Search Results (591)

Drought stress severely limits plant growth and productivity, yet the molecular basis of drought tolerance and post-drought recovery remains incompletely understood in many forage legumes. Medicago ruthenica is a perennial legume native to arid and cold regions and exhibits strong drought resilience. Results: We integrated key physiological traits related to stomatal regulation, photosynthesis, osmotic adjustment and antioxidant defense with RNA-seq across four stages (well-watered control, CK; drought for 9 days, D9; drought for 12 days, D12; and rewatering for 4 days, RW). Drought triggered stage-dependent physiological shifts, and transcriptome profiling identified >3000 drought- and rewatering-responsive genes enriched in primary metabolism, redox homeostasis and hormone signaling. WGCNA highlighted two drought-associated modules (MEcyan and MEcoral1) and prioritized three hub transcription factors for functional validation: 861 (AP2/ERF), 22 (WRKY) and 89 (bZIP). Overexpression of each gene in tobacco improved drought tolerance, as indicated by enhanced growth/root traits, increased osmolyte accumulation and antioxidant enzyme activities, and reduced membrane damage. Conclusions: Together, these results provide an integrated view of drought stress response and recovery in M. ruthenica and identify 861, 22 and 89 as candidate regulatory genes for engineering drought resilience in legumes. Full article

Winter rapeseed (Brassica rapa L.) is an important crop for vegetable oil production in China. However, its productivity is frequently threatened by severe cold waves during winter. To investigate the role of the microtubule cytoskeleton in cold adaptation of winter rapeseed, a microtubule stabilizer paclitaxel (Tax) and a microtubule depolymerizer colchicine (Col) were sprayed on winter rapeseed and transgenic proBrAFP1 Arabidopsis, respectively. The mRNA levels of cold-induced genes, along with cell membrane stability, antioxidant enzyme activities, and hormone levels were assessed under cold stresses of 4 °C and −4 °C. The results showed that low temperature significantly activated the proBrAFP1 promoter activity and increased the mRNA levels of core cold signaling pathway genes, such as C-REPEAT BINDING FACTORS (CBFs), Cyclic Nucleotide-Gated Channel (CNGC), OPEN STOMATA 1 (OST1) and Inducer of CBF EXPRESSION 1 (ICE1). Notably, under low-temperature stress, exogenous application of the microtubule stabilizer Tax markedly suppressed proBrAFP1-driven reporter activity in transgenic Arabidopsis, with consistent inhibition observed across both stem and leaf tissues; meanwhile, the Tax application alleviated reactive oxygen species (ROS) accumulation and mitigated membrane damage. In contrast, under the same low-temperature stress, the Col treatment exacerbated oxidative stress, enhanced lipid peroxidation, and elevated membrane damage. Collectively, these findings establish that microtubule regulators play indispensable roles in the cold stress response of winter rapeseed. It provides new insights into the mechanism by which plant microtubule cytoskeleton regulators mediate the cold response. Full article

The prolonged low temperature in cold regions significantly inhibits the initiation of straw composting and lignocellulose degradation, thereby restricting straw resource utilization. In this study, 24 cellulose-degrading strains capable of stable growth under low-temperature conditions were screened. Based on multiple indicators, including carboxymethyl cellulase (CMCase) activity, strain LDT1 was identified as the best-performing isolate under low-temperature conditions and as Paenarthrobacter nitroguajacolicus. Subsequently, an efficient mutant strain, LDT1-8, was obtained through atmospheric and room-temperature plasma mutagenesis. The CMCase activity of LDT1-8 at 10 °C increased to 74.25 U/mL, representing a 21.72% increase compared to the wild-type strain. In a straw degradation system at 10 °C, LDT1-8 significantly accelerated early-stage degradation kinetics, with straw degradation rates at 3 and 6 d being 72.72% and 38.15% higher than those of the wild-type strain, respectively. Multi-enzyme profiling further indicated enhanced activities of multiple lignocellulose-degrading enzymes at low temperatures, accompanied by a partial shift in the optimal temperature of some enzymes (e.g., laccase) toward lower temperatures. Whole-genome sequencing revealed increased gene numbers related to energy, amino acid, and lipid metabolism in LDT1-8. Comparative genomic analysis suggested that mutations were mainly enriched in regulatory regions, accompanied by local structural variations. Transcriptional analyses further verified the coordinated upregulation of genes involved in cellulose and hemicellulose degradation, cold adaptation, and transcriptional and protein homeostasis processes in LDT1-8. Overall, this study provides an efficient microbial resource and a mechanistic basis for straw bioconversion in cold regions. Full article

