Search Results (902)

2,4-Dichlorophenoxyacetic acid (2,4-D) is a vital exogenous auxin for the induction and proliferation of litchi embryogenic callus. At present, its molecular regulation mechanism remains unclear. In this study, transcriptome sequencing samples were selected based on different cell growth phenotypes observed in ‘Feizixiao’ litchi embryogenic callus cultured in liquid medium with or without 2,4-D. By integrating transcriptome profiling with weighted gene co-expression network analysis (WGCNA), we identified key genes and signaling pathways dynamically responsive to 2,4-D concentration changes. We identified 558 commonly differentially expressed genes (DEGs), of which 117 were up-regulated and 387 were down-regulated; functional enrichment analysis revealed significant enrichment in the “plant hormone signal transduction” and “phenylpropanoid biosynthesis” pathways. In the former pathway, genes such as AUX28, GH3.17, GH3.6, and ARR5 were up-regulated; in the latter, by comparison, β-glucosidase 47 and Peroxidase 61 exhibited increased expression levels induced by 2,4-D. Furthermore, among these DEGs, 57 transcription factors belonged to 24 families. Notably, VRN1, FEZ, and DOF5.4 were significantly and rapidly induced by 2,4-D. WGCNA results demonstrated a significant positive correlation between the yellow module and 2,4-D treatment. Small heat shock protein (sHSP) genes constituted the core hub genes in the yellow module. Through Venn analysis of DEGs and key modules, 38 cross-genes were identified, of which non-specific lipid-transfer protein-like genes (nsLTP) were found to be specifically up-regulated without 2,4-D. The transcription factors and genes identified work in synergy to ensure the formation and sustained proliferation of embryogenic callus by precisely regulating the dynamic balance of auxin and cytokinin within cells and maintaining the stability of cell structure. Our findings provide a crucial theoretical foundation for understanding the molecular mechanism of 2,4-D in regulating litchi embryogenic callus proliferation. Full article

Elevated temperatures due to global climate change adversely affect plant growth and development, which has become a major factor restricting wheat (Triticum aestivum L.) production. Despite the introduction of dwarfing genes that have enhanced lodging resistance as well as productive potential in wheat breeding, lodging still affects wheat yields. Plant growth regulators are widely recognized as effective agents in mitigating crop lodging. Few studies have investigated the high-temperature lodging sensitivity of wheat genotypes from different breeding periods, nor have they examined how uniconazole-sucrose regulates lodging resistance under heat stress. To fill this research gap, an experiment was conducted in which two contrasting wheat genotypes from different periods, Bima 1 (BM1, ~135 cm tall, a historical genotype released in 1953, lodging-susceptible) and Shannong 28 (S28, ~75 cm tall, a modern genotype released in 2014, lodging-resistant), were exposed to high temperature stress combined with uniconazole-sucrose application. The results showed that high-temperature-induced increases in plant gravity center height, together with decreased stem diameter coefficient, stem plumpness, and lignin deposition, were the main factors responsible for the reduction in bending section factor and mechanical strength of wheat stems. These modifications are associated with reduced lodging resistance, increased susceptibility to lodging, and significant yield losses. Nevertheless, exogenous application of uniconazole-sucrose lowers plant gravity center height, enhances stem diameter coefficient, stem plumpness, and lignin content, thus alleviating lodging risk and boosting wheat yield under high temperature stress. High temperature stress was associated with downregulated relative expression levels of key genes involved in lignin metabolism and reduced activities of the corresponding key enzymes, as well as inhibited lignin biosynthesis and accumulation in stems and increased incidence of wheat lodging. Conversely, foliar spraying of uniconazole-sucrose alleviated these suppressive effects on lignin biosynthesis, thus enhancing stem mechanical strength and reducing the lodging index of wheat. Moreover, these indicators were more sensitive to heat stress or uniconazole-sucrose treatment in BM1. The two genotypes examined suggested a potential trend that S28 may exhibit reduced sensitivity to high temperature in terms of mechanical traits and lignin synthesis, which could contribute to enhanced lodging resistance under heat stress. Full article

