Search Results (101)

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

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

SMXL proteins serve as central regulators of strigolactone (SL) and karrikin (KAR) signaling pathways, orchestrating key developmental processes including shoot branching, floral transition, photomorphogenesis and stress responses. However, the SMXL gene family has not been systematically characterized in Lavandula angustifolia. We identified 37 LaSMXL genes in the lavender genome. Phylogenetic and synteny analyses classified these proteins into four subgroups (Groups I–IV) and indicated that family expansion in lavender was mainly driven by whole-genome and segmental duplications, with most duplicated pairs evolving under strong purifying selection. Gene structure and motif analyses revealed high conservation within each subgroup. Promoter cis-element analysis suggested that LaSMXL genes are integrated into light-, hormone- and stress-responsive regulatory networks. RNA-seq profiling showed that most LaSMXL genes are weakly expressed, but a small subset displays pronounced tissue specificity and clear transcriptional responses to low temperature. Protein–protein interaction predictions and co-expression network analysis further placed highly expressed LaSMXLs within conserved SL/KAR and chloroplast/light-associated modules, alongside D14, KAI2, MAX2, CCD7/CCD8, and CYP711A. Together, these findings provide the first comprehensive overview of the SMXL gene family in lavender and identify candidate LaSMXL genes for future functional studies aimed at optimizing plant architecture and inflorescence-derived essential oil biosynthesis. 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

Phelipanche aegyptiaca is a root parasitic weed that causes severe yield losses in tomato production. Current control methods are constrained by limited efficacy and environmental concerns. Although biocontrol microbes and amino acids have each been reported to suppress broomrape parasitism individually, their synergistic effects and underlying molecular mechanisms remain largely unexplored. This study evaluated the biocontrol performance of Bacillus velezensis strain N35, applied alone or in combination with five amino acids (methionine, isoleucine, valine, histidine, and proline), against P. aegyptiaca parasitism in tomato using pot experiments coupled with transcriptomic profiling of host roots. Both individual and combined treatments significantly reduced the number and fresh weight of P. aegyptiaca parasitic tubercles. Notably, the combinations of methionine + N35 and isoleucine + N35 achieved near-complete suppression of parasitism. Transcriptomic analysis revealed extensive reprogramming of gene expression in tomato roots, with significant enrichment in pathways associated with plant hormone signal transduction, MAPK signaling, phenylpropanoid biosynthesis, and carotenoid biosynthesis. The synergistic treatments coordinately activated ethylene, jasmonic acid, and salicylic acid-mediated signaling, while suppressing auxin and abscisic acid signaling. Moreover, key strigolactone biosynthesis genes (CCD7 and CCD8) were strongly downregulated, and specific genes involved in the biosynthesis of defense-related secondary metabolites were selectively upregulated. Collectively, these findings demonstrate a pronounced synergy between B. velezensis N35 and specific amino acids in suppressing P. aegyptiaca parasitism. This enhanced host resistance is achieved through the coordinated reprogramming of hormonal and metabolic networks, particularly via interference with strigolactone-mediated germination signal secretion. This study provides a theoretical basis for the development of microbe–metabolite synergistic strategies as sustainable and environmentally benign alternatives for broomrape management. Full article

Miscanthus lutarioriparius exhibits strong potential for cadmium (Cd) accumulation, making it a promising candidate for the phytoremediation of Cd-contaminated soils. However, its full remediation potential remains underexploited, highlighting the need for targeted genetic improvement This study presents a comprehensive genome-wide identification and systematic characterization of 20 Ml4CL (4-coumarate: CoA ligase genes) in the M. lutarioriparius. Results indicate that the Ml4CL gene family has undergone substantial evolutionary divergence and expansion. Phylogenetic classification is highly consistent with gene structures ad conserved motifs suggesting potential functional diversification. Promoter analysis revealed a complex cis-regulatory landscape enriched in n ABA- and light-responsive elements, frequently co-occuring with hormone-responsive elements associated with jasmonic acid (JA), gibberellins (GAs), salicylic acid (SA), and strigolactones (SLs) signaling. This pattern suggests that the Ml4CL family may function as an integrative regulatory node linking multiple stress and hormonal signaling pathways. Importantly, under Cd stress, Ml4CL genes exhibited diverse expression dynamics, including gene-specific repression and dose-dependent biphasic responses. Notably, Ml4CL4 showed strong repression, while other members displayed “induction-then-repression” or “repression-then-induction” patterns, suggesting a staged or hierarichical transcriptional response. These findings further suggest that Cd-responsive signaling networks may involve non-linear or threshold-dependent mechanismsthat activate distinct transcriptional programs depending on stress levels. Collectively, this study highlights the regulatory role of the Ml4CL family in plant adaptation to complex environments and identifies candidate dose-resonsive regulatory elements and key allelic variations. These findings provide valuable targets for molecular breeding and synthetic biology aimed at improving crop stress resilience. Full article

