Search Results (279)

Brassinosteroids (BRs) are essential regulators of plant development and stress responses, but the distinct contributions of BR biosynthesis and signaling to hormonal crosstalk remain poorly defined. Here, we investigated the effects of the BR biosynthesis inhibitor brassinazole (BRZ) and the BR-insensitive mutant bri1-6 on endogenous phytohormone profiles in Arabidopsis thaliana. Using multivariate analysis and targeted hormone quantification, we show that BRZ treatment and BRI1 disruption alter hormone balance through partially overlapping but mechanistically distinct pathways. Principal component analysis (PCA) and hierarchical clustering revealed that BRZ and the bri1-6 mutation do not phenocopy each other and that BRZ still alters hormone profiles even in the bri1-6 mutant, suggesting potential BRI1-independent effects. Both BRZ treatment and the bri1-6 mutation tend to influence cytokinins and auxin conjugates divergently. On the contrary, their effects on stress-related hormones converge: BRZ decreases salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) in the WT leaves; similarly, bri1-6 mutants show reduced SA, JA, and ABA. These results indicate that BR biosynthesis and BRI1-mediated perception may contribute independently to hormonal reprogramming, with BRZ eliciting additional effects, possibly via metabolic feedback, compensatory signaling, or off-target action. Hormone correlation analyses revealed conserved co-regulation clusters that reflect underlying regulatory modules. Altogether, our findings provide evidence for a partial uncoupling of BR levels and BR signaling and illustrate how BR pathways intersect with broader hormone networks to coordinate growth and stress responses. Full article

Irregular rooting in vitro is a major problem in the micropropagation of culinary rhubarb (Rheum rhaponticum), a vegetable crop rich in bioactive compounds. To date, little is known about the factors and mechanisms underlying adventitious root (AR) formation in rhubarb under in vitro conditions. Here, we studied the effects of indole-3-butyric acid (IBA) and its interaction with ethylene (ET) on AR development in rhubarb ‘Raspberry’ selection. To evaluate the ET-effect, we applied a precursor of ET biosynthesis—1 aminocyclopropane-1-carboxylic acid (ACC); an inhibitor of ET synthesis—aminoethoxyvinylglycine (AVG); and an inhibitor of ET action—silver nitrate (AgNO₃). The best results (96.9% rooting frequency, 12.7 roots/shoot) were obtained after adding ACC to the IBA-containing medium. The positive effect of ET was linked to decreased levels of cytokinin and auxins in the rhubarb shoot bases at the initiation and expression stages of rooting. Moreover, the enhanced expression levels of genes involved in auxin signalling and homeostasis (IAA17, GH3.1) and ABA catabolism (CYP707A1) were observed. The blocking of ethylene synthesis significantly increased JA production, and the rooting frequency decreased to 29.8%. The presence of AgNO₃ in the auxin medium resulted in a significant reduction in root number, which was consistent with the enhanced levels of ABA and the expression of genes related to ABA biosynthesis and signalling (PP2C49 and CBF4), as well as ET synthesis (ACO5). Full article

Indole-3-acetic acid (IAA), the predominant natural auxin, is a plant hormone that regulates growth and development in response to various internal and external signals. Arabidopsis thaliana (Arabidopsis) indole-3-butyric acid response 5 (AtIBR5, AT2G04550) encodes a dual-specificity phosphatase in Arabidopsis. The atibr5 mutant exhibits reduced sensitivity to indole-3-butyric acid (IBA), a precursor of IAA, but is also less responsive to another plant hormone, abscisic acid (ABA). We report that AtIBR5 contains a rubredoxin-like domain in its N-terminal region, in addition to the previously identified dual-specificity phosphatase domain. The rubredoxin-like domain of AtIBR5, when expressed in Escherichia coli, binds zinc through four cysteine residues in the rubredoxin-like domain and exhibits a characteristic absorption spectrum at 430 nm. The rubredoxin-like domain, more specifically the set of four cysteine residues, is essential for most in planta functions of AtIBR5 related to auxin and ABA. These functions include hypocotyl elongation, leaf serration, and germination phenotypes. However, this domain is dispensable for the inhibition of root elongation by ABA. All orthologs of AtIBR5 in the green plant lineage investigated encode the N-terminal rubredoxin-like domain, which features the specific arrangement of four cysteine residues. Our result provides a clue as to how various plant phenotypes can be subtly modulated by AtIBR5. Full article

