Search Results (273)

Salinity restricts rice growth by disrupting cellular ion balance and promoting oxidative damage. Although exogenous melatonin can improve rice salt tolerance, whether expansion of the endogenous tryptophan pool enhances melatonin biosynthetic capacity and stress acclimation remains unclear. Here, we investigated a homozygous transgenic rice line constitutively expressing OASA1D, a feedback-insensitive D323N variant of the anthranilate synthase α-subunit OASA1. The OASA1D-expressing line exhibited strong resistance to 5-methyltryptophan and accumulated approximately twofold more tryptophan than wild-type plants in both shoots and roots under control and 150 mM NaCl conditions. The expanded tryptophan pool was accompanied by a 1.9–2.2-fold increase in endogenous melatonin and elevated expression of the melatonin biosynthetic genes OsTDC1, OsT5H, OsSNAT1, and OsASMT1. Under salt stress, OASA1D seedlings maintained greater shoot and root growth, biomass, and soil–plant analysis development (SPAD) values than wild-type seedlings. OASA1D also showed lower H₂O₂ and malondialdehyde accumulation and reduced electrolyte leakage, together with higher superoxide dismutase, catalase, and ascorbate peroxidase activities. Salt-induced expression of OsDREB2A, OsLEA3-1, OsP5CS1, OsWRKY45, OsHKT1;5, OsNHX1, and OsSOS1 was enhanced in OASA1D. Consistently, OASA1D shoots accumulated less Na⁺, retained more K⁺, and maintained a higher K⁺/Na⁺ ratio under salinity. Together, these results show that constitutive OASA1D expression expands the endogenous tryptophan pool and is associated with enhanced melatonin biosynthetic capacity, antioxidant defence, ionic homeostasis, and salt tolerance in rice. Full article

Salt stress severely limits plant growth, particularly in woody species. In this study, a time-course transcriptomic analysis (0–24 h NaCl treatment) revealed a clear time-dependent transcriptional reprogramming pattern in Betula platyphylla, characterized by rapid early activation followed by gradual stabilization. The response can be divided into three phases: early stress perception and signaling (1–3 h), mid-stage metabolic and hormonal reprogramming (5–9 h), and late-stage homeostasis and physiological adaptation (12–24 h). Early responses are dominated by signal transduction, the middle phase by metabolic reorganization and enhanced translation, and the late phase by redox and cellular homeostasis. Compared to the limited role of the Dehydration-Responsive Element-Binding protein (DREB) pathway, Abscisic acid (ABA) and Jasmonic acid (JA) signaling appear to play more central regulatory roles. Further analyses revealed the coordinated temporal activation of Reactive oxygen species (ROS), Salt Overly Sensitive (SOS), and ABA pathways: ROS shows an early burst followed by antioxidant activation; the SOS pathway regulates ion homeostasis via the Calcineurin B-like protein (CBL)-CBL-interacting protein kinase (CIPK) module; and ABA signaling progresses from biosynthesis to downstream transcriptional regulation. Protein interaction network analysis further identifies ABA signaling as a central hub integrating Ca²⁺ signaling, ROS metabolism, and ion transport. Overall, B. platyphylla responds to salt stress through a temporally coordinated regulatory network, providing new molecular insights into salt tolerance mechanisms in woody plants. Full article

Strawberry is a globally important yet stress-sensitive crop, increasingly threatened by combined abiotic and biotic stresses. Unlike single stresses, combined stresses elicit unique, non-additive responses through complex signaling and gene regulatory networks. This review synthesizes current knowledge on the molecular mechanisms underlying strawberry responses to combined stresses, focusing on signal perception and transduction as well as gene regulation. We examine how combined stresses are perceived by membrane-localized sensors and calcium channels, and how these signals are transduced through MAPK (mitogen-activated protein kinase) cascades, CDPKs (calcium-dependent protein kinases), and hormonal crosstalk involving ABA (abscisic acid), JA (jasmonic acid), and ethylene. At the gene regulation level, we discuss the roles of key transcription factors (WRKY, NAC (NAM, ATAF1, ATAF2 and CUC2), GRAS (GAI-RGA-and-SCR), DREB (Dehydration-Responsive Element-Binding protein), bZIP (basic leucine zipper transcription factor), CAMTA (calmodulin-binding transcription activator), ARF (auxin response factor), and LAV (Leafy Cotyledon2–Abscisic Acid Insensitive3–Val)), transcriptional cascades, epigenetic regulation via DNA methylation, and post-transcriptional (miRNAs such as Fan-miR73) and post-translational (ubiquitination and phosphorylation) control mechanisms. The review also evaluates emerging mitigation strategies informed by these molecular insights, including genomic selection, and explores future directions such as CRISPR (clustered regularly interspaced short palindromic repeats)-based genome editing and multi-omics integration. We conclude that understanding the integrated signaling and gene regulatory networks is essential for developing climate-resilient strawberry cultivars capable of withstanding increasingly complex stress combinations. Full article

