developing resilient crops in the face of climate change. Full article

Squalene is a triterpene with potent biological activities. Squalene (C₃₀H₅₀) is a linear polyunsaturated hydrocarbon composed of six isoprene units and six carbon–carbon double bonds. It serves as an essential precursor for sterols, steroid hormones, and vitamin D in humans and exhibits antioxidant, anti-tumor, and lipid-regulating properties. In plants, squalene is produced via the mevalonate (MVA) and 2-C-methyl-D-erythritol-4-phosphate (MEP) pathways. The key rate-limiting enzymes in these pathways include 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), farnesyl diphosphate synthase (FPS), and squalene synthase (SQS). Camellia oleifera, a unique woody oil crop native to China, is valued for its high-quality edible oil and as a rich natural source of squalene. This review provides a systematic overview of recent progress in squalene biosynthesis in C. oleifera. It summarizes the structural characteristics and biosynthetic routes. It further elaborates on the multi-level regulatory network modulated by transcription factors (WRKY, bHLH, MYB, and ERF), phytohormones (jasmonic acid, abscisic acid, and gibberellin), and abiotic factors (light and drought). Notably, this review distinguishes earlier foundational studies from recent breakthroughs and integrates emerging progress on squalene’s non-canonical functions and pathway crosstalk. It further highlights novel regulatory mechanisms unique to C. oleifera (e.g., CoWRKY15, CoMYB1, and CoMYC2). By bridging molecular regulation with practical breeding and metabolic engineering, this review lays a solid theoretical foundation for cultivating high-squalene C. oleifera varieties. It represents a prominent innovation relative to previously published studies. Full article

Plants are constantly exposed to a wide range of abiotic stresses that have significant negative impacts on growth and yield. Plant acclimation to these stresses is governed by integrated classical phytohormone and plant peptide hormone signalling networks that control the ability of a plant to survive and adapt to extreme environments. Classical phytohormones, including abscisic acid, auxins, gibberellins, cytokinins, jasmonates, salicylic acid, brassinosteroids, and the recently recognised phytomelatonin, act in concert with peptide-based plant hormones, among which C-terminally encoded peptides (CEPs) play prominent roles in coordinating stress perception, signal transduction, and adaptive responses throughout the plant. These integrated networks control stomatal behaviour, photosynthesis, osmolyte and antioxidant levels, root architecture, and energy metabolism, thereby helping plants maintain homeostasis and optimise survival while sustaining minimal growth under unfavourable conditions. Under stressful conditions, these networks do not operate in isolation but form highly dynamic, context-dependent regulatory circuits in which each physiological process is simultaneously regulated by multiple hormones acting through convergent and overlapping signalling pathways. Phytomelatonin has emerged as a particularly important integrative node within these networks, functioning both as a potent direct antioxidant through sequential ROS-scavenging catabolite cascades and as a bidirectional regulator of classical phytohormone signalling under diverse abiotic stresses. New technologies in the fields of transcriptomics, proteomics, phosphoproteomics, metabolomics, and systems biology have provided new information on the dynamic relationships between classical phytohormones and plant peptide hormones, revealing candidate regulatory nodes and transcription factor networks that mediate stress adaptation at molecular, biochemical, and physiological levels. However, it is important to distinguish between correlative associations identified through omics profiling and causal regulatory relationships validated through rigorous genetic and biochemical experimentation, as most omics-derived candidates remain to be functionally established. Empirical studies demonstrate how these networks can be used to improve crops by increasing stress tolerance through modulating classical phytohormone and plant peptide hormone signalling, including through exogenous phytomelatonin application, CRISPR-mediated hormone pathway editing, and CEP pathway manipulation, to produce resilient cultivars without reducing yields. Although these advances represent significant progress, challenges remain, including the inherent complexity and redundancy of the networks, context-dependence and severity-dependence of hormonal responses, the persistence of a significant translational gap between laboratory findings and field application, and incomplete mechanistic understanding of peptide hormone roles under combined stress conditions. Addressing these challenges will require integrative multi-omics approaches, higher-order computational modelling, and rigorous field-based functional validation alongside emerging tools such as synthetic biology and precision breeding. Full article

