Search Results (842)

Cytokinins are key regulators of plant root development, but their dose-dependent effects on rice seedling roots and their physiological association with ethylene-related responses remain incompletely understood. In this study, rice seedlings were exposed to two exogenous cytokinins, 6-benzyladenine (6-BA) and kinetin (KT), at different concentrations for 3 and 6 d, and Ag⁺ was used as an inhibitor of ethylene action to evaluate its alleviating effect. Both 6-BA and KT significantly inhibited primary root elongation in a concentration- and time-dependent manner. At high cytokinin concentrations, primary root length was reduced by more than 60% relative to the control, accompanied by reductions in total root length, lateral root number, absorptive area, and root vigor, as well as increased MDA and ethylene levels. Ag⁺ partially alleviated cytokinin-induced primary root inhibition, with the strongest rescue effect observed near 0.08 μM. The recovery effect was particularly evident under moderate and high cytokinin concentrations. Correlation and principal component analyses further indicated that root morphological traits were negatively associated with MDA and ethylene but positively associated with root vigor. These results suggest that exogenous cytokinins restrict rice seedling root growth through a coordinated physiological response associated with ethylene accumulation and increased membrane lipid peroxidation, while Ag⁺ partially relieves this inhibition in association with mitigation of ethylene-related restriction. Because the study was based on short-term exogenous treatments and pharmacological inhibition, the findings should be interpreted as physiological evidence for ethylene-related involvement rather than direct proof of a complete signaling mechanism. Full article

Plants must continuously balance the trade-offs between growth and defense, a constraint that is exacerbated by biotic and abiotic stresses, particularly when they occur together. Ethylene (ET) serves as a central, integrative regulatory node controlling this by linking developmental programs to stress-responsive signaling networks. Advances at the molecular and systems levels have revealed that ET mediates the redistribution of metabolic resources via coordinated regulation of its synthesis, perception, and downstream signaling. The ETR (Ethylene Receptor)-CTR1 (Constitutive Triple Response 1)-EIN2 (Ethylene Insensitive 2)-EIN3(Ethylene Insensitive 3) signaling module lies at the core of this network, integrating multiple hormonal pathways. Through dynamic crosstalk with jasmonic acid (JA), salicylic acid (SA), abscisic acid (ABA), auxin (AUX), and gibberellins (GA), ET enables the fine-tuned coordination of growth inhibition, immune activation, and stress acclimation in response to environmental fluctuations. Processes such as induced systemic resistance, programmed cell death, and architectural plasticity further reinforce this regulatory framework, with ethylene-responsive transcription factors, including ERFs (ethylene responsive factor gene family) and WRKYs, acting as critical convergence points. Emerging insights into ACC (1-aminocyclopropane-1-carboxylic acid) -dependent signaling, chromatin remodeling, and tissue-specific regulation expand the functional scope of ET beyond traditional hormone paradigms. At the same time, the ability of pathogens to manipulate ET signaling underscores its dual role in both promoting immunity and facilitating susceptibility. By integrating molecular, physiological, and ecological perspectives, this review highlights ET as a central coordinator of plant stress resilience and growth optimization, providing a unifying framework for understanding how plants adapt to complex and dynamic environments. Full article

Background: The NAC family constitutes one of the largest families of plant-specific transcription factors and plays crucial roles in fruit development, ripening, seed life, and stress responses. However, comprehensive characterization of NAC genes in Persea americana (avocado), an economically important horticultural crop, has been largely unexplored. Methods: We performed a genome-wide identification and systematic characterization of NAC transcription factor (TF) genes in P. americana using blastp analysis, phylogenetic reconstruction, expression profiling and weighted gene co-expression network analysis (WGCNA). Results: A total of 130 NAC genes (PaNACs) were identified and distributed across all 12 chromosomes. Phylogenetic analysis classified these PaNACs into eight distinct subfamilies. WGCNA identified 43 co-expression modules, with 68 PaNAC genes distributed across 24 modules associated with hormone signaling, cell wall modification, secondary metabolism, and fatty acid beta-oxidation. Among 48,785 developmental differentially expressed genes (DEGs), 70 PaNAC genes were differentially expressed, with PaNAC003 and PaNAC002 showing the strongest upregulation and PaNAC023 and PaNAC025 the strongest downregulation. Among 9488 ethylene-responsive DEGs, PaNAC041 was suppressed by ethylene and induced by 1-methylcyclopropene (1-MCP, a competitive inhibitor of ethylene perception), while PaNAC016, PaNAC085, and PaNAC086 showed the opposite pattern. Conclusions: These findings provide a genomic and transcriptional framework for future functional investigation of PaNAC genes and their potential relevance to avocado fruit development and postharvest ripening. Full article

