Search Results (695)

To overcome the seasonal constraints of explant availability and facilitate genetic improvement in Catalpa ovata, this study established a dual-pathway in vitro regeneration system (encompassing adventitious shoot organogenesis and somatic embryogenesis) using mature zygotic embryos. We systematically evaluated the synergistic effects of maternal genotypes, plant growth regulators (PGRs), basal media, and the histone deacetylase inhibitor Trichostatin A (TSA). Genotype screening revealed significant divergence in regenerative potential, with the half-sib family 32F17 exhibiting superior responsiveness (84.7% callus induction). A high cytokinin-to-auxin ratio (ZA3 medium) optimally drove direct shoot organogenesis. For adventitious shoot proliferation, the addition of TDZ significantly improved the multiplication coefficient (up to 2.99 on ZB4 medium), although a physiological trade-off with shoot elongation was observed. In parallel, the application of 10 µM TSA significantly enhanced somatic embryogenesis from embryogenic calli, effectively alleviating the inhibitory constraints of exogenous PGRs. For rhizogenesis, the DKW basal medium proved superior to half-strength MS, with the ZE3 treatment (0.1 mg·L⁻¹ NAA + 0.1 mg·L⁻¹ IBA) yielding the highest rooting frequency (69.6%) and robust root architecture. Notably, while somatic embryo conversion remained recalcitrant, plantlets derived exclusively from the adventitious shoot organogenesis pathway were successfully acclimatized ex vitro. These transplanted plantlets exhibited consistently high survival rates (83.1–84.4%) across all tested genotypes, effectively overcoming the initial genotype-dependent recalcitrance. Collectively, this optimized protocol provides a reliable technical platform for the large-scale clonal propagation and biotechnological breeding of C. ovata. Full article

Corolla movement is a typical plant movement behavior that enables plants to optimize pollination and adapt to environmental changes. Nevertheless, its molecular mechanism remains poorly understood. In the present study, we conduct a comprehensive transcriptome analysis of Mirabilis jalapa (Nyctaginaceae) corolla at five stages (AG-EG) to elucidate the regulatory networks underlying movement. The results showed that the differentially expressed genes (DEGs) were mainly associated with cellular processes, catalytic activity, MAPK signaling, plant hormone signal transduction, and photosynthesis-related pathways, highlighting their involvement in corolla dynamics. Transcriptome profiling further demonstrated that auxin, ethylene, and abscisic acid signaling pathways were key hormonal regulators of corolla movement. Moreover, Ca²⁺ transport genes (CNGCs and CMLs) and respiratory burst oxidase homologs (RBOHs) were significantly enriched, indicating that Ca²⁺–ROS signaling oscillations also play an important role in driving differential cell expansion and turgor changes. Transcription factor analysis also revealed the upregulation of WRKY2, WRKY22, and WRKY33, suggesting that WRKYs act as the critical transcriptional regulators linking ROS–Ca²⁺ signals with downstream gene expression. The reliability of RNA-Seq data was confirmed by RT-qPCR, which showed high consistency with transcriptome profiles. These findings suggested that corolla movement in M. jalapa is carried through the integration of hormonal pathways, Ca²⁺–ROS signaling, and WRKY-mediated transcriptional regulation. This research provided novel insights into the molecular basis of plant movement and established a foundation for further study on floral dynamics and adaptive strategies in angiosperms. Full article