Cold stress (CS) represents a major environmental factor that adversely affects plant growth, development, and productivity. To cope with low-temperature conditions, plants have evolved sophisticated mechanisms for CS perception and response, mediated through complex cellular signaling networks and physiological processes. Central to these adaptive responses are phytohormones, which function either independently or through synergistic and antagonistic interactions to fine-tune CS tolerance. This review synthesizes current knowledge on the roles of major classical phytohormones and signaling metabolites in regulating CS tolerance in plants. We first outline the molecular mechanisms involved in CS sensing and signal transduction, highlighting the roles of membrane-associated sensors, calcium signaling, and downstream transcriptional networks. Then, we discuss the contributions of key classical phytohormones, including auxin, abscisic acid, ethylene, salicylic acid, cytokinin, jasmonic acid, brassinosteroids, gibberellic acid, strigolactones, and signaling metabolites, including melatonin and gamma-aminobutyric acid, to CS tolerance, highlighting their individual and interacting roles in modulating gene expression regulation, antioxidant defense and physiological adaptations. We also discuss the crosstalk between these hormones, emphasizing the dynamic and often context-dependent nature of their interactions in response to CS. Furthermore, the review highlights recent advances in CRISPR/Cas9-based genome editing strategies targeting phytohormone biosynthesis, signaling, and response pathways to improve CS tolerance in plants. By integrating hormonal signaling, molecular regulation, and modern biotechnological tools, this review provides a comprehensive framework for understanding phytohormone-mediated CS adaptation and offers perspectives for developing climate-resilient crops through genetic and agronomic approaches. Full article

In recent years, plant stress biology has moved beyond single-pathway descriptions toward an integrated framework in which stress perception, hormonal control, and gene regulation are tightly interconnected. Early events such as membrane-associated sensing, calcium influx, reactive oxygen species (ROS) generation, and kinase activation converge with phytohormonal networks to shape context-dependent responses. Within this framework, abscisic acid, salicylic acid, jasmonates, ethylene, auxin, cytokinins, gibberellins, brassinosteroids, and strigolactones function not as isolated regulators but as components of a dynamic signaling matrix that balances survival, defense, growth restraint, and recovery. These hormonal signals are ultimately translated into adaptive outcomes through extensive transcriptional and post-transcriptional reprogramming mediated by transcription factors, RNA-based regulators, chromatin remodeling, and stress memory mechanisms. This review synthesizes current understanding of how plants integrate stress perception, phytohormonal crosstalk, and transcriptional regulation to establish stress tolerance. We first examine the molecular basis of stress sensing and early signaling. We then discuss the central functions of major phytohormones and the logic of hormone–hormone interaction networks in coordinating stress adaptation. Next, we analyze transcriptional, post-transcriptional, and epigenetic mechanisms that determine response specificity, intensity, and persistence. We further highlight points of convergence between abiotic and biotic stress responses and discuss how combined stresses challenge traditional single-stress models. Finally, we consider the roles of omics, systems biology, and translational technologies in decoding and engineering stress-resilient phenotypes. By integrating these perspectives, this review presents plant stress tolerance as a multilevel systems property and outlines key priorities for future research aimed at developing climate-resilient crops. Full article

Nitrogen is a critical macronutrient for plants, playing a central role in the synthesis of proteins, amino acids, and nucleic acids. To enhance nitrogen use efficiency (NUE) and ensure sustainable agricultural production, identification of nitrogen-efficient genes and application of molecular breeding techniques are crucial for developing high-NUE rice germplasm. The nitrogen signaling pathway exhibits close crosstalk with phytohormones, including auxins (IAA), gibberellins (GAs), abscisic acid (ABA), cytokinins (CTKs), brassinosteroids (BRs), and strigolactones (SLs). This review systematically summarizes the molecular mechanisms underlying crosstalk between nitrogen and phytohormones, focusing on the physiological and molecular basis underlying their synergistic regulation of root development and NUE in rice, and outlines challenges for the complicated research field and prospective directions in future. Full article