Cereal crops including wheat, rice, maize, barley, and sorghum collectively supply most global caloric and protein requirements, yet their productivity is increasingly constrained by combined abiotic stresses that co-occur under field conditions. Simultaneous drought, heat, salinity, and cold impose yield losses that consistently exceed those caused by individual stresses and elicit molecular responses that are qualitatively distinct from single-stress reactions and cannot be inferred from them. Despite this agronomic reality, the molecular mechanisms governing combined stress responses in cereals remain poorly resolved, and no integrated framework connecting the transcriptional, epigenetic, and genome-editing dimensions of combined stress tolerance has previously been articulated for this crop group. This review proposes a three-tier integrated framework for understanding and engineering combined abiotic stress tolerance in major cereals. The first tier encompasses transcription factor networks, including bZIP, WRKY, NAC, AP2/ERF, DREB, MYB, and HSF families, that translate combined stress signals into transcriptional reprogramming through ABA-dependent and ABA-independent pathways, hormonal crosstalk, and osmoprotectant and antioxidant defence systems. The second tier addresses the epigenetic regulatory layer, encompassing DNA methylation, histone modifications, and non-coding RNA pathways that gate TF binding site accessibility and encode stress memory in cereals. The third tier examines CRISPR-based tools, including multiplexed Cas9 editing and dCas9-based epigenome editing, that engineer validated targets from both tiers, while confronting polyploid off-target effects, growth penalties, and a laboratory-to-field validation gap. The three tiers are mechanistically coupled, with TF activity shaping epigenetic landscapes, epigenetic states gating TF access, and both providing precision engineering targets. Critical gaps include the absence of combined-stress epigenomic datasets, limited characterisation in barley and sorghum, and early-stage combined-stress-specific strategies. Full article

Drought stress severely restricts the growth and yield of woody nut crops. The xyloglucan endotransglucosylase/hydrolase (XTH) gene family participates in plant developmental and stress responses, yet its functions in pecan (Carya illinoinensis) under water limitation remain largely uncharacterized. Here, we performed a genome-wide identification of the XTH family in pecan, identifying 34 members distributed across four phylogenetic clades. Transcriptome-based expression analysis showed that several CiXTH genes responded to drought stress, among which CiXTH18 exhibited strong and sustained induction. To investigate its function, CiXTH18 was overexpressed in Arabidopsis thaliana. Under PEG-induced osmotic stress, CiXTH18-overexpressing lines exhibited significantly prolonged primary root lengths compared to wild-type plants. Furthermore, detached leaf assays revealed that transgenic plants had lower water loss rates under dehydration conditions. In addition, DAB staining indicated reduced H₂O₂ accumulation in CiXTH18-overexpressing plants under osmotic stress. Quantitative real-time PCR analysis revealed that the drought-responsive gene DREB2A and the ABA biosynthesis-related gene NCED3 were more strongly induced in transgenic lines than in wild-type plants after PEG treatment. Promoter activity assays confirmed that CiXTH18 was responsive to ABA treatment. Collectively, our findings indicate that heterologous expression of CiXTH18 is associated with improved performance of Arabidopsis under PEG-induced osmotic stress and support CiXTH18 as a promising candidate for further functional investigation. Full article