JAZ (Jasmonate ZIM-Domain) proteins are key negative regulators of the jasmonic acid (JA) signaling pathway and are involved in various plant growth, development, and stress regulation. However, the functions of the JAZ gene family in Camellia nitidissima remain poorly understood. Here, ten CnJAZ genes were identified at the genome-wide level, encoding 134–398 amino acids and unevenly distributed across eight chromosomes. All CnJAZs were predicted to localize to the nucleus. Based on phylogenetic and structural analyses, the ten CnJAZs were classified into five subfamilies, with members of the same subfamily sharing similar exon–intron structures. Collinearity analysis with Arabidopsis thaliana and Malus domestica suggests that the JAZ gene family shares a common ancestor. Promoter analysis revealed cis-acting elements responsive to light, methyl jasmonate (MeJA), and anaerobic stress. Transcriptome profiling showed that most CnJAZs exhibit tissue- and development-specific expression, particularly during flower development and organ formation. RT-qPCR confirmed that MeJA and gibberellin (GA₃) significantly induced the expression of CnJAZ, whereas ethylene (ETH) treatment up-regulated CnJAZ3 and CnJAZ5 by 80-fold after three hours. These findings highlight their important roles in growth, development, and hormonal regulation in C. nitidissima, laying a foundation for functional studies. 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

Necrosis- and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are conserved microbial proteins that contain immunogenic patterns capable of activating plant pattern-triggered immunity (PTI). NLP patterns from Sclerotinia sclerotiorum (SsNLPs), a destructive necrotrophic fungal pathogen with a broad host range, have been identified, and their roles in PTI have been revealed. Nevertheless, the molecular mechanisms by which SsNLPs stimulate plant immunity remain largely unknown. In this study, we phylogenetically characterized SsNLPs and demonstrated the involvement of the phytocytokine receptor-like kinases PEPRs in SsNLP1-triggered immunity. SsNLPs contained the NPP1 domain and GHRHDWE motif and were phylogenetically closely associated with Botrytis cinerea NLPs. SsNLP1 treatment strongly induced the expression of PEPR genes. Further genetic analyses using Arabidopsis wild-type, pepr1 pepr2 double mutant, and PEPR1 overexpression lines showed that SsNLP1 elicited diverse immune responses, including reactive oxygen species (ROS) accumulation and defense gene activation, and induced plant resistance to S. sclerotiorum. Notably, the induced plant resistance and immune responses were strengthened in PEPR1 overexpression lines and significantly reduced in the pepr1 pepr2 mutant, indicating a positive role of PEPR signaling in SsNLP1-triggered immunity. Overall, our results revealed that phytocytokine PEPR1 signaling amplifies PAMP SsNLP1-triggered immunity, thereby enhancing resistance against S. sclerotiorum. Our findings provide an example of the coordination between PAMP- and phytocytokine-triggered immunity for robust resistance to a necrotrophic pathogen. 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

Seed germination is a critical determinant of seedling establishment, stress resistance, and final yield. ABA catabolism plays a central role in releasing seed dormancy and promoting germination, and ABA8ox is the key rate-limiting enzyme in this process. In this study, we used wild-type maize B73, and ZmABA8ox1b CRISPR-Cas9 knockout mutant as materials to investigate the biological function of ZmABA8ox1b. Compared with the wild type, the zmaba8ox1b mutant significantly delayed seed germination and enhanced the sensitivity to exogenous ABA. Endogenous ABA content in mutant embryos was drastically increased, indicating that ZmABA8ox1b is essential for ABA degradation during germination. The loss of ZmABA8ox1b function led to the activation of the ABA signaling pathway and severely impaired the responsiveness to exogenous ABA. Moreover, the mutation disturbed the expression and ABA responsiveness of auxin, gibberellin, ethylene, jasmonic acid, and brassinosteroid pathways, leading to a hormonal network imbalance. In conclusion, ZmABA8ox1b positively regulates maize seed germination by coordinating ABA catabolism and multi-hormone signal crosstalk. This study preliminarily clarifies the molecular mechanism of ZmABA8ox1b in germination control and provides important gene resources and theoretical support for breeding maize varieties. Full article