The microbial community surrounding plant roots plays a vital role in plant growth, nutrient uptake, stress resilience and other potential functions. This review synthesizes available evidence that plant growth-promoting microorganisms (PGPMs) not only directly benefit the plant but also modulate the rhizospheric microbiome by mediating metabolic reprogramming of the host plant. PGPMs modify the composition of root exudates through the regulation of phytohormone signaling and transcriptional networks, thereby promoting beneficial microbes and suppressing disease. Key mechanisms involve the jasmonate, ethylene, and strigolactones signaling pathways. Transcription factors MYB72, ERF1 regulate biosynthesis and secretion of metabolites like organic acids and coumarins. The exudates serve as specific signals for microbial community assembly and as enhancers of feedback loops that reinforce plant-microbe mutualism. We examine the ecological and agricultural significance of PGPM-induced metabolic reprogramming of the host due to PGPMs that enhances disease suppression, abiotic stress tolerance, and nutrient use efficiency. Lastly, we address advanced methods and strategies for transferring these biological pathways to the agricultural realm and on to a more sustainable agricultural practice with emphasis on the need to integrate multi-omics (whole genomics, transcriptomics, and metabolomics), synthetic microbial communities and plant genetic engineering for microbiome-assisted agriculture. This synthesis reveals that PGPM-induced metabolic reprogramming operates through an integrated cross-scale framework linking microbial perception, phytohormone signaling, transcriptional regulators, and transporter-mediated exudate efflux, with root exudates functioning as plant-controlled ecological filters that selectively shape the rhizosphere microbiome. We further identify key translational challenges, including context-dependent efficacy and the lab-to-field gap, and propose a roadmap combining multi-omics, synthetic communities, and genome editing to realize the potential of microbiome-assisted sustainable agriculture. Full article

Branching traits play a critical role in shaping the tree structure of fruit crops and directly influence both yield and fruit quality. Effective and well-managed branching is crucial for maximizing productivity. However, loquat trees typically exhibit weak branching ability, characterized by fewer and longer bearing shoots, along with terminal flower buds, which collectively result in lower yields per unit area. Despite their significance, research on branching characteristics in loquat remains limited. To clarify the factors influencing branching and to provide a rational and effective direction for improving the inherently weak branching performance of current loquat cultivars, we selected the loquat varieties ‘Dawuxing’ and ‘Chunhua 1’, which exhibit significant differences in leaf and branch growth. Compared to ‘Dawuxing’, ‘Chunhua 1’ has longer branches, wider stem and leaf angles, fewer lateral branches, and a looser leaf cell structure. Transcriptome analysis of terminal buds at different developmental stages revealed that differentially expressed genes in the terminal buds of central branches from the spring and summer shoots of the two cultivars were enriched in the plant hormone signal transduction pathway. Hormone-targeted metabolomics identified significant differences in the levels of abscisic acid, auxins, cytokinins, gibberellins, jasmonic acid, and strigolactones in the terminal buds of both cultivars. Through integrated analysis, two candidate genes were identified as potential regulators of branching differences between the two cultivars: EVM0025028 (EjSAPK1), SnRK2 gene a core component of the abscisic acid signaling pathway, and EVM0040331 (EjRMS3), a D14 gene involved in encoding a strigolactone receptor. These findings provide valuable genetic resources for future research on branching regulation in Eriobotrya species and offer a theoretical foundation for enhancing branching management in loquat cultivation. Full article

Perennial ryegrass is a widely cultivated cool-season forage and turf grass species whose growth and development are limited by drought and high temperature. MAX2 is an F-box leucine-rich repeat (LRR) protein, which serves as a central component of strigolactone (SL) and karrikin (KAR) signaling pathways, involved in multiple growth and developmental processes as well as stress response. Here, we identified LpMAX2, a perennial ryegrass (Lolium perenne L.) homolog of Arabidopsis MAX2 (AtMAX2) and rice D3. LpMAX2 can interact with AtD14 and LpD14 in an SL-dependent manner, implying functional conservation with AtMAX2. Overexpression of LpMAX2 in the Arabidopsis max2-3 mutant partially rescued leaf morphology, hypocotyl elongation, and branching phenotypes, while fully restoring drought tolerance, highlighting the evolutionarily conserved roles of MAX2 in plant growth and drought resistance. In conclusion, LpMAX2 is evolutionarily conserved in SL/KAR signaling pathways, highlighting its potential function in drought adaptation. In addition to elucidating the biological function of LpMAX2, this study identifies a promising genetic target for enhancing stress resilience in forage grasses through biotechnological approaches. Full article

