Search Results (536)

The symbiotic relationship between soybean and rhizobia facilitates nodulation and nitrogen fixation, providing a sustainable nutrient supply for increasing crop yields and reducing chemical fertilizer use. However, comparative studies on the conservation and strain-specificity of host gene expression regulated by different rhizobial strains remain limited. Here, we performed a comparative analysis between the previously isolated strain, Bradyrhizobium ottawaense Bott 59, and the model strain, Bradyrhizobium diazoefficiens USDA 110. Symbiotic phenotypes were evaluated after inoculation, and a root transcriptomic analysis was conducted at 3 dpi to assess early molecular responses. At 21 dpi, Bott 59-inoculated plants outperformed plants inoculated with USDA 110 in nodule number, nitrogenase activity, and biomass. Transcriptomic analysis revealed conserved host responses to both rhizobial strains, including NIN-mediated signaling, AON signaling, and the biosynthesis of phenylpropanoids and brassinosteroids. Further analysis revealed that Bott 59 specifically induced the expression of genes involved in isoflavonoid and flavonoid biosynthesis, including those encoding I2H, and HI4OMT. Moreover, Bott 59 triggered more pronounced transcriptional reprogramming in auxin, cytokinin, and jasmonic acid signaling pathways, along with differential expression of a broader set of transcription factor genes. Collectively, this study systematically unravels the conserved and strain-specific transcriptional regulatory events underlying host–rhizobium interactions. Our findings provide valuable theoretical insights and transcriptomic resources for further dissecting the molecular mechanisms of symbiotic nitrogen fixation (SNF), as well as for the targeted genetic improvement of crop nodulation and nitrogen fixation efficiency. Full article

Knot-free timber production in Cunninghamia lanceolata depends critically on internodal characteristics, yet the mechanisms governing internode elongation remain poorly understood, hindering breeding efforts for longer-internode varieties. In this study, we selected two clones with distinct internodal traits (the C1 clone exhibited a 25.03% longer internodal length than the C11 clone) as materials. Enzyme-linked immunosorbent assay (ELISA) and RNA sequencing were used to investigate dynamics in endogenous hormones and transcriptional regulation in internodal growth. Results showed that the difference in indole-3-acetic acid (IAA) rhythms in apical buds is a key factor of C1’s longer internodal growth; higher levels of IAA and cytokinins in the apical buds of C1 may support sustained internodal growth; upregulated IAA-related genes in upper phloem (PIN1 and SAURs), which are involved in polar transport and signal response, indicates a stronger capacity to establish apical dominance. Hormone transport may be regulated by very long-chain fatty acids (VLCFAs). Consistent with reduced brassinosteroid activity, genes involved in VLCFA biosynthesis and transport were generally lower in C1, implying excessive VLCFA accumulation in C11 may be negative to IAA transporting and internode growth. This study offers a preliminary insight into internodal growth mechanisms influenced by hormone biosynthesis and transport in C. lanceolata., providing a basis for genetic improvement, germplasm selection, and exogenous hormone applications in knot-free timber cultivation. Full article

Phytohormones, or plant hormones, are intrinsic organic compounds within plants. These compounds have a significant impact as essential plant growth and development regulators, influencing processes from seed germination to fruit ripening. The exogenous application of these phytohormones, such as gibberellic acid (GA₃), indole-3-acetic acid (IAA), and brassinosteroids, has been shown to significantly enhance horticultural productivity, with reported increases in germination, growth, and yield ranging from 10–40%. These signaling molecules are also vital for micro and macroalgae development and functioning. Recognizing their presence within algae presents a fresh perspective for horticultural researchers and cultivators, offering opportunities to enhance the quality and application of horticultural crops. Nevertheless, the challenge arises from the presence of phytohormones in trace amounts, complicating their extraction and identification. This paper will offer a comprehensive overview of phytohormone classification and detection methods and highlight their presence in algae, which may serve as an alternative for promoting plant growth in agriculture. 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