Cadmium (Cd) is widely dispersed in the environment and has emerged as a major environmental contaminant. Although Salix viminalis shows potential for phytoremediation of Cd pollution, the defence mechanism of its roots against heavy metals remains unclear. This study explores the adaptive response of S. viminalis roots to Cd stress from physiological, transcriptomic, and metabolomic perspectives. The results suggest that Cd stress exerts inhibitory effects on root growth and development. Compared with the control (Cd-free), the root volume and dry weight of S. viminalis exposed to Cd decreased by 26% and 29%, respectively. After exposure to Cd stress for 14 and 21 days, the Cd content in the roots increased by 117-fold and 134-fold, the hydrogen peroxide content increased by 89% and 110%, and the malondialdehyde content increased by 82% and 88%, respectively. This phenomenon can be attributed to the fact that the continuous accumulation of Cd in the roots may have aggravated the degree of lipid peroxidation. A total of 9171 differentially expressed genes (DEGs) and 169 differential metabolites (DIMs) were identified through transcriptomic and metabolomic analyses. Further combined analyses revealed the potential roles of several pathways in the defensive response of S. viminalis roots against Cd stress, including plant hormone signal transduction, thiamine metabolism, glycolysis, glycerophospholipid metabolism, and other pathways. Notably, the feedback regulatory effects formed by thiamine metabolism and hormone signal transduction related to auxin, jasmonic acid, and salicylic acid play a crucial role in the early stage when roots are exposed to Cd stress. These effects mobilized osmotic adjustment in roots by enhancing saccharide metabolism and activated the Cd detoxification process by altering lipid metabolism, thereby contributing positively to the defence of willow roots against Cd stress. These findings provide insights into the adaptive mechanism of S. viminalis roots in response to Cd and the application of fast-growing woody plants in heavy metal phytoremediation. Full article

Hevea brasiliensis (H. brasiliensis) is the principal source of natural rubber, but its productivity is severely threatened by powdery mildew caused by the biotrophic fungus Erysiphe quercicola (E. quercicola). Although circular RNAs (circRNAs) are emerging as key regulators in plant stress responses, their functions in H. brasiliensis immunity remain largely unexplored. Here, we aimed to systematically characterize circRNAs involved in the early immune response of H. brasiliensis to E. quercicola. Transcriptome sequencing and bioinformatic analyses identified 52 and 177 differentially expressed circRNAs (HbcircRNAs) at 1 and 3 days post-inoculation, respectively. Twelve HbcircRNAs with significant expression changes were validated, and nine were confirmed as true circRNAs. Functional assays using spray-induced gene silencing (SIGS) in H. brasiliensis leaves and heterologous overexpression in the Arabidopsis thaliana eds1 mutant, which is susceptible to E. quercicola, revealed that HbcircARF3, HbcircSCSA1, and HbcircARFGAP8, together with their homologous linear counterparts (HbLinearRNAs), exert distinct regulatory effects on disease resistance. Silencing of these HbcircRNAs enhanced host immunity, whereas overexpression increased susceptibility. Pathway analyses suggested their involvement in auxin signaling, mitochondrial energy metabolism and vesicle trafficking. Collectively, our findings uncover the differential regulatory roles of circular and linear RNAs in the H. brasiliensis–E. quercicola interaction, providing mechanistic insights and potential molecular targets for breeding disease-resistant H. brasiliensis. Full article

Background: Protein phosphatase 2Cs (PP2Cs) constitutes the largest phosphatase family in plants, playing a pivotal role in signal transduction. Within this family, the PP2C.D subfamily exerts significant influence on cell elongation and stress adaptation by mediating the ‘SAUR-PP2C.D-H+-ATPase’ regulatory module in the auxin signaling pathway. In rice, OsPP2C61 is a PP2C member whose molecular features and potential regulatory context remain unclear. Methods: Our study conducted a preliminary characterization of OsPP2C61 through integrated bioinformatics analysis, spatiotemporal expression profiling, and subcellular localization experiments in tobacco leaf cell. Results: OsPP2C61 encodes a 377-amino-acid protein predicted to be hydrophilic, basic, and structurally unstable. Secondary-structure prediction identified three major elements with random coils as the predominant component, whereas 3D modeling indicated alternating α-helices and β-sheets consistent with a canonical PP2C fold. Phylogenetic inference placed OsPP2C61 within the PP2C.D clade and revealed conserved motifs shared with OsPP2C25, OsPP2C28, and OsPP2C39. Promoter analysis showed enrichment of abscisic acid (ABA)- and methyl jasmonate (MeJA)-responsive elements along with multiple stress-related cis-regulatory motifs. Spatiotemporal expression analysis showed that OsPP2C61 is highly expressed in roots. Subcellular localization assays further demonstrated that the OsPP2C61-GFP fusion protein localizes to the nucleus and the plasma membrane when transiently expressed in epidermal cells of Nicotiana benthamiana. Conclusions: This work delivers the first comprehensive characterization of OsPP2C61, establishing a foundation for mechanistic studies and positioning OsPP2C61 as a candidate gene for rice improvement. Full article