Creeping bentgrass (Agrostis stolonifera), a widely used cool-season turfgrass, is highly susceptible to heat stress, which severely impairs its growth and physiological functions. In this study, two cultivars with contrasting heat tolerance, the heat-tolerant 13M and the heat-sensitive Seaside II (SII), were pretreated with diethyl aminoethyl hexanoate (DA-6) or distilled water and then exposed to either normal temperature or heat-stress conditions. Physiological traits and lipidomics were analyzed to investigate the regulatory role of DA-6 in lipid remodeling under high-temperature stress. Results showed that exogenous DA-6 application significantly mitigated physiological damage in both genotypes under heat stress. Under heat stress, compared with their corresponding untreated plants, DA-6 pretreatment increased the Fv/Fm by 15% in 13M and by 33% in SII; for the PI_ABS, DA-6 pretreatment increased it by 32% in 13M and by 55% in SII; for electrolyte leakage, DA-6 pretreatment reduced it by 24% in 13M and by 11% in SII. The analysis of lipidomics found that heat stress significantly reduced the accumulation of total lipids, phospholipids (PLs), glycolipids (GLs), and sphingolipids (SLs) in two genotypes, but under heat stress, 13M maintained significantly higher content of these lipids than SII. Exogenous DA-6 application significantly alleviated the heat-induced decline in photosynthesis-related glycolipids in SII. Specifically, MGDG, DGDG, and SQDG increased by 186%, 85%, and 32% in heat-stressed SII + DA-6, respectively, relative to heat-stressed SII without DA-6 pretreatment. In addition, DA-6 treatment also alleviated the heat-induced reduction in chloroplast- and mitochondria-associated lipids, including PG, LPG, and CL, in both genotypes. For heat-stressed 13M + DA-6, these lipids increased by 20%, 114%, and 22%, respectively, compared with heat-stressed 13M without DA-6 pretreatment; for heat-stressed SII + DA-6, they increased by 141%, 76%, and 184%, respectively, compared with heat-stressed SII without DA-6 pretreatment. These changes may contribute to improved stability of chloroplasts and mitochondria under heat stress. Furthermore, DA-6 application significantly promoted the accumulation of PC, PE, LPC, LPE, Cer, CerP, and Hex3Cer in both genotypes under heat stress. For 13M, the increases ranged from 18% to 120%; for SII, from 44% to 254%. In heat-stressed SII + DA-6 only, DA-6 also increased PA, PS, MLCL, DLCL, Hex1Cer, and Hex2Cer by 82%, 45%, 84%, 59%, 53%, and 41%, respectively, relative to heat-stressed SII without DA-6 pretreatment. These PLs and SLs are essential for maintaining plasma membrane integrity and mediating stress signal transduction. In addition, the application of DA-6 significantly reduced the heat-induced increase in unsaturation levels of total lipids in both genotypes, indicating that the DA-6 improved lipid saturation levels to better adapt to heat stress. Current findings demonstrated that the DA-6 application improved heat tolerance of creeping bentgrass associated with its regulation of lipid remodeling. Future investigations incorporating multi-omics approaches could comprehensively dissect the DA-6-induced signaling pathways and regulatory networks underlying heat-stress response in cool-season grass species. 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

Abscisic acid (ABA) regulates diverse aspects of plant growth and secondary metabolism, yet its concentration-dependent effects on rhizomatous spice crops remain poorly understood at the systems level. Here, we investigated the phenotypic, physiological, hormonal, and multi-omics responses of ginger (Zingiber officinale) to foliar-applied ABA across a concentration gradient. Exogenous ABA modulated ginger growth in a distinctly non-linear manner. Low-to-moderate concentrations (5–15 mg/L) significantly enhanced aboveground branching and belowground rhizome yield, whereas high concentration (35 mg/L) inhibited branching while promoting structural carbohydrate accumulation, revealing a concentration-dependent trade-off between growth and secondary wall deposition. Hormone profiling uncovered global reprogramming of the endogenous hormonal network, with optimal ABA (15 mg/L) coordinately elevating growth-promoting hormones and defense-related signals, while high concentrations suppressed multiple hormone pathways and triggered negative feedback inhibition of endogenous ABA biosynthesis. Integrated metabolomic and transcriptomic analyses identified convergent enrichment on phenylpropanoid biosynthesis, gingerol biosynthesis, and plant hormone signal transduction. Co-expression network analysis revealed a highly interconnected module of 583 genes linking hormone signaling to secondary metabolism, with coordinated up-regulation of key enzymes from phenylalanine ammonia-lyase (PAL) to polyketide synthase under 15 mg/L ABA explaining the 64% increase in 6-gingerol content. This study establishes a mechanistic chain from ABA perception to improved ginger yield and quality, mediated by hormonal crosstalk and transcriptional activation of the phenylpropanoid-gingerol network. We propose an “ABA optimization window” of 5–15 mg/L for precision cultivation of high-quality ginger, providing a systems-level framework for understanding hormone-mediated regulation of secondary metabolism in medicinal and spice crops. Full article