The increasing demand for novel and healthy food options is largely driven by the rise in lifestyle diseases and the global challenges of climate change. Annually, wheat by-products (WBP) production surpasses 150 million tons, with an anticipated growth of 10 million tons per year from 2021 to 2027. This surge has attracted researchers’ interest in leveraging WBP as sustainable food resources that promote human health. This review evaluates the effects of thermal and emerging nonthermal processing technologies on WBP, focusing on enzyme activity, antinutritional factors, bioactive compounds, antioxidant activity, and functional properties. Notably, thermal degradation poses significant challenges due to the heat sensitivity of WBP’s nutritional components. Therefore, nonthermal techniques like high-intensity ultrasound, radiofrequency, and cold plasma are being explored for their potential to enhance nutritional quality and extend shelf life. Further investigation is crucial to comprehensively understand the effects of these innovative treatments on WBP. Such research could facilitate the incorporation of treated WBP into the food industry, leading to new health-promoting products. Full article

Pyruvate decarboxylase (PDC) is an intracellular non-oxidizing enzyme that relies on thiamine pyrophosphate (TPP), which is important for plant survival under anaerobic conditions and increasingly recognized for its role in broader stress reaction. However, the PDC gene family of tomato (Solanum lycopersicum), an important waterlogging-sensitive agricultural product, has not yet been discovered. In this study, eight SlPDC genes were discovered within the tomato genome. Gene structure analysis revealed that SlPDC members exhibited varying intron–exon configurations, with SlPDC8 possessing the most complex structure containing seven introns. Promoter analysis revealed a multitude of cis-acting elements responsive to light, hormones, and various stresses. Particularly, the promoter of SlPDC8 contains both ABRE and TGACG/CGTCA-motif. Tissue-specific expression profiles showed that SlPDC8 was mainly highly expressed in the roots. Expression profiling demonstrated that SlPDC genes respond divergently to different abiotic stresses, including salt, hydrogen peroxide (H₂O₂), drought, waterlogging, cold, heat, darkness, and UV radiation stresses. Notably, SlPDC1, SlPDC7, and SlPDC8 were significantly upregulated by waterlogging, with SlPDC8 showing the most robust induction. Functional validation through VIGS proved that SlPDC8-silenced plants exhibited significantly impaired growth, decreased photosynthetic pigment content, severe leaf wilting, and poor root development under waterlogging conditions compared to control plants. Furthermore, silencing SlPDC8 led to increased malondialdehyde (MDA) levels and decreased antioxidant enzyme activities, indicating heightened oxidative damage under waterlogging stress. We conclusively demonstrate that SlPDC8 plays a critical positive regulatory role in waterlogging tolerance by maintaining cellular homeostasis and enhancing antioxidant capacity. Full article

Hybridization is pivotal for germplasm innovation, yet how reciprocal crossing regulates digestive characteristics in sub-cold-water fish remains unclear. This study systematically compared differences in intestinal morphology, physiological function, and microbial community assembly among herbivorous Schizothorax prenanti, carnivorous S. davidi, and their reciprocal hybrids using histological analysis, digestive enzyme assays, and 16S rRNA sequencing. Results indicated that parental intestinal characteristics were highly consistent with their feeding habits. Orthogonal hybrids exhibited a mosaic phenotype, combining the maternal muscular gut structure with high paternal-like lipase activity, and were characterized by an enrichment of the potential probiotic Lactococcus. In contrast, reciprocal hybrids presented a mismatch between morphology and function: despite developed hindgut folds, key digestive enzyme activities were low, and the gut microbiota was dominated by environmental bacteria such as Methylobacterium. Our findings indicate a spatially dependent assembly dynamic: the host genetic background strongly drives microbiome divergence in the anterior segments (foregut and midgut), whereas the long-term administration of a standardized diet ultimately promotes structural convergence in the hindgut. The orthogonal cross yielded a phenotype characterized by an apparent co-occurrence of specific host enzymes and distinct microbiota, suggesting an inferred physiological potential for lipid digestion that requires further multi-omics validation. These findings provide preliminary insights into the associations between genetic background and intestinal traits, providing a theoretical basis for the targeted breeding of Schizothorax species. Full article