Low temperatures severely restrict tea plant (Camellia sinensis) growth and yield stability, yet how brassinosteroid (BR) signaling modulates cold acclimation at a systems level remains insufficiently defined. Here, we integrated transcriptomic and UHPLC–MS metabolomic profiling of tea leaves under Control, 24-epibrassinolide (EBR), Cold, and Cold + EBR treatments to delineate BR-potentiated cold responses. Principal component analyses revealed clear treatment-specific separation and tight clustering of biological replicates at both omics levels. Quantitatively, cold stress induced extensive reprogramming (4075 differentially expressed genes (DEGs) and 298 differentially accumulated metabolites (DAMs)), whereas EBR alone exerted relatively modest effects (231 DEGs and 50 DAMs). Notably, EBR under cold conditions further reshaped cold-responsive networks (371 BR-modulated DEGs and 17 BR-modulated DAMs), consistent with a potentiating role for BR signaling. Functional enrichment analyses highlighted phenylpropanoid metabolism and hormone signal transduction as core responsive modules, with coordinated activation of key gateway genes (PAL, C4H, and 4CL) and concurrent engagement of lignin-, flavonoid-, and catechin-associated branches under Cold + EBR. Metabolomic analyses identified flavonoids as the dominant responsive metabolite class (49.31%), particularly anthocyanins and flavonol glycosides. Integrative TF–metabolite–gene correlation networks prioritized WRKY transcription factors (TEA001162, TEA027058) and a UDP-glycosyltransferase gene (TEA025792) as candidate hub genes linking hormone signaling to phenylpropanoid outputs. Collectively, this work provides a systems-level framework of co-regulated transcript–metabolite modules and candidate molecular targets, offering a foundation for functional validation and practical improvement of cold resilience in tea production. Full article

Cadmium (Cd) contamination is widely recognized as a major risk factor affecting the security and quality of crop production. Watermelon (Citrullus lanatus) is a globally cultivated fruit that is susceptible to Cd stress. 24-Epibrassinolide (EBR), an active brassinosteroid, is essential for plant growth and abiotic stress responses. However, its protective role in watermelon under Cd stress remains unclear. This study elucidates the physiological and molecular processes underlying EBR-mediated alleviation of Cd toxicity in watermelon seedlings. The results showed that exogenous EBR application effectively mitigated Cd-induced growth inhibition through decreased Cd deposition, reduced the accumulation of reactive oxygen species (ROS), lowered membrane lipid peroxidation, and increased antioxidant capacity in watermelon leaves under Cd treatment. Transcriptome (RNA-Seq) analysis revealed that EBR triggered substantial reprogramming of gene expression patterns, identifying 530 differentially expressed genes (DEGs) in Cd + EBR co-treatment compared with Cd treatment alone, including 204 down-regulated genes and 326 up-regulated genes. These DEGs are vital for controlling several physiological processes, including phenylpropane metabolism, phenylpropanoid biosynthesis, endoplasmic reticulum’s protein production, cell wall organization, and others. Further physiological assays confirmed that EBR increased the activities of PAL and 4CL, the core enzymes driving phenylpropanoid biosynthesis, leading to a significant accumulation of total phenols and flavonoids. Together, the above results give concrete proof of the powerful functions of 24-EBR, acting as an enhancer of plant performance under Cd stress by enhancing the antioxidant system and by activating the phenylpropanoid pathway and its derived metabolic networks. Full article

Cadmium (Cd) accumulation in plant tissues causes several damages, including disturbances in anatomical structures, negative impacts on photochemical reactions, and reducing the efficiency of the photosynthetic apparatus. 24-Epibrassinolide (EBR) is a plant steroid that regulates multiple physiological and biochemical processes to counteract the harmful effects of metal stress. The aim of this research was to investigate whether exogenous EBR application affects leaf and root anatomical structures, including stomatal responses, redox-metabolism-related biochemical responses intrinsically related to photosynthetic apparatus, and nutritional status in soybean plants under Cd excess. The experiment was randomized with four treatments: two cadmium concentrations (0 and 500 µM Cd, described as −Cd and +Cd, respectively) and two EBR levels (0 and 100 nM EBR, described as −EBR and +EBR, respectively). Results demonstrated that EBR positively regulated root and leaf structures and stomatal performance, with significant increases in epidermis and cortex (root) and benefits for spongy parenchyma and stomatal density (leaf), clearly protecting the photosynthetic apparatus against Cd excess. Simultaneously, this steroid mitigated Cd-induced oxidative stress by stimulating the activities of superoxide dismutase (25%), catalase (28%), ascorbate peroxidase (30%) and peroxidase (48%), while simultaneously reducing the content of oxidative compounds, including superoxide (16%), hydrogen peroxide (8%), malondialdehyde (12%) and electrolyte leakage (14%). The dual mechanism modulated by EBR protected anatomical structures and stimulated antioxidant defense. Therefore, the results prove that exogenous EBR application effectively attenuates the adverse effects of Cd excess in soybean plants. Full article