The application of dual cytokinins can significantly enhance shoot multiplication rates in specific apple cultivars compared to standard protocols using a single cytokinin. This study presents a comprehensive analysis of shoot multiplication parameters and the underlying transcriptomic response of two distinct apple scion cultivars, cvs. Húsvéti rozmaring and McIntosh, to the simultaneous application of two cytokinins (BA and KIN). Morphological parameters were recorded, followed by comparative RNA-seq analysis and RT-qPCR validation. Our results demonstrate that the BA+KIN treatment induces a unique transcriptomic signature in both cultivars, which cannot be explained by a simple dose–response effect. In cv. McIntosh, 76% of the DEGs were uniquely regulated by the combination, while in cv. Húsvéti rozmaring, although the overlap with single treatments was higher, 17% of the DEGs (representing 1218 genes) were still exclusively activated by the BA+KIN treatment. The fact that the combined treatment recruits specific gene sets and metabolic pathways that remain silent under single BA or KIN applications—regardless of the cultivar—strongly supports a synergistic or non-additive hormonal interaction rather than a response to increased total cytokinin concentration. The dual treatment revealed 3209 DEGs in the inter-cultivar comparison, reflecting distinct strategies: cv. Húsvéti rozmaring achieved high efficiency growth by down-regulating internal hormones, whereas cv. McIntosh exploited intense auxin signaling and hormonal plasticity to maximize bud release. These results prove that distinct molecular pathways can lead to peak performance depending on the apple cultivar. Full article

Walnut (Juglans regia) is an economically significant woody oil tree species widely cultivated in China. However, its production is increasingly threatened by extreme low-temperature events, such as unseasonal frosts and late-spring cold. Salicylic acid (SA) is a key phytohormone known to enhance cold tolerance in plants, yet its underlying mechanism in walnut remains unclear. In this study, we present the first integrated analysis combining physiological measurements, transcriptomics, and metabolomics to investigate how exogenous SA improves cold tolerance in walnut leaves. Our results showed that SA treatment significantly increased the accumulation of soluble sugars, chlorophyll, and proline, enhanced peroxidase (POD) activity, and reduced malondialdehyde (MDA) levels under cold stress. Multi-omics analysis revealed that SA modulated the expression of genes involved in multiple hormone signaling pathways, including those of SA, auxin, jasmonic acid, and abscisic acid, and altered corresponding hormone levels. Notably, carbohydrate metabolism emerged as a central pathway mediating SA-induced cold adaptation. Weighted gene co-expression network analysis (WGCNA) further identified several core candidate genes, such as JrTGA, JrPP2C, JrTPS, and JrBAM, which may play key roles in this process. Collectively, this study provides the first multi-omics perspective on the regulatory network underlying SA-enhanced cold tolerance in walnut. These findings offer both a theoretical and technical foundation for applying SA in cold-resistant walnut cultivation and contribute to the development of stress-resilient production strategies. Full article