Water deficit is one of the most critical factors for determining the growth and yield of sugarcane. Understanding the physiological and molecular mechanisms of sugarcane responses is essential for developing resilient cultivars. In this study, three sugarcane cultivars, NX04 (sensitive), BL (moderate), and NXI-4T (tolerant), were grown in a greenhouse for 2 months and then subjected to drought stress for 8 days after planting. Morphological variation showed that the tolerant sugarcane cultivar exhibits a longer root system and delays leaf chlorosis and rolling. Malondialdehyde (MDA) content was increased in the sensitive and moderate cultivars, although it slightly increased in the tolerant cultivars at 8 days after drought stress. The increase was accompanied by increases in proline content and in gene expression of the catalase (Cat) and ascorbate peroxidase (Apx) across all cultivars, which protect cells from oxidative damage. Interestingly, the expression of the photosynthetic Pepc (phosphoenolpyruvate carboxylase) and Sps (sucrose-phosphate synthase) genes was significantly decreased, whereas SPS activity increased under drought stress. This implies that the SPS protein may be regulated through post-translational modification. The expression of transcription factors (TFs) of NAC, rather than DREB, was significantly upregulated in the tolerant cultivar under 8 days of drought stress, in line with the delay of chlorosis. Full article

The AP2/ERF transcription factor family is one of the largest transcription factor families in plants and plays essential roles in growth and development. Chili pepper, as a representative member of the Solanaceae family, is an important vegetable crop with enormous economic value. In this study, using the recently released gap-free telomere-to-telomere genome assembly of pepper, we re-annotated the AP2/ERF transcription factor family and identified 155 high-confidence members. Phylogenetic analysis classified these genes into five subfamilies: AP2 (19), ERF (82), DREB (51), RAV (1), and Soloist (2). Comprehensive analyses of gene structure, conserved motifs, chromosomal distribution, collinearity, cis-elements, and expression profiles revealed substantial structural conservation and functional diversification within the family. Expression profiling highlighted CaBBM, a key member of the AP2 subfamily, as a candidate developmental regulator, prompting further functional characterization. Expression analyses using qRT-PCR and promoter–GUS assays showed that CaBBM was preferentially expressed in stamens, while subcellular localization assays confirmed its nuclear localization. Preliminary analysis of biological functions suggests that heterologous expression of CaBBM in Arabidopsis can lead to phenotypes such as shorter primary roots, smaller leaves and floral organs, and decreased pollen number. In addition, yeast two-hybrid screening identified 12 candidate interacting proteins. These results provide a comprehensive framework for understanding the AP2/ERF family in chili pepper and lay a foundation for elucidating the function and regulatory mechanisms of CaBBM. Full article

Salinity stress affects not only the survival and productivity of halophytic plants, but also the composition, structure and processability of their biomass. In Salicornia spp., salt-induced regulation of ion transport, osmotic adjustment, reactive oxygen species signaling, antioxidant defense, and cell wall remodeling can directly influence residual salinity, water retention, texture, extractability, drying behavior, and oxidative stability of plant biomass. However, most existing transcriptomic studies of Salicornia and related halophytes have focused mainly on salt tolerance mechanisms, whereas the connection between stress-regulated molecular networks and processing-related biomass traits remains insufficiently systematized. This review addresses this gap by proposing a mechanistic framework that links salinity perception, ROS-mediated signaling, ABA and MAPK pathways, antioxidant gene families, transcription factor networks and processing-oriented quality traits. Special attention is given to enzymatic antioxidant systems, including SOD, CAT, APX, POD and components of the ascorbate-glutathione cycle, as well as to non-enzymatic defense mechanisms involving ascorbate, glutathione, phenolic compounds, carotenoids, proline and glycine betaine. The review also discusses the regulatory roles of WRKY, DREB/CBF, NAC, bZIP and MYB transcription factor families as molecular control points connecting salinity stress responses with downstream metabolic and structural traits. Network-based approaches, including WGCNA, pathway signatures and transcript panels, are considered more informative than single-gene markers for predicting complex quality traits in Salicornia biomass. In addition, recent genomic and computational strategies, including CRISPR/Cas-mediated functional validation, GWAS, genomic selection, multi-omics integration and AI-assisted modeling, are discussed as emerging tools for candidate-gene prioritization and predictive assessment of stress-dependent biomass quality. Overall, this review shifts the interpretation of Salicornia transcriptomics from a descriptive salt-tolerance model toward a mechanistic and application-oriented framework for improving halophytic raw materials for food, feed and bioprocessing applications. Full article