Plants in agricultural systems rarely face single stressors; instead, they encounter concurrent biotic (pathogen, pests) and abiotic (drought, salinity, heavy metals) stresses that causes severely reduce crop yields and endanger food security. The traditional methods of breeding, genetic engineering, and agrochemicals tend to target individual stresses and still do not suffice in the complex field conditions. Compared to these approaches, nanotechnology offers distinct advantages: nanoparticles (NPs) can be applied as foliar sprays or seed treatments without lengthy breeding cycles or regulatory hurdles associated with genetically modified organisms. However, nanotechnology is not inherently “better” but rather complementary to crop engineering; each approach has specific strengths. Breeding and genetic engineering provide heritable, long-term solutions, while nanotechnology offers immediate, season-specific, and reversible interventions. Cross-tolerance, the phenomenon whereby exposure to one stress enhances tolerance to another, offers a promising alternative. This review critically examines how NPs act as stress-priming agents that induce cross-tolerance by activating overlapping defense networks, including antioxidant systems (SOD, CAT, APX), phytohormonal crosstalk (ABA, SA, JA), osmolyte homeostasis, and stress-responsive gene expression. We synthesize current evidence on NP uptake, translocation, and cellular interactions, and evaluate their dual role in directly suppressing pathogens while simultaneously enhancing plant immune responses and physiological resilience. However, efficacy is highly dose-dependent: low, subtoxic doses prime defense through hermetic ROS signaling, whereas supraoptimal doses cause phytotoxicity. The current challenges in nano-mediated stress alleviation include: (i) a persistent laboratory-to-field translation gap, with field outcomes averaging only 60–70% of greenhouse efficacy; (ii) dose-dependent phytotoxicity; (iii) poor reproducibility across studies; (iv) scalability and formulation stability issues; and (v) insufficient understanding of long-term environmental fate, including soil accumulation, non-target organism effects, and food chain safety. Future research should consider field-validated formulations (e.g., SiNPs, ZnONPs, Fe₃O₄NPs) across major staple crops); integrating nanotechnology with precision agriculture through nanosensors, remote sensing, and artificial intelligence for site-specific, dose-optimized applications;developing smart, biodegradable nanoparticles with stimuli-responsive release; and establishing harmonized regulatory frameworks for nano-agrochemical approval. When deployed responsibly, nanoparticle-induced cross-tolerance represents a sustainable approach to improve crop resistance against multifactorial stress, with significant implications for climate-resilient agriculture and global food security. Full article

Abscisic acid (ABA) regulates diverse aspects of plant growth and secondary metabolism, yet its concentration-dependent effects on rhizomatous spice crops remain poorly understood at the systems level. Here, we investigated the phenotypic, physiological, hormonal, and multi-omics responses of ginger (Zingiber officinale) to foliar-applied ABA across a concentration gradient. Exogenous ABA modulated ginger growth in a distinctly non-linear manner. Low-to-moderate concentrations (5–15 mg/L) significantly enhanced aboveground branching and belowground rhizome yield, whereas high concentration (35 mg/L) inhibited branching while promoting structural carbohydrate accumulation, revealing a concentration-dependent trade-off between growth and secondary wall deposition. Hormone profiling uncovered global reprogramming of the endogenous hormonal network, with optimal ABA (15 mg/L) coordinately elevating growth-promoting hormones and defense-related signals, while high concentrations suppressed multiple hormone pathways and triggered negative feedback inhibition of endogenous ABA biosynthesis. Integrated metabolomic and transcriptomic analyses identified convergent enrichment on phenylpropanoid biosynthesis, gingerol biosynthesis, and plant hormone signal transduction. Co-expression network analysis revealed a highly interconnected module of 583 genes linking hormone signaling to secondary metabolism, with coordinated up-regulation of key enzymes from phenylalanine ammonia-lyase (PAL) to polyketide synthase under 15 mg/L ABA explaining the 64% increase in 6-gingerol content. This study establishes a mechanistic chain from ABA perception to improved ginger yield and quality, mediated by hormonal crosstalk and transcriptional activation of the phenylpropanoid-gingerol network. We propose an “ABA optimization window” of 5–15 mg/L for precision cultivation of high-quality ginger, providing a systems-level framework for understanding hormone-mediated regulation of secondary metabolism in medicinal and spice crops. Full article