Taxillus chinensis (DC.) Danser is an important hemiparasitic medicinal plant whose propagation is severely limited by the desiccation sensitivity of its recalcitrant seeds. Dehydrins (DHNs), which protect plants against dehydration-induced stresses such as salinity, drought, and low temperatures, may play a critical role in protecting recalcitrant seeds. However, the role of DHNs in the seeds of T. chinensis remains unclear. In this study, a differentially expressed gene was identified from the seed transcriptome of T. chinensis and designated TcDHN1. Sequence alignment and phylogenetic analyses revealed that TcDHN1 encodes a dehydrin protein. Heterologous overexpression of TcDHN1 in Arabidopsis did not affect growth under normal conditions. Under salt, drought, and cold stresses, transgenic lines exhibited higher seed germination rates, longer primary roots, and improved seedling growth compared with wild-type (WT) plants. The transgenic lines showed significantly increased activities of antioxidant enzymes, including superoxide dismutase, catalase, and peroxidase. In addition, ectopic overexpression of TcDHN1 in Arabidopsis conferred enhanced tolerance to abiotic stresses compared to WT plants, accompanied by increased expression of the stress-responsive genes Responsive to Desiccation 29A (AtRD29A) and Heat Shock Protein 70-1 (AtHSP70-1). The above results indicate that TcDHN1 confers enhanced tolerance to abiotic stresses. This study provides a functional characterization of an abiotic stress-responsive gene from recalcitrant seeds and identifies a potential genetic resource for molecular breeding. This could potentially improve abiotic stress resistance in T. chinensis and related medicinal plants. Full article

Surface pitting is a physiological disorder characterized by depressions on the fruit surface, caused by subepidermal cell collapse and exacerbated during cold storage. This study evaluated antioxidant responses and cell wall disassembly in sweet cherry cultivars exhibiting contrasting susceptibility to surface pitting. Four cultivars were evaluated over two growing seasons under controlled cold storage and shelf-life conditions, with pitting experimentally induced. Surface pitting severity was strongly genotype-dependent. After 15 d at 1 °C in the first season, pitting severity was higher in ‘Sweetheart’ and ‘Lapins’ (2.4 and 1.9, respectively) than in ‘Regina’ (0.6), while in the second season, ‘Sweetheart’ reached the highest damage at shelf life (3.5) and ‘Santina’ remained low (0.8), confirming lower susceptibility in ‘Regina’ and ‘Santina’ than in ‘Sweetheart’ and ‘Lapins’. Cell wall-related traits and pectinolytic enzyme activities exhibited strong seasonal variability and were not consistently associated with pitting incidence. In contrast, resistant cultivars exhibited higher non-enzymatic antioxidant levels. Total phenolic content reached 4.1 ± 0.4 mg g⁻¹ in ‘Regina’ at the end of storage, while antioxidant capacity reached 51.5 ± 3.3% DPPH inhibition, up to 2-fold higher than susceptible cultivars. Enzymatic antioxidant activities were influenced by cultivar and season and showed limited association with pitting development. These results indicate that phenolic-based non-enzymatic antioxidant capacity plays a central role in conferring tolerance to surface pitting in sweet cherry during cold storage. Full article

Background: In this study, we aimed to determine whether cold-water swimming could serve as a potential strategy to enhance antioxidant capacity, improve NADH utilization in oxidative metabolism, and consequently lead to better muscle metabolism and improved mitochondrial function in the skeletal muscles of rats. We hypothesized that cold-water swimming may upregulate malate–aspartate shuttle (MAS) expression, leading to more efficient NADH utilization in oxidative pathways and thereby improving muscle metabolism and mitochondrial function. Methods: We analyzed the expression of all MAS components, as well as the expression of phosphofructokinase I (PFK-1)—a key regulatory enzyme of glycolysis (which, under oxidative conditions, serves as a source of NADH for MAS)—in the skeletal muscles of rats subjected to cold-water swimming training. The study involved 32 male and 32 female rats aged 15 months, randomly assigned to control sedentary animals, animals training in cold water at 5 ± 2 °C, or animals training in water at thermal comfort temperature (36 ± 2 °C). The rats underwent swimming training for nine weeks, gradually increasing the duration of the sessions from 2 min to 4 min per day, five days a week. Results: Our findings revealed increased expression of all MAS enzymes involved in the delivery of NADH to mitochondria, elevated expression of the active form of PFK-1 indicating intensified glycolysis, increased reactive oxygen species (ROS) production, and upregulation of antioxidant enzymes. Conclusions: Cold-water swimming can improve metabolism and enhance mitochondrial function in the muscles of older adult rats subjected to cold-water swimming training. Full article