Amino acid permeases (AAPs) facilitate the uptake and transmembrane transport of amino acids and play critical roles in regulating plant growth, development, and stress responses. However, the characteristics and functions of the AAP gene in pepper remain unclear. In this study, nine CaAAP genes were identified within the pepper (Capsicum annuum) genome and designated as CaAAP1-CaAAP9. Phylogenetic analysis revealed that CaAAP6, CaAAP7, and CaAAP9 belong to subfamily I, CaAAP8 is the sole member of subfamily III-E, and the remaining genes are classified within subfamily II. Collinearity analysis indicated the presence of both tandem and segmental duplication events among the nine CaAAP genes in pepper, as well as four and seven duplicated gene pairs between Arabidopsis and tomato, respectively. Expression profiling demonstrated that CaAAP genes exhibit pronounced tissue-specific expression patterns and differential expression in response to exogenous plant hormones and various abiotic stress treatments. Notably, drought stress elicited a significant up-regulation of CaAAP6 expression. Functional characterization confirmed that CaAAP6 localizes to the cell membrane. Silencing of CaAAP6 resulted in a significant reduction in plant drought tolerance, accompanied by disrupted tissue architecture, and stomatal closure. Furthermore, the concentrations of H₂O₂, O₂^•−, and MDA exhibited increases of 76.19%, 108.52%, and 20.23%, respectively. Concurrently, the activities of SOD, POD, and CAT decreased by 42.32%, 64.09%, and 109.64%, respectively. Additionally, the transcriptional levels of the CaRD22, CaRD29B, and CaDREB2A genes were reduced by 135.56%, 67.19%, and 37.91%, respectively, compared to the control plants. Collectively, these findings provide initial functional evidence that CaAAP6 contributes to drought tolerance in pepper. Full article

Regionally, compound agroecological stress arising from both natural and anthropogenic emergy inputs may influence maize transcriptomic responses; however, evidence across multiple scales remains limited. We developed a reproducible five-step framework integrating a macro-level compound stress index, molecular response modules, cross-scale coupling, spatial continuity, and independent field validation. Nine variables (emergy indicators ELR, Fn, and NEYR; climate; soil; and terrain) were PCA-weighted into a Composite Abiotic Stress Intensity Index (CASI; first three PCs = 83.7%; and prefecture-level Moran’s I = 0.463). Across 15 public RNA-seq datasets (286 samples), WGCNA identified five separable modules (drought–heat, reproductive stage heat, low nitrogen/phosphorus, osmotic salt, and chronic compound), 270 core genes, and four cross-module hubs (ZmDREB2A, ZmHSFA2, ZmWRKY33, and ZmNRT2.1). With n = 21, the sCCA (r₁ = 0.81, permutation p = 0.003; LOO-CV r = 0.71), random forest, and spatial error model all confirmed coupling between ELR and the drought–heat module (β = 0.51, p = 0.008). PLS-DA four-zone partitioning (Q² = 0.548) and a county-level second-order trend surface (R² = 0.67) verified spatial continuity. GSVA on five independent field RNA-seq datasets yielded 74.4 to 82.8% core gene directional consistency and Cliff’s δ of 0.59 to 0.68 (large effect), avoiding circular reasoning. The framework enables molecular analysis for precision agriculture and climate-resilient breeding. Full article