This study explored the regulatory effects of exogenous glucose (Glu) and sucrose (Suc) on the growth performance and physiological mechanisms of cucumber seedlings under salt stress. Using two cucumber cultivars as experimental materials, pot experiments demonstrated that salt stress significantly suppressed seedling growth, decreased chlorophyll content, and triggered oxidative damage. However, pretreatment with exogenous sugars effectively mitigated these adverse effects by maintaining photosynthetic efficiency, enhancing the activities of key antioxidant enzymes—superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX)—and reducing the accumulation of reactive oxygen species (ROS) and membrane lipid peroxidation. Transcriptomic analysis revealed that the two sugars differentially modulated antioxidant pathways and transcription factor networks to synergistically enhance salt tolerance. Specifically, sucrose preferentially activated POD, whereas glucose specifically induced APX and RbohD. Furthermore, glucose upregulated NAC and ERF family genes, while sucrose suppressed certain WRKY members. Both sugars contributed to the restoration of auxin and abscisic acid (ABA) signaling pathways. This study provides a theoretical foundation for the role of sugar signaling in enhancing crop resistance to abiotic stress. Full article

We investigated the effect of Agrobacterium rhizogenes-mediated transformation mof rolB on adventitious root development and endogenous hormones in ‘duli’ (Pyrus betulaefolia) via transcriptomic analysis of wild-type (WT) and rolB-transformed plants. The formation of root primordia occurred earlier in transgenic ‘duli’ than in the WT plants. At seven days, 57% of the transgenic seedlings had formed root primordia, whereas root primordia first appeared at seven days in WT ‘duli’. The rooting rate of transgenic ‘duli’ and WT plants was 90% and 77.14%, respectively. rolB significantly promoted the formation of secondary roots. Within 20 days, auxin (IAA), gibberellic acid (GA₃), and zeatin riboside (ZR) were higher and abscisic acid (ABA) was lower in transgenic ‘duli’ than in WT plants. Gene Ontology analysis revealed high enrichment in signaling pathways and ADP binding, and Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that several differentially expressed genes were enriched in flavonoid and carotenoid-related pathways and plant hormone signal transduction. rolB induced changes in the expression patterns of several genes involved in hormone biosynthesis, metabolism, and signal transduction pathways in ‘duli’. Weighted gene co-expression network analysis identified the DEGs associated with endogenous hormone levels and indicated that the central genes of modules most strongly correlated with ABA, ZR, IAA, and GA₃ regulate protein synthesis, signaling, and root tissue meristem activity. Protein–protein interaction analysis yielded a co-expression network of physiological and transcriptomic data during rooting and identified key genes at the network core. These findings provide valuable insights into the regulatory mechanisms of rolB and its influence on root development in ‘duli’. Full article

Soybean seeds (Glycine max) are of great economic and nutritional importance due to their high oil and protein content. Seed germination is an essential process that influences crop yield and quality. The seed embryo resumes growth when it imbibes, which induces the expression of genes related to cell expansion. The role of acid growth in the embryonic axis during germination is not well characterized. Thus, the aim of this study was to verify the contribution of acid growth in the soybean embryonic axis germination. Acid growth is mediated by the acidification of extracellular medium due to the action of H+-ATPases, which activate expansins. We found that the expression of expansins was significantly increased throughout the germination. The expression of H+-ATPases was significantly increased at 3 and 24 h after imbibition (HAI), with major pumping activity at 24 HAI. The auxin and ABA signaling cascades during soybean germination suggest that these hormones are involved with the regulation of H+-ATPase in germinating soybean. To verify the influence of auxin and ABA on H+-ATPase functioning during germination, we treated seeds with IAA, 2,4D, ABA, and ATPase inhibitor, and germinated them in purple agar medium. We observed that IAA, 2,4D, and ABA affected H+-ATPase functioning, by delaying or inhibiting soybean germination. Our results indicate the role of acid growth controlled by H+-ATPase and its regulators—auxin and ABA—in the soybean embryonic axis during germination. Full article