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

Against the backdrop of an accelerated green transition and increasingly stringent climate policies, climate transition risk has emerged as a significant exogenous shock to the financial system. Using a panel of 57 listed commercial banks in China over the period 2010–2024, this study investigates whether and how climate transition risk shapes bank risk-taking behavior and identifies the mechanisms involved. Empirical evidence shows that rising climate transition risk significantly lowers bank risk-taking, a conclusion that holds consistently under various endogeneity and robustness checks. Second, the evidence suggests that climate transition risk may indirectly reduce bank risk-taking by impairing growth capacity and increasing operational costs per unit. Third, moderating effect analysis reveals that higher levels of digital transformation and the implementation of the Paris Agreement help alleviate the adverse effects of climate transition risk, whereas increased economic policy uncertainty amplifies this effect. Fourth, heterogeneity analysis shows that large banks exhibit greater resilience, while banks with higher carbon-intensive exposure are more sensitive to climate transition risk. Overall, these findings provide empirical evidence and policy implications for enhancing climate-related financial regulation and facilitating the green transformation of the financial system. Full article

Sweet potato (Ipomoea batatas (L.) Lam) is an important food and energy crop. Soil salinization is a major abiotic stress that limits agricultural productivity and severely reduces yield of crops. Protein hydrolysates, as a class of natural biostimulants, have gained increasing attention for their potential to improve crop yield, quality and stress tolerance. This study investigated the effects of peptides from swine blood (PSB) on high salinity stress tolerance in sweet potato. Application of PSB promoted the growth of both aerial and underground parts of sweet potato under normal and high-salinity conditions. Further analysis revealed that, under high salinity stress, exogenous PSB up-regulated the expression of genes associated with stress responses, increased the accumulation of organic osmotic adjustment compounds such as free amino acids, promoted K⁺ uptake to elevate the K⁺/Na⁺ ratio, and enhanced the activity of key antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) involved in the reactive oxygen species-scavenging system. These biochemical responses contributed to maintaining cellular osmotic balance and redox homeostasis, protecting the cell membrane from damage while preserving its structural integrity and normal physiological functions, and improving photosynthetic efficiency, thereby enhancing high salinity stress tolerance in sweet potato. Thus, PSB holds significant potential as an effective natural biostimulant for sweet potato cultivation in saline soils. Full article

Salicylic acid (SA) is a key regulator of plant immunity and contributes to defence against Plasmodiophora brassicae, the causal agent of clubroot disease in canola (Brassica napus) and other crucifers. Exogenous SA applications have reduced clubroot severity in some Brassica pathosystems, yet the effectiveness of foliar SA treatment against the predominant resistance-breaking pathotype 3A in western Canada remains unclear. This study evaluated the effects of weekly foliar applications of 0, 1, 5, or 10 mM SA on clubroot development in two B. napus var. napobrassica cultivars under greenhouse and growth chamber conditions. Plants inoculated with pathotype 3A were assessed for disease severity, pathogen resting spore load, plant height, and transcript accumulation of SA-responsive genes. Overall, SA treatments resulted in modest reductions in disease severity and resting spore concentrations; however, treatment effects did not reach statistical significance in most cases. Collectively, foliar SA applications provided limited suppression of clubroot caused by pathotype 3A. Further optimization of SA concentration, timing, and delivery, particularly when targeting the root zone, may be required before SA can be considered a complementary tool in integrated clubroot management. Full article