Abiotic stresses severely restrict plant growth, development, and crop yield. Histone modification functions as a key epigenetic regulator in plant stress adaptation. This review systematically summarizes the major types of histone modifications (e.g., acetylation, methylation) and their catalytic enzyme systems. It clarifies the regulatory patterns of chromatin remodeling and gene expression under diverse abiotic stress conditions, like extreme temperature changes, persistent drought, elevated salinity, and heavy metal exposure, and reveals the crosstalk networks between histone modifications and ABA, CBF/DREB, and ROS signaling pathways. It also discusses the transgenerational inheritance of stress-induced histone modification variations and their molecular basis, and introduces the application of CRISPR/Cas9 and dCas9-based epigenetic editing in improving crop stress resistance. Currently, research on histone modification in plateau crops remains fragmented: studies mostly focus on single stress rather than combined multiple abiotic stresses, lack tissue-specific epigenetic regulatory maps for native plateau plants, and the field application of epigenetic breeding technologies is seriously insufficient. Considering the compound stresses, including low temperature, drought, salinization, and heavy metals, on the Qinghai–Tibet Plateau, this review identifies current research gaps, such as tissue specificity, multi-stress crosstalk, and field application, and proposes future directions, including multi-omics analysis, stress adaptation mechanisms of plateau plants, and precise epigenetic breeding. Overall, this review fills the research gap of systematic collation on histone-mediated stress tolerance epigenetics under plateau combined abiotic stresses, and provides a theoretical reference for epigenetic research on plant stress resistance and for the improvement of plateau crops. Full article

Tree peony (Paeonia suffruticosa Andr.) is a traditional ornamental plant of high economic and cultural value, but its flower longevity is often limited by petal water loss. Cuticular wax serves as an essential barrier against non-stomatal water loss, and the AP2/EREBP (APETALA2/Ethylene-Responsive Element Binding Protein) transcription factor family is known to regulate wax biosynthesis. However, little information is available on the roles of AP2/EREBP genes in petal cuticle formation in tree peony. In this study, we performed transcriptome sequencing on petals of the tree peony cultivar ‘Bai Wang Shi Zi’ at three developmental stages (early, middle, and late). Using the assembled transcriptomic data, we identified 29 high-confidence AP2/EREBP family members, which were phylogenetically classified into AP2, ERF, and DREB subfamilies. Expression profiling revealed that 18 of these genes exhibited stage-specific expression patterns during petal development. Among them, two homologs of Arabidopsis SHN1 (SHINE 1) and WRI3 (WRINKLED 3), designated PsSHN1 and PsWRI3, showed peak expression at the middle stage. By co-expression analysis and phylogenetic comparison, three downstream candidate genes were identified and named PsCER2, PsKAS1, and PsLTPG1, based on their homology with known wax-related genes. Dual-luciferase reporter assays indicated that PsSHN1 and PsWRI3 can activate the promoters of PsCER2, PsKAS1, and PsLTPG1, suggesting a possible cooperative regulation of cuticle formation. Collectively, our findings provide promising candidate genes for prolonging floral lifespan by improving petal cuticular wax accumulation, and lay a preliminary foundation for molecular breeding and quality improvement of tree peony and other ornamental flowers. Full article

Heat stress severely constrains wheat productivity, yet the mechanisms underlying thermotolerance remain incompletely understood. This study integrated physiological, biochemical, molecular, and ultrastructural analyses to characterize heat-stress responses in four bread wheat (Triticum aestivum L.) genotypes contrasting in heat tolerance. Membrane injury was assessed by membrane damage rate, lipid peroxidation by malondialdehyde accumulation, antioxidant defense by SOD, CAT, GPX, and BPX activities, and stress-responsive regulation by qRT-PCR analysis of DREB, HSP16.9, and SOD isoforms. HSP16.9 protein accumulation was further evaluated by Western blotting. Heat stress increased membrane damage and MDA accumulation in all genotypes; however, tolerant Murov 2 and Zirva 85 showed lower oxidative membrane injury than sensitive Aran and Gyzyl bugda. Thermotolerance was associated with stronger antioxidant activation, enhanced DREB and HSP16.9 induction, and more coordinated FeSOD and MnSOD expression. The HSP16.9 protein accumulated after heat treatment, supporting its role as a stress-responsive molecular chaperone. Separate correlation analyses of tolerant and sensitive genotypes revealed stronger coordination among transcriptional, chaperone-related, and antioxidant markers in tolerant genotypes, whereas sensitive genotypes showed a more fragmented response. Microscopy further showed better preservation of chloroplast, mitochondrial, and mesophyll organization in the tolerant genotype relative to the sensitive counterpart, indicating integrated cellular protection. Together, these responses define a coordinated tolerance strategy that may guide the selection of heat-resilient wheat genotypes. Full article