Double-petal ornamental pomegranate presents for its enhanced ornamental value. Thus, cultivation techniques that promote petaloidy while modulating related gene expression are desired. To screen out the efficient treatments of plant growth regulator and key genes that enhance petaloidy, this study treated the flower buds of double- and single-petal ornamental pomegranate varieties with different concentrations of plant growth regulators naphthaleneacetic acid (NAA), methyl jasmonate (MeJA), abscisic acid (ABA), and ethephon (ETH) and quantified the number of petalized stamens (NOPSs) and the number of petals (NOPs) in both varieties. Furthermore, we investigated the expression levels of the genes flavin-containing monooxygenase (YUC), IAA-amino acid hydrolase (ILR1),indole-3-acetic acid-amido synthetase (GH3.17), auxin transporter (LAX2), auxin response factor (ARF), auxin-induced in root cultures protein (AIR12), jasmonic acid-amido synthetase (JAR1), and ABA stress ripening-induced protein (ASR) under the different treatments and analyzed their role in regulating relevant phenotypic traits. Plant growth regulator experiments demonstrated that NAA (10 mg/L) significantly increased the number of petalized stamens (NOPSs) and petals (NOPs), MeJA (100 mg/L) significantly increased the number of petalized stamens, while neither ABA nor ETH induced this morphological shift. qRT-PCR analysis confirmed that NAA upregulated ILR1, LAX2, ARF, and JAR1 in the stamens of single-petal flowers (StSi) and double-petal flowers (StDo) and petals of single-petal flowers (PeSi) and double-petal flowers (PeDo), with their expression levels strongly positively correlated with NOPS in both single- and double-petal flowers and NOP in double-petal flowers. MeJA upregulated ILR1, GH3.17, LAX2, ARF, and JAR1 in StDo and PeDo and was strongly positively correlated with NOPS and NOP in double-petal flowers. Consequently, NAA (10 mg/L) and MeJA (100 mg/L) were efficient treatments, and ILR1, GH3.17, LAX2, ARF, and JAR1 were identified as key genes in NAA- and MeJA-mediated petaloidy in ornamental pomegranates. Our results provide theoretical support for identifying the formation mechanism and improving industrial cultivation techniques for double-petal pomegranates. Full article

Ginger, an economically important crop, fulfills multifunctional roles as a spice, vegetable, and raw material for medicinal and chemical products. The family of Auxin Response Factors (ARFs) plays an essential role in facilitating auxin signal transduction and regulating plant growth and development. However, the role of ARF genes in ginger, a crop of considerable economic importance, remains elucidated. In this study, a total of 26 ZoARF genes were identified in the ginger genome, which were further categorized into four subfamilies (I–IV) and displayed a non-uniform distribution across 11 chromosomes. The proteins are predominantly localized to the nucleus. Promoter regions contained numerous cis-elements linked to light signaling, phytohormones, growth, development, and stress responses. Collinearity analysis revealed 9 pairs of fragment duplication events in ZoARFs, all uniformly distributed across their related chromosomes. In addition, the expression profiles of ZoARFs in ginger were analyzed during development and under several stress conditions like ABA, cold, drought, heat, and salt, employing RNA-seq data and qRT-PCR analysis. Notably, expression profiling revealed tissue-specific functions, with ZoARF#04/05/12/22 associated with flower development and ZoARF#06/13/14/23 implicated in root growth. This work provides an in-depth insight into the ARF family and establishes a foundation for future investigations of ZoARF gene functions in ginger growth, development, and abiotic stress tolerance. 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

Rhododendron spp., valuable ornamental plants, frequently suffer from infestations of the azalea lace bug (Stephanitis pyrioides Scott, ALB). However, the hormonal regulatory mechanisms underlying Rhododendron defense against ALB are not well understood. In this study, integrated transcriptomic and metabolomic analyses were performed to investigate the phytohormone responses under ALB stress in two Rhododendron cultivars with distinct insect susceptibility: the resistant ‘Taile’ (TL), and the susceptible ‘Yanzhimi’ (YZM). Transcriptomic sequencing identified 10,052 and 3113 differentially expressed genes (DEGs) in ‘TL’ and ‘YZM’, respectively, after ALB infestation. KEGG pathway enrichment analysis revealed that the DEGs in ‘TL’ were significantly enriched in hormone signal transduction pathways, including gibberellin (GA), jasmonic acid (JA), salicylic acid (SA), and ethylene (ETH), with 21 out of 25 hormone-related DEGs being upregulated. In contrast, ‘YZM’ exhibited 18 upregulated and 13 downregulated DEGs and suppressed auxin and cytokinin signaling. Non-targeted metabolomic analysis detected increased indole-3-acetic acid (IAA), abscisic acid (ABA), and jasmonoyl–isoleucine (JA-Ile) levels in both cultivars. ‘TL’ also showed elevated levels of SA precursor (benzoic acid) and ethylene precursor (1-aminocyclopropane-1-carboxylate, ACC). These findings indicate that ALB infestation induces endogenous hormone signaling-related genes in Rhododendron leaves and regulates hormones such as SA and JA to counteract insect stress. This study provides theoretical insights into the molecular mechanisms of Rhododendron defense against insect herbivory and lays the foundation for breeding resistant cultivars. Full article