Stressful effects on agriculture are of paramount importance in the 21st century. Water deficiency is considered a major constraint in crop succession, particularly for maize. Therefore, this study aimed to investigate the potential roles of brassinolide (BL) and silicon (Si) in mitigating biotic (incidence of pests and diseases) and abiotic stresses (naturally occurring water deficit) in maize grown after soybean harvest. The field experiments were conducted over two growing seasons on a Rhodic Haplustox in the Cerrado, Goiás, Brazil. A randomized complete block design was employed in a 5 × 2 factorial arrangement, with five BL doses (0.000, 0.050, 0.100, 0.150, and 0.200 mg L⁻¹) and two Si treatments (absence and presence), each with four replicates. BL was applied immediately when the soil moisture in the 0–0.20 m layer reached 16.25%, corresponding to the crop’s critical water threshold. This specific phenological point corresponded to the R₂ stage in the first off-season and the V₁₀ stage in the second off-season. Si applications were performed at the V₃ and V₈ stages. BL application enhanced growth, as well as physiological and metabolic performance by increasing protein synthesis and sugar content, thereby maintaining relative water content, sustaining antioxidant enzyme activity, and reducing lipid peroxidation under water-deficit conditions. The BL doses that achieved the highest yields were 0.149 mg L⁻¹ (R₂ stage) in the first off-season and 0.134 mg L⁻¹ (V₁₀ stage) in the second off-season. Si application effectively reduced pest damage and disease severity while improving plant water status. However, in the second off-season, a significant BL × Si interaction was limited to carotenoids, pheophytinization index, and disease severity. These results indicate that the combined use of BL and Si provides a promising strategy to enhance maize resilience by integrating BL-mediated yield promotion with Si-driven physical and biotic protection under adverse environmental conditions. Full article

While “survival of the fittest” implies that competition is the main driver of evolution, cooperation and altruism are also widespread in nature, even among plants. This suggests that natural selection favors regulatory systems that balance competitive growth with restraint, depending on context. We propose that plant hormones are key mediators of this balance, acting along a spectrum from competition to cooperation. Based on evidence from developmental, ecological, and evolutionary studies, we classify major plant hormones by their roles in competitive behavior: auxin, gibberellins, and brassinosteroids drive competitive foraging and resource acquisition, while cytokinins, abscisic acid, strigolactones, ethylene, salicylic acid, and jasmonate are linked to growth restraint, resource conservation, and communal defense. This functional partitioning reflects a modular hormonal architecture that allows plants to adapt flexibly to their environment and social context. We explore how this classification could inform the use of plant hormones in agriculture and advance research in plant kin selection and inclusive fitness. Full article

Bacterial wilt caused by Ralstonia solanacearum is a major constraint on tomato (Solanum lycopersicum L.) production, yet the molecular basis of quantitative resistance remains poorly understood. In this study, comparative transcriptome profiling was performed on resistant (‘ZM3’) and susceptible (‘ZM86’) tomato inbred lines following pathogen inoculation in roots, stems, and leaves. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were conducted to identify resistance-associated regulatory modules and hub genes. The results revealed distinct gene expression patterns between the two genotypes after infection. Several co-expression modules were significantly associated with resistance or susceptibility traits. Functional enrichment analysis showed that differentially expressed genes were mainly involved in plant hormone signal transduction, plant–pathogen interaction, phenylpropanoid biosynthesis, and cell wall modification. Genes related to ethylene and salicylic acid signaling were strongly induced following infection, whereas brassinosteroid-associated genes showed genotype-dependent expression patterns. Network analysis further identified several hub genes within defense-related modules, including ACO (Solyc04g007980), ERF1 (Solyc09g091950), MAPK9, receptor-like kinase RLK (Solyc07g006770), and a dirigent family gene (Solyc10g008900). Taken together, our results suggest that tomato resistance to Ralstonia solanacearum involves a coordinated defense network integrating hormone-mediated transcriptional regulation and structural reinforcement, and provides candidate genes for breeding bacterial wilt-resistant cultivars. Full article