Gibberellins (GAs) are key endogenous hormones regulating chrysanthemum flowering, and Gibberellin INSENSITIVE DWARF1 (GID1) is the core receptor of the gibberellin (GA) signaling pathway. However, the functional mechanism of CmGID1A remains unelucidated. Here, we constructed CmGID1A-RNAi silencing lines and characterized the biological function of CmGID1A by phenotypic identification, protein interaction assays, qRT-PCR and RNA-seq. The results of RT-qPCR showed that CmGID1A responds to short days and gibberellins. Inhibition of the expression of CmGID1A can significantly promote the transition of chrysanthemum from the vegetative growth stage to the reproductive growth stage and accelerate its flowering process. Bimolecular fluorescence complementation (BiFC) and yeast two-hybrid (Y2H) assays confirmed that CmGID1A interacts with the DELLA protein CmRGL1 in a gibberellin-dependent manner. RNA-seq results revealed that silencing of CmGID1A leads to a significant up-regulation of downstream Ethylene Response Factor 6 (ERF6) expression. Collectively, CmGID1A acts as a GA receptor to mediate GA signal transduction via interacting with CmRGL1, and regulates the expression of CmERF6 and other downstream genes, thereby participating in the regulation of floral transition in chrysanthemum. This study clarifies the core role of CmGID1A in the GA signaling pathway and provides novel experimental data for enriching the molecular regulatory mechanism of GA in floral transition in chrysanthemum. Full article

Cannabis sativa L. is a predominantly dioecious species, but sex expression is highly plastic and can be modified by genetic, hormonal, developmental, and environmental factors. This plasticity has major implications for commercial production because hermaphroditic expression in female plants can cause unintended pollination, seed formation, reduced floral quality, and losses in cannabinoid yield. This review summarizes current understanding of sex determination and sex-expression instability in C. sativa, with emphasis on hermaphroditism and its agronomic significance. We examine the genomic architecture of sex determination, the roles of ethylene and gibberellin signaling, and the effects of exogenous chemical treatments used to alter sexual phenotype. Particular attention is given to silver-based ethylene inhibitors, especially silver thiosulfate, which remain the most effective tools for induced masculinization and feminized seed production. We also assess the role of environmental stressors in sex instability and review current approaches for early detection, including visual inspection, Raman spectroscopy, and sex-linked molecular markers. Overall, the available evidence supports a multilayered and context-dependent model in which genotype, treatment regime, developmental stage, and environmental conditions interact to shape sexual phenotype. Improved understanding of these processes will be essential for reducing hermaphroditic risk, improving breeding strategies, and supporting stable, high-value cannabis production. Full article

Lectin receptor-like kinases (LecRLKs) are a large subfamily of receptor-like kinases (RLKs), and their N-terminal lectin domain is predicted to reversibly bind to carbohydrates. Within this family, G-type LecRLKs represent a distinct subclass defined by an extracellular S-locus glycoprotein (SLG) domain, which was originally identified for its role in governing self-incompatibility in Brassica species. Emerging evidence suggests that G-type LecRLKs are involved in plant immunity; however, only a small fraction have been functionally characterized, leaving the roles of most family members largely unknown. In this study, we identified RK3 (Receptor Kinase 3) as the most strongly induced gene within the G-type LecRLK clade VI upon infection with Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Through both gain- and loss-of-function analyses, we demonstrated that RK3 positively regulates flg22-induced immune signaling events, including oxidative burst and mitogen-activated protein kinase (MAPK) activation, as well as downstream responses such as defense gene expression and ethylene production. Remarkably, the immune-enhancing activity of RK3 does not require its kinase domain. Critically, both full-length RK3 and a kinase-deleted variant (RK3-ΔK) constitutively interact with FLS2 (Flagellin-Sensing 2) and BAK1 (BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1). This provides direct evidence that RK3 functions primarily as a co-regulatory component within the PRR complex, independent of its kinase activity. Moreover, ectopic expression of RK3 in tomato enhanced resistance to Pst DC3000, highlighting its potential utility in engineering disease resistance in crops. Thus, RK3 reveals a non-canonical, kinase-independent mechanism by which a G-type LecRLK potentiates plant immunity, expanding our understanding of RLK signaling complexity. Full article

Fruit coloration is a key determinant of tomato quality, yet how light and temperature interact to regulate pigmentation during ripening remains unclear. Using a semi-in-fruit experimental system, we demonstrate that while high light accelerates chlorophyll degradation and lycopene accumulation at 25 °C, supra-optimal temperature (40 °C) completely abolishes lycopene biosynthesis irrespective of light conditions, primarily through transcriptional suppression of SlPSY1 and SlGGPS2. Elevated postharvest temperatures (≥30 °C) not only change the carotenoid composition but also reduce the antioxidant capacity and vitamin C content in fruit. Temperature-switch experiments revealed a critical developmental window, days 2–4 after ethylene treatment, during which temperature exerts dominant control over carotenoid metabolism. Exposure to high temperature within this window irreversibly shifts pigment accumulation from lycopene to yellow/orange carotenoids. These findings identify a temporally precise regulatory nexus integrating environmental signals with the ripening program, offering a framework for targeted temperature management to optimize tomato color and nutritional quality. Full article