The AP2/ERF (APETALA2/ethylene-responsive element binding factor) family represents one of the largest transcription factor families in plants, playing pivotal roles in abiotic stress responses and hormone signaling pathways. Through genome-wide analysis, we identified 163 AnAP2/ERF genes in Adiantum nelumboides. Transcriptome data revealed that 12 AnAP2/ERF genes were significantly upregulated under either drought or flooding stress, with 8 genes responding to both conditions. qRT-PCR validation confirmed that all 12 selected AnAP2/ERF genes exhibited differential expression under both stress types. Notably, these genes also showed significant induction by abscisic acid (ABA), auxin (IAA), and gibberellin (GA), suggesting their potential involvement in stress responses through hormone crosstalk. This study establishes a foundation for investigating AnAP2/ERF gene functions and their molecular mechanisms in abiotic stress adaptation in A. nelumboides. Full article

Xyloglucan endotransglucosylase/hydrolases (XTHs) are a class of cell wall-associated enzymes involved in the construction and remodeling of cellulose/xyloglucan crosslinks. However, knowledge of this gene family in the model monocot Brachypodium distachyon is limited. A total of 29 BdXTH genes were identified from the whole genome, and these were further divided into three subgroups (Group I/II, Group III, and the Ancestral Group) through evolutionary analysis. Gene structure and protein motif analyses indicate that closely clustered BdXTH genes are relatively conserved within each group. A highly conserved amino acid domain (DEIDFEFLG) responsible for catalytic activity was identified in all BdXTH proteins. We detected three pairs of segmentally duplicated BdXTH genes and five groups of tandemly duplicated BdXTH genes, which played vital roles in the expansion of the BdXTH gene family. Cis-elements related to hormones, growth, and abiotic stress responses were identified in the promoters of each BdXTH gene, and when roots were treated with two abiotic stresses (salinity and drought) and four plant hormones (IAA, auxin; GA3, gibberellin; ABA, abscisic acid; and BR, brassinolide), the expression levels of many BdXTH genes changed significantly. Transcriptional analyses of the BdXTH genes in 38 tissue samples from the publicly available RNA-seq data indicated that most BdXTH genes have distinct expression patterns in different tissues and at different growth stages. Overexpressing the BdXTH27 gene in Brachypodium led to reduced root length in transgenic plants, which exhibited higher cellulose levels but lower hemicellulose levels compared to wild-type plants. Our results provide valuable information for further elucidation of the biological functions of BdXTH genes in the model grass B. distachyon. Full article

Cinnamomum camphora is an ecologically and economically significant species, highly valued for its essential oil production and environmental benefits. Although a tissue culture system has been established for C. camphora, large-scale propagation remains limited due to the inconsistent formation of adventitious roots (ARs). This study investigated AR formation from callus tissue, focusing on associated physiological changes and gene expression dynamics. During AR induction, contents of soluble sugars and proteins decreased, alongside reduced activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and polyphenol oxidase (PPO). Levels of indole-3-acetic acid (IAA) and abscisic acid (ABA) decreased significantly throughout AR formation. Zeatin riboside (ZR) levels initially declined and then rose, whereas gibberellic acid (GA) levels displayed the opposite trend. Comparative transcriptomic and temporal expression analyses identified differentially expressed genes (DEGs), which were grouped into four distinct expression patterns. KEGG pathway enrichment indicated that 67 DEGs are involved in plant hormone signaling pathways and that 38 DEGs are involved in the starch and sucrose metabolism pathway. Additionally, protein–protein interaction network (PPI) analysis revealed ten key regulatory genes, which are mainly involved in auxin, cytokinin, GA, ABA, and ethylene signaling pathways. The reliability of the transcriptome data was further validated by quantitative real-time PCR. Overall, this study provides new insights into the physiological and molecular mechanisms underlying AR formation in C. camphora and offers valuable guidance for optimizing tissue culture systems. Full article