Plant growth regulation is orchestrated by complex hormonal networks involving gibberellin and auxin signaling pathways. In this study, a comprehensive in silico approach was employed to comparatively evaluate the plant growth regulators (PGRs) forchlorfenuron (CPPU) and strigol (STG) against two key proteins from Arabidopsis thaliana: Gibberellin 3-beta-dioxygenase 2 (GA3Ox2), a rate-limiting enzyme in the biosynthesis of bioactive gibberellins, and the auxin signaling repressor IAA7. These targets were specifically selected because they represent critical regulatory nodes in two major hormonal pathways controlling plant growth: GA3Ox2 governs the final steps of gibberellin activation, while IAA7 modulates auxin-responsive gene expression through its interaction with Auxin Response Factors. Therefore, their combined analysis enables the evaluation of potential regulatory effects of PGRs on both gibberellin biosynthesis and auxin-mediated transcriptional control. Molecular docking analyses revealed that both ligands exhibited higher binding affinity toward GA3Ox2 than IAA7, with STG showing slightly more favorable binding energies (−7.91 kcal/mol for GA3Ox2 and −5.43 kcal/mol for IAA7) compared to CPPU (−7.18 and −4.79 kcal/mol, respectively). These results suggest a structural preference of both PGRs toward the gibberellin biosynthetic pathway. To further assess complex stability under near-physiological conditions, 100 ns molecular dynamics (MD) simulations were conducted using the CHARMM36m force field. Despite its slightly lower docking scores, CPPU demonstrated greater conformational stability, lower RMSD fluctuations, and more persistent hydrogen bonding patterns, particularly in complexes with IAA7. In contrast, STG induced more pronounced conformational rearrangements, although it promoted slightly more compact protein conformations in certain systems. Fourier-transform infrared (FTIR) spectroscopy supported the computational findings by confirming the presence of key functional groups responsible for hydrogen bonding and hydrophobic interactions. Collectively, the results indicate that although STG exhibits higher initial binding affinity, CPPU forms more dynamically stable complexes with both proteins. These findings suggest that CPPU may represent a more robust candidate for sustained modulation of auxin and gibberellin signaling pathways in plant growth regulation. Full article

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

Osmanthus fragrans, a fragrant plant native to China, is extensively utilized in the food and cosmetics industries. However, its optimal harvest period spans only 2–3 days, restricting industrial utilization. Long non-coding RNAs (lncRNAs) have emerged as key regulators of plant growth, yet their roles in O. fragrans petal opening and senescence remain unexplored. Here, we performed high-throughput sequencing of O. fragrans petals across six developmental stages, generating a valuable transcriptomic resource. We identified 57,860 mRNAs and 2414 lncRNAs, including 6499 differentially expressed mRNAs (DEMs) and 494 differentially expressed lncRNAs (DELs). Co-expression and WGCNA analyses revealed key modules associated with petal opening (Turquoise module) and senescence (Blue module). The Blue module, significantly correlated with the S6 senescence stage, contained hub lncRNAs novel_00098659 and novel_00077227 co-expressed with multiple transcription factors and hormone signaling components, including 10 ERFs, OfEIN3, OfJAZ, and OfMYC2. Transient overexpression of novel_00077227 in tobacco accelerated leaf senescence in a hormone-dependent manner, with significant increases in electrolyte leakage and MDA content, and reductions in chlorophyll content and antioxidant enzyme activities. qRT-PCR analysis confirmed that novel_00077227 alters the expression of tobacco homologs of predicted target genes involved in ethylene, auxin, jasmonate, and ABA signaling pathways. This study provides a valuable transcriptomic resource of senescence-associated lncRNAs in O. fragrans and offers evidence for the potential involvement of a key candidate, novel_00077227, in hormone-associated senescence regulation. These findings provide a foundation for future functional studies and potential applications in extending flower longevity. Full article

Armillaria solidipes, the causal agent of Armillaria root rot, poses a severe and persistent threat to poplar forest plantations. This study evaluated the biocontrol efficacy of the endophytic bacterium Bacillus velezensis BY6 against this pathogen and elucidated its multimodal mechanisms of action. BY6 application significantly reduced disease severity by 37.19% at 30 days post-treatment. 16S rRNA (V3–V4) microbiome analysis revealed that BY6 reshaped both the rhizosphere and phyllosphere bacterial communities, consistently enriching beneficial taxa, including Pantoea ananatis and members of Acidobacteria, while suppressing opportunistic groups. Concurrently, BY6 activated systemic defenses in poplar, evidenced by enhanced activities of key enzymes PAL and POD, and the upregulated expression of SA/JA pathway marker genes (PR1, JAZ, and COI1), coupled with the downregulation of the auxin transporter gene AUX1. These data indicate that the biocontrol efficacy of B. velezensis BY6 was mediated by a dual mechanism: the modulation of both rhizospheric and phyllospheric bacterial communities, direct elicitation of systemic defense pathways in poplar, which synergistically enhanced resistance against A. solidipes. Full article