Lemon (Citrus limon L.) is a widely cultivated citrus fruit valued for its nutritional and medicinal properties; however, it is highly perishable and prone to postharvest losses. This study aimed to evaluate the efficacy of natural edible coatings, chitosan (CS) and aloe vera gel (AV gel), applied individually and in combination, in preserving the postharvest quality of lemon fruits during 60 days of cold storage at 4 °C and 85% relative humidity. Nine treatments were tested, including a control, two concentrations of CS (2% and 3%), two concentrations of AV (10% and 15%), and four combinations of CS and AV gel. Various quality parameters were monitored at 0-, 10-, 20-, 30-, 40-, 50-, and 60-day intervals, including weight loss, fruit decay, juice content, firmness, total soluble solids (TSS), titratable acidity (TA), total sugars (TS), reducing sugars (RS), non-reducing sugars (NRS), total phenolic content (TPC), total antioxidant capacity (TAC), and antioxidant enzyme activities (catalase, peroxidase and superoxide dismutase) were monitored at 10-day intervals. The results demonstrated that the combined coating of 2% CS and 10% AV was the most effective in minimizing weight loss (34.25%) and decay incidence (9.22%) at day 60, while maintaining biochemical quality, including higher vitamin C content, phenolic content, and antioxidant activity. This research highlights the potential of CS and AV gel-based coatings as eco-friendly alternatives to synthetic preservatives for extending shelf life. Full article

Identifying the factors limiting cold resistance in augustinegrass is essential for expanding this shade-tolerant tropical turfgrass into temperate regions. We hypothesized that leaf potassium content is closely associated with its cold tolerance. To test this, we first analyzed the correlation between leaf potassium content and cold resistance across 30 germplasms, which confirmed a positive relationship and suggested that low potassium may limit cold tolerance. We then applied foliar potassium at 0, 15, 30, and 60 mM to increase leaf potassium content and evaluate its effect on cold resistance. The 15 mM treatment was most effective, increasing whole-plant fresh weight by 91.5% under cold stress compared to the control. To understand the underlying physiological mechanism, we measured the impact of foliar potassium on four key processes: photosynthesis (chlorophyll content, fluorescence, enzyme activity, stomatal aperture, gas exchange, and carbon assimilation products), osmotic adjustment (proline), membrane stability (relative conductivity and MDA), and ROS scavenging (SOD and CAT activity). Foliar potassium significantly enhanced photosynthetic performance; increased soluble sugars, starch, and proline; reduced MDA; and boosted both SOD and CAT activities. Pearson correlation analysis linked most physiological indicators to improved fresh weight. Critically, multiple linear regression identified leaf CAT activity as the primary factor, explaining 80% of the variation in cold resistance. qPCR analysis confirmed that CAT gene expression matched the increased enzyme activity. Field trials validated that a 15 mM potassium foliar spray effectively enhances cold tolerance. These findings demonstrate that leaf potassium is a major limiting factor for cold resistance in augustinegrass, and that foliar application of 15 mM potassium represents an effective management strategy, primarily by enhancing leaf CAT activity to improve ROS scavenging and overall stress tolerance. Full article

White-flowered alfalfa (Medicago sativa L.) persisting in Qinghai–Tibet Plateau’s saline–alkali habitats provides a unique model to explore floral color polymorphism-linked ecological adaptation. We systematically compared phenotypic, physiological, transcriptomic, and metabolomic profiles of white-flowered (WF) and purple-flowered (PF) alfalfa under high-altitude cold/saline–alkali field conditions (three biological replicates; Student’s t-test). WF showed a significant growth-defense trade-off: flower size and chlorophyll a content decreased by 18.9% and 46.0%, with reduced gibberellin levels, while jasmonic acid (36.3%), proline (51.5%), antioxidant enzyme activities, total flavonoids (17.7%), and condensed tannins (18.2%) were significantly increased (p < 0.001). Multi-omics analysis revealed phenylpropanoid pathway reprogramming (suppressed anthocyanin biosynthesis, precursor accumulation) and coordinated hormone signaling (jasmonic acid activation, salicylic acid inhibition). Our findings confirm the white-flower trait is not an isolated mutation. It is a key component of a coordinated adaptive syndrome, mediated by metabolic reprogramming and hormonal crosstalk. These results provide theoretical and technical support for breeding stress-resistant alfalfa varieties suitable for marginal land cultivation. Full article