Heat stress caused by global climate change poses a significant threat to agricultural production. Phytohormones, as critical signaling molecules, play pivotal roles in modulating plant responses to heat stress. This review systematically summarizes the molecular mechanisms by which eight phytohormones (auxin, gibberellin, cytokinin, ethylene, abscisic acid, brassinosteroid, salicylic acid, and strigolactone) enhance plant thermotolerance through the regulation of heat shock protein (HSP) expression and function. Specifically, auxin enhances thermotolerance by inducing auxin signaling repressor (Aux/IAA) degradation to upregulate HSP transcription, facilitating the formation of the auxin receptor (TIR1)-HSP90 complex to stabilize TIR1, and forming the auxin exporter (PIN)-HSP22 complex to promote auxin transport. Cytokinin enhances thermotolerance by upregulating HSP transcription, with stronger effects in leaves than roots. Gibberellin, salicylic acid, and ethylene enhance thermotolerance primarily by activating heat shock factor (HSF) to induce HSP transcription. Abscisic acid and brassinosteroid improve thermotolerance by inducing HSP transcription and HSP phosphorylation, while strigolactone acts via D14-mediated upregulation of HSP transcription. These phytohormones collaboratively regulate HSPs, forming an intricate network to enhance plant thermotolerance. Deciphering these mechanisms provides a theoretical framework for developing heat-resistant crops and optimizing cultivation techniques. Full article

Jasmonates (JAs) are crucial phytohormones governing plant growth and defense against stresses. This review synthesizes the intricate molecular mechanisms underlying JA crosstalk with key hormones: auxin (AU), gibberellin (GA), abscisic acid (ABA), ethylene (ET), brassinosteroids (BRs), strigolactones (SLs), and salicylic acid (SA). We focus on interactions during development and stress adaptation, highlighting how these range from synergistic (e.g., JA-ABA/ET in defense, JA-AU in root growth) to antagonistic (e.g., JA-SA in pathogen response, JA-GA/BRs in growth processes). Central to this crosstalk are key regulatory nodes like the MYC2 transcription factor and JAZ repressor proteins, which integrate signals through transcription factor networks, targeted protein degradation, and post-translational modifications. By elucidating these molecular pathways, our review establishes a framework for understanding the complex regulatory logic of hormone interactions. Furthermore, it offers insights for the strategic engineering of hormone signaling (e.g., modulating JAZ stability or MYC2 activity) to enhance crop resilience to environmental challenges. Full article

Abiotic stresses, such as heat, cold, drought, and salt, pose severe challenges to global agriculture, with climate change exacerbating these threats and intensifying risks to crop productivity and food security. Strigolactones (SLs), a class of phytohormones, play pivotal roles in mediating plant development and enhancing stress resilience. This review highlights the multifaceted mechanisms through which SLs regulate plant responses to abiotic stresses, integrating molecular, physiological, biochemical, and morphological dimensions. Molecularly, SLs regulate the expression of stress-responsive genes, such as those encoding antioxidant enzymes and mitogen-activated protein kinase (MAPK), to enhance plant acclimation and survival under abiotic stress conditions. Moreover, genes involved in SL biosynthesis and signaling pathways are indispensable in these processes. Physiologically and biochemically, SLs improve resilience by modulating photosynthesis, stomatal closure, reactive oxygen species (ROS) metabolism, and osmotic adjustment. Morphologically, SLs modulate leaf morphology, shoot development, and root architecture, enhancing plant stress tolerance. Collectively, SLs emerge as key regulators of plant tolerance to abiotic stresses, offering promising strategies for advancing crop improvement and securing agricultural sustainability in the face of climate change. Full article

As sessile organisms, plants adapt to environmental challenges through flexible developmental and physiological programs. Hormones play a central role in this adaptability, integrating environmental signals into coordinated responses that regulate growth and stress tolerance. Comparative studies across photosynthetic lineages reveal that several core hormone functions are remarkably conserved, despite major evolutionary changes in hormone perception, biosynthesis, metabolism, and transport. This conservation suggests that plant hormones have played a pivotal evolutionary role—not only preserving essential biological functions but also enabling increased complexity in plant form and function. A similar dual role is observed in evolutionary endocrinology in animals, where hormones contribute to the emergence and regulation of complex traits. We propose that hormones such as cytokinins, auxins, brassinosteroids, strigolactones, and abscisic acid originated as metabolic derivatives closely tied to core physiological functions essential for survival and reproduction, including reproductive success, nutrient sensing, and dehydration tolerance. Over time, these compounds were progressively integrated into increasingly sophisticated regulatory networks, where they now serve as central coordinators and key targets of evolutionary selection. This model advances our understanding of hormone evolution by providing a structured framework to interpret the persistence, specialization, and integration of plant hormones across evolutionary timescales. Full article