To decipher the molecular response mechanism of melon to saline–alkaline stress, seedlings of the melon cultivar “Xikaixin” were treated with 50 mmol·L⁻¹ mixed solutions of NaCl and NaHCO₃ at ratios of 1:1, 1:2, and 2:1 to simulate saline–alkaline stress. Transcriptome sequencing of roots (four biological replicates per group, with each replicate consisting of one pot containing four robust seedlings as the experimental unit) yielded 78.98 Gb of clean data (≥6.02 Gb per sample) with Q30 ≥ 96.61% and genome alignment rates of 97.00–98.02%, identifying 588, 686, and 1107 differentially expressed genes (DEGs) in the 1:1, 1:2, and 2:1 groups, respectively. Notably, the 1:1 treatment—mimicking the natural NaCl:NaHCO₃ ratio of saline–alkaline soil in southern Xinjiang—had 588 DEGs with the plant hormone signal transduction pathway as its most significantly enriched pathway, representing the core molecular response of “Xikaixin” to near-natural saline–alkaline stress. DEGs were significantly enriched in 50 pathways categorized into five major classes, with the plant hormone signal transduction pathway showing the highest enrichment across all treatments. A key observation from gene expression patterns is a potential auxin–ABA balance modulation, inferred from the differential expression of annotation-based auxin-related and ABA-related genes/pathways (no direct measurement of hormone levels or signaling was performed): two auxin-related genes (auxin-induced protein gene MELO3C013403 and auxin response factor gene MELO3C004381) were specifically upregulated (≥two fold vs. control) in the high-salt 2:1 group, while ABA-related genes were upregulated and auxin/jasmonic acid/gibberellin-related genes were downregulated in the 1:2 group, indicating a putative cultivar-specific hormone-related gene expression pattern associated with auxin–ABA crosstalk in “Xikaixin” under saline–alkaline stress. In contrast, photosynthesis-antenna protein genes (e.g., MELO3C021567) were significantly downregulated (to 32% of the control) under the 2:1 treatment. RT-qPCR validation confirmed the consistency of these candidate genes’ expression with transcriptomic data. Therefore, melon may respond to saline–alkaline stress by regulating the plant hormone signal transduction (especially auxin–ABA balance), photosynthesis, and carbon metabolism pathways. This study provides novel candidate genes and a theoretical basis for the genetic improvement of saline–alkaline-tolerant melon cultivars, with the unique auxin–ABA balance modulation as a key original contribution. Full article

Background/Objectives: Nitrogen, as an indispensable macroelement for plants, is essential for tuber development. The objective of the present study was to ascertain the key factors underlying nitrogen regulation of potato tuber formation. Methods: The potato variety Kexin 37 was used as the material, and nitrogen deficiency, normal nitrogen level and excessive nitrogen level were employed as treatments, respectively. The response of potato tuber formation to nitrogen was systematically analyzed from the perspective of physiology and transcriptomics. Results: Nitrogen deficiency led to the thickening of the cell wall and plasma membrane, an increase in intercellular space and a decrease in mitochondria in the stolon. The plant height, chlorophyll content, dry matter quality and nitrogen accumulation were significantly reduced, and the number of tubers per plant, tuber weight per plant and commodity rate were significantly reduced. Excessive nitrogen application resulted in late maturity of plants and excessive formation of small potatoes. Transcriptome analysis revealed that differentially expressed genes related to nitrogen stress were mainly enriched in pathways associated with material transport, cell division and carbohydrate metabolism. In addition, there are a series of hub genes in response to nitrogen stress, including polyubiquitin-like, auxin response factor 7-like and protein RRP6-like 2. By constructing a co-expression network, transcription factors (TFs) such as C2H2, WRKY and ARF are involved in regulating tuber formation. Conclusions: The present study constitutes an investigation into the identification of hub genes and potential pathways associated with the formation of potato tubers under varying nitrogen conditions. It provides new insights for further study on enhancing nitrogen use efficiency in potato. Full article