Fusarium wilt caused by Fusarium oxysporum f. sp. cucumerinum Owen (FOC) is a major disease affecting cucumber production. Developing environmentally friendly prevention and control strategies is essential for managing cucumber Fusarium wilt (CFW). Bacillus velezensis is a beneficial microorganism with biocontrol potential against plant diseases. To investigate the biocontrol efficacy and induced disease resistance mechanism of B. velezensis FJ17-4 against CFW, the biocontrol effect of FJ17-4 on CFW was determined through indoor pot cultivation experiments, and the transcriptome of cucumber root samples treated with FJ17-4 was sequenced and analyzed by RNA-Seq technology. The results showed that CFW incidence was significantly reduced after FJ17-4 treatment, with 68.75% control efficacy, higher than that of Kasugamycin. A total of 1041 differentially expressed genes (DEGs) were induced, including 477 upregulated and 564 downregulated genes. DEGs associated with plant–pathogen interaction pathways (such as carbon metabolism, phenylpropanoid biosynthesis and amino acid biosynthesis), calcium (Ca²⁺) signaling pathway, and plant hormone signaling pathways [such as salicylic acid (SA), ethylene (ET), and jasmonic acid (JA)] were induced. These responses activated the disease resistance system of cucumber against CFW. Quantitative RT-PCR validation of 10 annotated DEGs confirmed consistent expression trends with the transcriptomic data. The results indicate that FJ17-4-induced disease resistance involves multiple genes and coordinated regulation of metabolisms, with hormone-mediated defense signaling pathways playing important roles. The transcriptome sequencing data provides a scientific basis for exploring the induced disease resistance mechanism of FJ17-4 and developing environmentally friendly biocontrol strategies. Full article

Fruit shape is determined by patterns of cell division and expansion during early development, yet the upstream transcription factors coordinating cell wall dynamics and cytoskeletal organization remain largely unknown. Here, we report that SlbHLH113, a bHLH transcription factor, positively regulates tomato fruit elongation. Overexpression (OE) of SlbHLH113 produced elongated fruits with increased length/width ratio, whereas RNAi lines exhibited flattened fruits. Histological analysis revealed that SlbHLH113 alters columella cell polarity—promoting elongated cell morphology without affecting cell area—and reduces columella–placenta width and locule width, without altering pericarp thickness. Transcriptomic profiling identified 87 differentially expressed genes in OE lines, with enrichment in cell wall-related processes. Notably, a pectate lyase gene (PL5) and an expansin gene (EXT90) were down-regulated, while genes involved in oriented cellulose deposition (COBRA4) and ethylene signaling were up-regulated. Importantly, SlbHLH113 physically interacts with the microtubule-associated protein SlIQD21a, as demonstrated by yeast two-hybrid and luciferase complementation assays. Finally, SlbHLH113 did not affect major nutrient contents in red-ripe fruits. Collectively, our findings identify SlbHLH113 as a novel regulator of tomato fruit shape that might act through cell polarity control, cell wall remodeling, and interaction with a microtubule-associated protein, offering a potential target for improving fruit morphology without compromising nutritional quality. Full article

Amino acids are organic compounds that serve as the fundamental building blocks of proteins and are additionally responsible for a multitude of other biological functions. This review synthesizes recent evidence elucidating that amino acids function as vital players in nitrogen transport, stress defense, and perhaps most intriguingly as signaling molecules. For example, glutamate triggers calcium signals through GLR receptors to guide root growth and pollen tubes. Others, like proline and glutathione, protect cells from drought, salt, and oxidative damage. Aromatic and sulfur-containing amino acids also feed into the production of hormones (auxin, ethylene) and a wide range of defense compounds. Beyond metabolism, we highlighted how plants sense amino acid status via ancient sensors such as PII and the TOR pathway, which fine-tune growth and resource allocation. Understanding this hidden side of amino acids opens new doors for agriculture. We discussed how these insights could lead to smarter biostimulants, gene-edited crops with better nutrient efficiency, and nano-based delivery systems. In short, amino acids are not just food for plants—they are signals, shields, and switches that shape how plants grow and cope with stress. Full article