The aroma quality of grape fruit is a crucial trait for table grapes, yet its relationship with plant disease resistance remains unclear. Using ‘Shine Muscat’ grapes as material, this study employed HS-SPME-GC-MS combined with odor activity value (OAV) and PLS-DA analysis to investigate the regulatory effects of different rootstocks and GA₃/MeJA treatments on volatile aroma compounds. Linalool and α-terpineol were selected as representative compounds for antibacterial experiments and gene expression analysis of terpenoid synthesis. Results indicate that the Lot rootstock and 15.25 mg·L⁻¹ GA₃ treatment significantly promoted the accumulation of terpenoid aroma compounds. Linalool exhibited significant inhibitory effects on the mycelial growth of Colletotrichum fructicola and induced upregulation of DXS, TPS56, and TPS gene expression. This study reveals a potential link between aroma metabolism and defense responses, providing a theoretical basis for synergistic optimization of grape aroma quality improvement and disease-resistant cultivation. Full article

Saline-alkali stress restricts crop yield by disrupting nutrient and water uptake, ionic balance, and oxidative homeostasis. Although myo-inositol enhances tolerance to abiotic stress, its role in sugar beet (Beta vulgaris L.) under saline-alkali conditions remains unclear. To investigate the effects of exogenous myo-inositol on sugar beet growth under saline-alkali soils, a pot experiment was conducted using six myo-inositol concentrations (0, 0.2, 0.4, 0.6, 0.8, and 1.0 g L⁻¹). Myo-inositol significantly influenced plant performance in a concentration-dependent manner. The 0.6 g L⁻¹ treatment produced the highest shoot and root fresh and dry weights, nearly doubling shoot biomass compared with the control. Shoot N and P contents increased markedly at 0.6 g L⁻¹, while their concentrations remained relatively stable, indicating biomass-driven nutrient accumulation. Myo-inositol reduced Na accumulation while maintaining stable K, Ca, and Mg concentrations, thereby improving ionic balance. Antioxidant capacity was enhanced, with superoxide dismutase and catalase activities significantly elevated. Root total length and surface area increased substantially, whereas specific root length and surface area decreased, suggesting improved root morphological development. Soil alkaline phosphatase activity was also stimulated at higher myo-inositol treatments. Overall, moderate myo-inositol application (with regression analysis indicating an optimum of approximately 0.56 g L⁻¹) improved sugar beet growth through enhanced nutrient acquisition, ionic balance, antioxidant capacity, and root development, offering practical insights for its use as a growth regulator in saline-alkali crop production. Full article

Exogenous glucose functions not only as a carbon source but also as a key signaling molecule involved in regulating root development and metabolism in plants. To elucidate the molecular mechanisms underlying this response in cherry rootstock (Prunus cerasus), we performed RNA-seq on lateral roots collected at 0, 6, 12, 24, 48, and 72 h after glucose treatment. Transcriptome profiling revealed a dynamic and sustained transcriptional reprogramming, with a total of 461 differentially expressed genes (DEGs) consistently altered across all post-treatment time points relative to the control (T0). Weighted gene co-expression network analysis identified five modules strongly correlated with glucose exposure, notably enriched for genes involved in nitrogen, carbon, and sulfur metabolism. Functional enrichment analyses further revealed a pronounced overrepresentation of pathways associated with nutrient utilization, as well as carbon fixation, glycolysis, amino acid biosynthesis, and stress-responsive processes such as glutathione metabolism and MAPK signaling. Intriguingly, key transcription factors and signaling components were consistently co-enriched across multiple functional categories, suggesting the presence of a tightly coordinated regulatory network that links sugar sensing to metabolic reprogramming, redox homeostasis, and developmental plasticity. Notably, glucose treatment induced both activation and repression of nitrogen-related genes in distinct co-expression modules, indicating fine-tuned modulation of nutrient uptake in response to carbon availability. Together, these findings suggest that exogenous glucose triggers a systems-level shift in root physiology, coordinating primary metabolism with stress adaptation and growth regulation through tightly interconnected carbon–nitrogen–sulfur metabolic circuits. Full article