Mature-green tomatoes are prone to rapid ripening and quality deterioration during the postharvest stage, highlighting the urgent need for environmentally friendly and efficient preservation technologies. This study investigated the synergistic regulatory effects of nano-SiO₂ and light quality (white light, W; blue light, B; red/blue mixed light, RB, 1:1) on postharvest appearance, physiological processes, and quality attributes in ‘Yu Zhu’ (Solanum lycopersicum L.), a tasty tomato cultivar with light-yellow fruit color. Mature-green fruits were treated with light quality in combination with nano-SiO₂ (pre-immersion in 1 mL/L nano-SiO₂ for 1 h, followed by periodic spraying with 0.5 mL/L nano-SiO₂ every two days). Key indicators—including ripening traits, flavor attributes, antioxidant capacity, and endogenous hormone metabolites—were monitored on their respective sampling days. The results revealed distinct light quality-dependent responses: (1) B-Si (B + nano-SiO₂) significantly delayed the breaker stage compared to W, maintained the lowest water loss, and exhibited the slowest softening rate. W-Si showed a significantly higher dry weight-to-fresh weight ratio than W. (2) RB-Si achieved superior flavor quality, with 11.47% soluble solids, 1.62% titratable acidity, and a sugar-to-acid ratio of 7.2—values markedly higher than those in RB. (3) RB-Si increased total phenolic (TP), flavonoids, and ascorbic acid (AsA) levels relative to RB, while enhancing total antioxidant capacity (T-AOC) and the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), with only slight suppression of ascorbate peroxidase (APX) activity. (4) Nano-SiO₂ differentially regulated hormonal metabolism depending on light quality: it activated the jasmonic acid (JA)–gibberellin (GA) pathway under W light, fine-tuned cytokinin (CK) metabolism under B light, and upregulated JA, GA, CK, and auxin under RB light. Moreover, RB-Si significantly reduced ACC accumulation compared to W, thereby delaying senescence. Collectively, RB-Si synergistically regulates endogenous hormone metabolism to simultaneously delay ripening, reduce water loss, maintain firmness, optimize flavor, and enhance antioxidant capacity. This study elucidates the interaction mechanism between nano-SiO₂ and light quality, providing theoretical and technical support for the green preservation of horticultural crops. Full article

Drought stress is one of the most severe abiotic constraints limiting crop productivity worldwide, a challenge that is intensifying under ongoing climate change. In recent years, beneficial microorganisms have emerged as sustainable, nature-based tools to enhance plant drought tolerance and stabilize agricultural production under water-limited conditions. This review synthesizes current knowledge on the major groups of beneficial bacteria involved in drought stress mitigation, including plant growth-promoting rhizobacteria (PGPR), a functional subgroup of rhizosphere-associated microbes, endophytic bacteria, rhizosphere-associated microbes, and cyanobacteria, highlighting their primary physiological, biochemical, and soil-mediated mechanisms. These microorganisms enhance drought resilience through multiple complementary pathways, such as modulation of abscisic acid (ABA) and auxin (IAA) signaling, ACC deaminase activity, osmotic adjustment, antioxidant defense, improved nutrient acquisition, and enhancement of soil structure and water retention. The review further discusses practical application strategies, including seed inoculation, soil and root application, foliar spraying, the use of single strains versus microbial consortia, and advances in bioformulations and carrier materials that improve microbial survival and field efficacy. Emphasis is placed on recent experimental and field studies demonstrating the effectiveness of microbial inoculants under drought conditions. Collectively, the evidence highlights the potential of beneficial bacteria as key components of climate-resilient agriculture and underscores the need for integrated, formulation-driven approaches to translate laboratory success into consistent field performance. Full article