Abiotic stresses severely constrain crop productivity by disrupting cellular redox homeostasis and hormone signaling. Although individual stresses differ in origin, plant responses converge on a conserved regulatory system centered on reactive oxygen species (ROS) and phytohormone crosstalk. Controlled ROS production in chloroplasts, mitochondria and the apoplast functions as a signaling mechanism that interacts dynamically with abscisic acid, auxin, ethylene, jasmonate and cytokinin pathways through shared regulatory nodes, including nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and redox-sensitive transcriptional cascades. Endogenous metabolites, including phenolics, terpenoids, carotenoids, alkaloids, polyamines, glutathione and signaling peptides, are embedded within this network and modulate its amplitude and sensitivity. In parallel, non-microbial biostimulants derived from seaweeds, higher plants, protein hydrolysates and humic substances have been widely reported to enhance crop performance under abiotic stress. However, mechanistic integration between biostimulant research and plant stress signaling remains limited. In this review, we propose that terrestrial plant- and algal-derived biostimulants act not as external substitutes for hormones or antioxidants but as modulators of endogenous ROS–hormone signaling hubs. We first synthesize the current understanding of redox–hormone integration under abiotic stress, then examine endogenous metabolites as intrinsic regulators of this network, followed by an analysis of biostimulants in relation to shared regulatory nodes. By positioning biostimulant action within the established redox–hormone network, we provide a mechanistic framework that links stress biology with agronomic application and supports rational strategies to enhance crop resilience. Full article

Fungal endophytes are microorganisms that inhabit plant tissues without causing disease and emerge as critical mediators of plant stress tolerance, nutrient acquisition, and ecosystem resilience under diverse climate change scenarios. Their unique position within the host allows them to modulate physiological responses more closely than external microbiota. This review explores how endophytic fungi contribute to plant adaptation under climate-induced stresses such as heat, salinity, drought, pollution, and nutrient limitation, with a focus on molecular crosstalk, functional trait modules, and metabolic trade-offs. Key findings emphasize multilayered signaling systems, including MAMP/DAMP recognition, phytohormone regulation, immune tuning, ROS dynamics, and effector deployment, while emerging mechanisms such as cross-kingdom RNA and extracellular vesicle (EV)-mediated exchange are discussed as promising but currently limited in empirical validation within many endophytic systems. Endophytes also enhance nutrient exchange through conditional carbon-for-benefit trade and may shape rhizosphere microbiota and soil activities through plant-mediated inputs. Integrative multi-omics approaches provide predominantly correlational insights into the mechanistic basis of these effects, linking molecular function to ecosystem and community outcomes. These insights have potential applications in climate-resilient agriculture, phytoremediation, and ecosystem restoration; however, their large-scale implementation requires further field-based validation and context-specific assessment. Future priorities should focus on trait-based selection, ecological modeling, and biosafety evaluation to translate microbial functions into reliable field-level strategies that support sustainable crop performance under accelerating environmental stress. Full article

Abiotic stresses including drought, salinity, heat, cold, and heavy metal toxicity severely constrain plant productivity worldwide. Nitrogen (N), beyond its fundamental nutritional role, has emerged as a central regulator of plant stress responses through its involvement in metabolic reprogramming, osmotic adjustment, antioxidant defense, and hormonal signaling. This review synthesizes current advances in understanding how nitrogen availability and form influence plant tolerance to major abiotic stresses. Particular emphasis is placed on nitrogen-mediated modulation of reactive oxygen species (ROS) scavenging systems, nitrogen–carbon metabolic coordination, phytohormonal crosstalk, osmoprotectant biosynthesis, and regulation of stress-responsive gene expression. Recent molecular insights highlight the role of nitrogen transporters, nitrate signaling pathways, and nitrogen-use efficiency in stress adaptation mechanisms. Furthermore, agronomic and biotechnological strategies aimed at optimizing nitrogen management to enhance stress resilience are discussed, including precision fertilization, integrated nutrient management, and genetic approaches targeting nitrogen-responsive regulatory networks. By integrating physiological, biochemical, and molecular perspectives, this review provides a comprehensive framework for understanding nitrogen-driven mitigation strategies under abiotic stress conditions and outlines future research directions for sustainable crop production in changing environments. Full article