Sweet cherry (Prunus avium L.) is a highly appreciated fruit species for consumption but susceptible to climate change-induced weather, such as heavy rainfall, which catastrophically compromises yield and commercial fruit quality. Brassinosteroids (BRs) represent a novel biologically safe class of hormones that have been shown to increase plant resilience against these adversities and enhance crop yield and fruit quality in some fruit species. The main aim of this study was to evaluate the potential efficacy of the preharvest foliar spray treatments with 24-epibrassinolide (24-BL) at 0.01, 0.1 and 1 µM on crop yield, cracking incidence and fruit quality of ‘Sunburst’ and ‘Skeena’ sweet cherry cultivars, during two seasons with different weather conditions (2022 and 2023). Results revealed that 24-BL treatments improved fruit growth, fruit weight, and increased commercial crop yield, especially at 0.1 µM during the first season. Notably, in 2023, when extreme rainfall occurred, 24-BL at 0.01 and 0.1 µM significantly decreased cracking incidence by up to 50% for ‘Skeena’. Additionally, firmness, red colour and bioactive compounds, such as total phenolics and total anthocyanins, were also found at higher levels in fruits from 24-BL-treated trees compared to controls, in both cultivars and years. In conclusion, the foliar spray application of 24-BL at 0.01 µM and, especially at 0.1 µM, can be a useful and eco-friendly tool to reduce cracking incidence, improve crop yield and enhance sweet cherry quality traits regardless of environmental negative events, such as heavy rainfall. Importantly, the enhancement of bioactive compounds would promote additional antioxidant properties and enhance health benefits to consumers. Full article

Background/Objectives: Floral bud morphogenesis is a critical developmental process determining yield potential in blueberry, yet the molecular regulatory mechanisms in leaves during this phase remain poorly understood. Methods: In this study, we employed a time-series transcriptomic approach to investigate leaf gene expression dynamics during floral bud morphogenesis in rabbiteye blueberry. Leaves were sampled at six time points spanning the critical developmental window from the cessation of summer shoot growth to bud swell and dormancy onset. Results: RNA-seq analysis generated 121.68 Gb of clean data, and weighted gene co-expression network analysis (WGCNA) identified four stage-specific modules (brown, red, blue, turquoise) significantly associated with distinct morphogenetic phases. The brown module (0–6W) was enriched in photosynthesis and hormone signaling pathways, while the red (9W) and blue (12W) modules featured protein processing, stress and hormone signaling, and carbohydrate metabolism. The turquoise module (15W) was dominated by carbon metabolism and flavonoid biosynthesis genes. Key flowering-related genes exhibited dynamic expression patterns: FT was specifically upregulated at the late stage (15W), AP2 genes peaked at mid-stage (9–12W), and COL9 showed early high expression (0–3W). Hormone-related gene analysis revealed extensive involvement of multiple pathways, with brassinosteroid (BR) signaling comprising the largest number of genes (101). Co-expression networks further identified hub genes, including FT, COL9, AP2, ERF1, SR160, LOX3-1, and transcription factor genes like MYB-related, as potential central regulators. Conclusions: Our findings demonstrate that blueberry leaves undergo a phased functional transition from a photosynthetic source to a hub for signal integration and metabolic support during floral bud morphogenesis, actively contributing to reproductive development through systemic signaling. This study provides novel insights into flowering regulation in woody perennials and establishes a foundation for marker-assisted breeding and cropping season management in blueberry. Full article

This study demonstrates that the ericoid mycorrhizal (ERM) fungus RM2 can colonize the non-ericaceous host Malus robusta as a functional endophyte, enhancing drought resilience through an active avoidance strategy. Under drought, inoculation was associated with qualitative changes in root growth patterns, and inoculated seedlings showed a more extensive and branched root appearance compared with non-inoculated controls. This morphological tendency was accompanied by a distinctive physiological state of oxidative priming, characterized by elevated H₂O₂ as a signaling molecule, reduced antioxidant enzyme activity, and a marked shift toward proline-mediated osmotic adjustment. Transcriptomic analysis suggested a molecular basis for these responses: endophytic colonization reprogrammed auxin and brassinosteroid signaling, including the repression of auxin inactivation (GH3) and activation of genes involved in auxin transport (AUX1) and cell wall loosening (TCH4), which is consistent with sustained root growth under drought. Our findings indicate that ERM fungi can transcend traditional host barriers and improve drought performance via integrated oxidative signaling and hormonal regulation, highlighting their potential as cultivable biostimulants for sustainable horticulture. Full article