The rhizosphere microbiome and phytohormone signaling are critical determinants of plant growth and stress resilience. This study evaluated the combined effects of Streptomyces sp. HU2014 and coronatine (COR) on maize (Zea mays L.) seedlings. Four treatments were established: control (CK), COR seed soaking (Cor), HU2014 soil inoculation (S), and combined S + Cor (SCor). Growth parameters, chlorophyll content, and antioxidant/oxidative stress markers were measured, and root and leaf transcriptomes, together with root metabolomes, were compared between SCor and CK, followed by qRT-PCR validation. Compared with CK, SCor treatment significantly increased stem diameter (~60%), plant height (~20%), and relative chlorophyll content (SPAD, ~50%). Soluble sugar levels were elevated by over 40% in both leaves and roots, accompanied by tissue-specific modulation of antioxidant enzymes. Transcriptomic analysis of SCor vs. CK revealed 2459 differentially expressed genes (DEGs) in leaves and 3444 DEGs in roots; leaves exhibited upregulation of photosynthetic pigment metabolism (porphyrin and carotenoid pathways) and volatile defense compounds (alkaloids and monoterpenoids), whereas roots showed enrichment in phenylpropanoid/flavonoid biosynthesis, benzoxazinoid synthesis, and starch/sucrose metabolism. Metabolomics of SCor vs. CK identified 526 differentially accumulated metabolites (DAMs) in roots, with significant enrichment in aminoacyl-tRNA biosynthesis, phenylalanine metabolism, and linoleic acid metabolism. Integrative multi-omics analysis further revealed that the JA precursor 13-epi-12-oxo-phytodienoic acid co-clustered with stress-responsive transcription factors (e.g., DREB1C), while tricarboxylic acid (TCA) intermediates and phenylpropanoid metabolites were linked to energy and lignin biosynthesis genes. qRT-PCR confirmed the expression trends of 14 out of 15 tested genes. Collectively, combined HU2014 and COR application triggers tissue-specific transcriptional and metabolic reprogramming in maize, coupling JA-mediated stress signaling with enhanced carbon metabolism and secondary defense compound synthesis to promote rhizosphere adaptation and seedling vigor. Full article

Dry direct seeding (DDS) is a water-saving and high-efficiency rice cultivation system. However, drought stress during DDS severely constrains seedling establishment. This study used the conventional rice variety Zhonghua 11 (ZH11) and the drought-tolerant hybrid Hanyou 73 to investigate the effects of exogenous silicon (Si) on seed germination and seedling growth under drought stress, and to explore the underlying mechanisms of Si-enhanced drought tolerance. Drought stress was imposed using PEG-6000 simulation and pot experiments with different soil relative water contents (60%, 45%, 25%, and 10%). Si treatment significantly alleviated simulated drought inhibition of seed germination, increasing germination percentage and index, improving seedling growth in both varieties. Under simulated DDS conditions, Si significantly improved plant height, biomass, and root development, while maintaining higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and chlorophyll content. Meanwhile, Si reduced oxidative damage by promoting proline accumulation, enhancing peroxidase (POD) and catalase (CAT) activities in both leaves and roots, reducing malondialdehyde (MDA) accumulation, and upregulating the expression of key drought-responsive genes (SNAC1, DREB1A, SKIPa, P5CS2). Furthermore, Si upregulated the expression of genes involved in abscisic acid (ABA) (ABA1, ABA2, MHZ5, ABI3) and jasmonic acid (JA) (AOS2, AOS3, JAR1, JAR2, MYC2, COI1a) biosynthesis and signaling. Compared with the wild-type, the ABA signaling mutant abi3 and the JA signaling mutant myc2 exhibited significantly attenuated improvement of plant growth by Si treatment. Collectively, Si enhances antioxidant capacity and osmotic adjustment, maintains photosynthetic function, and is associated with the activation of ABA and JA signaling pathways, which together alleviate the inhibition of rice seedling establishment under DDS-associated drought stress. Our findings provide a theoretical basis for the application of Si fertilizer in DDS rice production. Full article