The worldwide agriculture industry is facing increasing problems due to rapid population increase and increasingly unfavorable weather patterns. In order to reach the projected food production targets, which are essential for guaranteeing global food security, innovative and sustainable agricultural methods must be adopted. Conventional approaches, including traditional breeding procedures, often cannot handle the complex and simultaneous effects of biotic pressures such as pest infestations, disease attacks, and nutritional imbalances, as well as abiotic stresses including heat, salt, drought, and heavy metal toxicity. Applying phytohormonal approaches, particularly those involving hormonal crosstalk, presents a viable way to increase crop resilience in this context. Abscisic acid (ABA), gibberellins (GAs), auxin, cytokinins, salicylic acid (SA), jasmonic acid (JA), ethylene, and GA are among the plant hormones that control plant stress responses. In order to precisely respond to a range of environmental stimuli, these hormones allow plants to control gene expression, signal transduction, and physiological adaptation through intricate networks of antagonistic and constructive interactions. This review focuses on how the principal hormonal signaling pathways (in particular, ABA-ET, ABA-JA, JA-SA, and ABA-auxin) intricately interact and how they affect the plant stress response. For example, ABA-driven drought tolerance controls immunological responses and stomatal behavior through antagonistic interactions with ET and SA, while using SnRK2 kinases to activate genes that react to stress. Similarly, the transcription factor MYC2 is an essential node in ABA–JA crosstalk and mediates the integration of defense and drought signals. Plants’ complex hormonal crosstalk networks are an example of a precisely calibrated regulatory system that strikes a balance between growth and abiotic stress adaptation. ABA, JA, SA, ethylene, auxin, cytokinin, GA, and BR are examples of central nodes that interact dynamically and context-specifically to modify signal transduction, rewire gene expression, and change physiological outcomes. To engineer stress-resilient crops in the face of shifting environmental challenges, a systems-level view of these pathways is provided by a combination of enrichment analyses and STRING-based interaction mapping. These hormonal interactions are directly related to the United Nations Sustainable Development Goals (SDGs), particularly SDGs 2 (Zero Hunger), 12 (Responsible Consumption and Production), and 13 (Climate Action). This review emphasizes the potential of biotechnologies to use hormone signaling to improve agricultural performance and sustainability by uncovering the molecular foundations of hormonal crosstalk. Increasing our understanding of these pathways presents a strategic opportunity to increase crop resilience, reduce environmental degradation, and secure food systems in the face of increasing climate unpredictability. Full article

Anthocyanins are important phenolic compounds in grape skins, affecting the color, oxidation resistance, and aging ability of red wine. In recent years, global warming has had a negative effect on anthocyanin biosynthesis in grape berries. Ethylene serves as a crucial phytohormone regulating the development and ripening processes of fruit; however, the specific molecular mechanism and the regulatory network between ethylene signaling and the anthocyanin biosynthesis pathway remain incompletely understood. In this study, 400 mg/L ethephon (ETH) solution was sprayed onto the surface of grape berries at the lag phase (EL-34), and the changes in anthocyanin-related genes and metabolites were explored through transcriptomic and metabolomic analysis. The results showed that ETH treatment increased Brix and pH in mature berries. In total, 35 individual anthocyanins were detected, in which 21 individual anthocyanins were enhanced by ETH treatment. However, the anthocyanin profile was not affected by exogenous ethylene. Transcriptomics analysis showed that there were a total of 825 and 1399 differentially expressed genes (DEGs) 12 h and 24 h after treatment. Moreover, key structural genes in the anthocyanin synthesis pathway were strongly induced, including VvPAL, VvCHS, VvF3H, VvF3′5′H, VvDFR and VvUFGT. At the maturity stage (EL-38), the expression levels of these genes were still higher in EHT-treated berries than in the control. ETH treatment also influenced the expression of genes related to hormone biosynthesis and signal transduction. The ethylene biosynthesis gene (VvACO), ethylene receptor genes (VvETR2, VvERS1 and VvEIN4), ABA biosynthesis gene (VvNCED2), and ABA receptor gene (VvPYL4) were up-regulated by ETH treatment, while the auxin biosynthesis gene (VvTAA3) and seven genes of the auxin-responsive protein were inhibited by exogenous ethylene. Meanwhile, ETH treatment promoted the expression of the sugar transporter gene (VvEDL16) and two sucrose synthase genes (VvSUS2 and VvSUS6). In EHT-treated berries, 19 MYB and 23 ERF genes were expressed differently compared with the control (p < 0.05). This study provides the theoretical foundation and technical support for the regulation of anthocyanin synthesis in non-climacteric fruit. Full article