Drought is a major limiting factor for apple growth and development. Abscisic acid (ABA) is a key hormone in plant abiotic stress responses, playing a vital role in mediating adaptation to drought. Malus sieversii, the wild ancestor of cultivated apple, exhibits superior drought tolerance. However, the specific ABA-dependent regulatory module underlying its exceptional drought tolerance remains to be elucidated. In this study, we investigated the role of ABA in the drought response of M. sieversii seedlings using a combination of exogenous ABA and the ABA biosynthesis inhibitor fluridone. Plants were subjected to four treatments: CK, PEG (20% PEG-6000), PEG+ABA (100 μM ABA) and PEG+FLU (100 μM fluridone). The results showed that ABA application significantly reduced the wilting rate by 45.53% and electrolyte leakage by 20.50% compared to the PEG treatment. Furthermore, it alleviated the decline in fresh weight and relative water content while reducing the accumulation of starch, sucrose, glucose, and fructose after seven days of stress. Conversely, FLU application intensified the adverse effects of drought. RNA-Seq analysis of the PEG+ABA vs. PEG comparison identified 5642 differentially expressed genes (DEGs), with significant enrichment in the starch and sucrose metabolism pathway, photosynthesis, carbon fixation, and MAPK signaling pathways. Exogenous ABA up-regulated BGLU23 while down-regulating BAM1. In contrast, no significant changes in their expression were observed under FLU treatment, suggesting their likely regulation in an ABA-dependent manner. In summary, ABA enhances osmotic-stress tolerance in M. sieversii through multiple pathways, among which starch and sucrose metabolism may represent a core and highly responsive regulatory pathway. Functional validation of key candidate genes BAM1 and BGLU23 remains an important direction for future investigation. These findings provide a theoretical basis for breeding drought-resistant apple rootstocks and for understanding ABA-mediated osmotic-stress tolerance mechanisms. Full article

Myo-inositol (MI) is recognized as a potential stress regulator capable of alleviating abiotic stress. The objective of this study is to analyze the role of MI in the salt stress response of Daucus carota L. and its potential mechanisms. “Hongxin Qicun” carrot seedlings were subjected to five treatments: control; salt stress (50 mM NaCl); and salt stress combined with 50, 100, or 200 μM of MI. Through an integrated approach combining physiological assays, non-invasive micro-test technology (NMT), and gene expression profiling, we found that salt stress severely inhibited seedling growth, disrupted K⁺/Na⁺ homeostasis, and triggered excessive H₂O₂ accumulation. Exogenous MI application mitigated these salt-induced damages, with 100 μM MI exerting the optimal effect. MI enhanced Na⁺ efflux and reduced K⁺ efflux in carrot roots under salt stress. Inhibitor experiments indicated that MI-promoted Na⁺ efflux relies on active transport via the plasma membrane (PM) Na⁺/H⁺ antiporter system, and qRT-PCR analysis showed that this response was accompanied by the upregulation of DcSOS1. Furthermore, MI contributes to K⁺ homeostasis by synergistically modulating PM H⁺-ATPase and high-affinity potassium transporters. The established proton gradient helps reduce salt-induced K⁺ loss through depolarization-activated potassium channels and non-selective cation channels. MI treatment decreased electrolyte leakage, malondialdehyde content, and H₂O₂ accumulation by enhancing the activities of the plant antioxidant defense system. Meanwhile, MI upregulated the expression of myo-inositol oxygenase (DcMIOXs) genes, which may contribute to osmotic balance maintenance and facilitate ROS scavenging. In conclusion, exogenous MI alleviates salt-induced physiological disorders in Daucus carota L. by coordinately regulating K⁺/Na⁺ and ROS homeostasis, with 100 μM identified as the optimal concentration for this effect. Full article

Calmodulin-like proteins (CMLs) serve as core components in plant calcium signal transduction pathways, and they extensively modulate plant growth, development, and adaptive responses to various abiotic stresses. In this study, we cloned the StCML19 gene from potato and generated stable transgenic Arabidopsis thaliana lines constitutively expressing this gene to investigate its functional role under drought stress. Transcriptome analysis revealed that StCML19 was up-regulated under drought conditions. Phenotypic assays showed that overexpressing StCML19 notably increased the seed germination rate and root length of transgenic Arabidopsis under mannitol-induced osmotic stress, and greatly improved the plant survival rate under severe soil drought stress. Physiological analysis showed that when put under drought stress, transgenic plants had higher proline content, better SOD, CAT, and POD activities, and significantly less malondialdehyde (MDA) accumulation than wild-type plants. In addition, overexpression of StCML19 led to greater plant sensitivity to exogenous ABA, with inhibited root growth and delayed seed germination as indicators. Conclusively, this study is the first to make sense of the biological function of potato StCML19 in the drought stress response and views StCML19 as a promising candidate gene for the genetic improvement of drought-tolerant potato varieties. Full article