Sorghum (Sorghum bicolor L.) is a vital crop for both grain production and forage, playing a critical role in ensuring global food security and sustainable livestock production. Drought stress represents one of the most severe abiotic constraints in sorghum cultivation, adversely affecting plant growth and development, and ultimately leading to significant reductions in yield and quality. Melatonin has emerged as a multifaceted plant growth regulator that enhances plant growth and confers tolerance to various abiotic stresses. It actively participates in regulating key physiological processes, including seed germination, seedling establishment, cellular development, and metabolic homeostasis. This review synthesizes current knowledge on the impacts of drought stress on sorghum growth and physiological metabolism, with a specific focus on the protective role of melatonin under water-deficit conditions. The underlying physiological and molecular mechanisms are comprehensively discussed, encompassing ion homeostasis, nutrient metabolism, reactive oxygen species (ROS) scavenging, photosynthetic efficiency, energy metabolism, phytohormone crosstalk, signal transduction, and associated gene expression. Finally, we outline future research directions to advance our understanding of melatonin-mediated drought tolerance in sorghum, providing insights for breeding drought-resilient varieties and developing high-yielding cultivation strategies. Full article

Around 85% of all land plants have symbiotic relationships with arbuscular mycorrhizal (AM) fungi, microscopic soil fungi that build extensive filamentous network in and around the roots. These links strongly influence plant development, water uptake, mineral nutrition, and defense against abiotic stresses. In this context, the use of AMF as a biological instrument to enhance plant drought resistance and phenotypic plasticity, through the formation of mutualistic associations, seems like a novel strategy for sustainable agriculture. This review synthesizes current understanding on the mechanisms through which AMF alleviates drought stress in agriculture. We focus on how AMF help maintain nutrient and water homeostasis by modulating phytohormones and signaling molecules, and by orchestrating associated biochemical and physiological responses. Particular emphasis is placed on aquaporins (AQPs) as key water-and stress-related channels whose expression and activity are modulated by AMF to maintain ion, nutrient, and water balance. AMF-mediated host AQP responses exhibit three unique patterns under stressful conditions: either no changes, downregulation to limit water loss, or upregulation to promote water and nutrient uptake. Nevertheless, little is known about cellular and molecular underpinnings of AMF effect on host AQPs. We also summarize evidence that AMF enhance antioxidant defenses, osmotic adjustment, soil structure, and water retention, thereby jointly improving plant drought tolerance. This review concludes by outlining the potential of AMF to support sustainable agriculture, offering critical research gaps, such as mechanistic studies on fungal AQPs, hormonal crosstalk, and field-scale performance, which propose future directions for deploying AMF in drought-prone agroecosystems. Full article

The grain-filling stage is crucial for determining yield and quality in rice. This process, and the pronounced disparity in development between superior and inferior grains, is orchestrated by a dynamic network of endogenous phytohormones. However, an integrated synthesis of their synthesis, transport, signaling, and crosstalk—particularly in the context of modern high-yield cultivation—is lacking. This review comprehensively analyzes the roles of auxin, cytokinin, gibberellin, abscisic acid, ethylene, brassinosteroids, and polyamines, with emphasis on their spatiotemporal dynamics and interactions in shaping grain fate. We explicitly link these hormonal mechanisms to agronomic and chemical regulation practices, such as nitrogen management and alternate wetting-drying irrigation. By synthesizing this knowledge, we aim to propose a unified model of grain filling regulation. This framework provides an actionable theoretical foundation for designing precise strategies to manipulate hormonal balances, thereby improving grain filling uniformity, yield, and quality in rice. Full article

Ratoon rice cultivation is an efficient production system that achieves a second harvest from the stubble of the main crop, but its yield potential is largely constrained by variation in axillary bud regeneration capacity. Here, we identify OsPM19L, a plasma membrane–localized AWPM-19 domain protein, as a key regulator of rice ratooning ability. Transcriptome analysis revealed higher OsPM19L expression in strong-regeneration cultivars, followed by a sharp decline after harvest. Promoter assays and hormonal treatments demonstrated that OsPM19L is strongly induced by ABA and functions as a positive regulator in ABA signaling. Under field conditions, ospm19l mutants exhibited increased tiller number but reduced ratooning index, whereas OsPM19L-OE plants showed the opposite pattern, indicating stage-specific regulation of tillering and regeneration. Hormone profiling and gene expression analyses showed that OsPM19L is associated with altered levels of multiple phytohormones in regenerating axillary buds, showing higher CK and GA levels and lower IAA and ABA levels in OsPM19L-OE compared with the wild type. Consequently, OsPM19L appears to facilitate dormancy release and enhance early axillary bud growth during the ratoon season. These findings indicate OsPM19L may act as a central regulator linking ABA signaling with hormonal cross-talk, providing new insights into the molecular control of regeneration and potential targets for improving ratoon rice productivity. Full article