The structural stability of lignocellulosic fibers in crop straw presents a significant challenge to its short-term biodegradation in natural environments, particularly in the cold regions of northern China. To isolate low-temperature straw-degrading bacteria, we selectively enriched microorganisms from straw-amended soils using lignocellulose as the sole carbon source. Three strains were isolated and identified: Stenotrophomonas sp. X24, Flavobacterium sp. X26, and Erwiniaceae bacterium X27. These strains were capable of growth and maize straw degradation within a 4–20 °C range and exhibited key cellulolytic activities (CMCase, FPase, and β-glucosidase). A synthetic three-strain mixture was assembled by combining these isolates in equal proportions. Solid-state fermentation (12 °C, 45 days) was used to assess straw degradation efficacy, while separate enzyme production experiments (12 °C, 3 days) were conducted to evaluate key cellulolytic activities and subsequently optimize culture conditions. The three-strain mixture achieved a net straw degradation rate of 30.93 ± 1.05%. Furthermore, optimization of culture conditions enhanced the carboxymethyl cellulase activity (CMCase) to a maximum of 24.51 ± 0.97 U/mL. The study demonstrates that the three-strain synthetic microbial mixture effectively degrades straw at low temperatures, offering a promising microbial resource to improve straw utilization and soil fertility in cold regions. Full article

Background: The JinEr mushroom results from the heterogeneous symbiosis of Naematelia aurantialba and Stereum hirsutum, with low-temperature storage being key for postharvest quality preservation. However, the species-specific low-temperature response patterns remain unclear. Methods: An integrated approach combining metabolomics, transcriptomics (dual-genome alignment), and spatially resolved enzyme assays was used to dissect responses at 0 °C and 4 °C. Results: The two fungi displayed distinct stress response tendencies under the studied conditions. N. aurantialba showed enhanced stress defense (DNA repair, antioxidant pathways) with defense-related enzyme activities concentrated in its apical/middle enrichment regions. S. hirsutum was observed to maintain overall metabolic activity at the pathway level, and its metabolic enzyme activities were predominant in the basal region. The symbiotic system exhibited temperature-dependent plasticity stress responses. Storage at 0 °C induced a survival-oriented response with slower crude polysaccharide degradation. In contrast, storage at 4 °C supported active metabolic defense coordination but more pronounced polysaccharide loss. Conclusions: These observed defense- and metabolism-biased differential responses suggest a cold stress-specific coordination working model within the symbiotic system under postharvest cold stress. A temperature of 0 °C is more suitable for enabling JinEr mushroom postharvest storage to retain polysaccharides. This study advances our understanding of heterogeneous symbiotic fungi’s postharvest biology and provides a temperature-targeted theoretical basis for storage optimization. Full article

Cold stress is a major limiting factor for growth and quality in chrysanthemum. Enhancing cold tolerance helps plants better cope with low-temperature stress, increase antioxidant enzyme activity, and effectively inhibit excessive accumulation of reactive oxygen species (ROS). This study identifies the transcription factor DgWRKY6 as a key positive regulator in chrysanthemum’s cold response. DgWRKY6 is localized in the nucleus and shows high expression levels in leaf tissue, which is strongly induced by cold stress. Cold treatment also activates its promoter region. Physiological assays demonstrate that overexpression of DgWRKY6 enhances ROS scavenging, reduces membrane damage, and improves cold tolerance by increasing the activities of glutathione S-transferase (GST) and peroxidase (POD), whereas DgWRKY6 knockout lines exhibit the opposite phenotype. Real-time quantitative PCR (RT-qPCR), yeast one-hybrid (Y1H), dual-luciferase reporter assays (Dual-LUC), and chromatin immunoprecipitation-qPCR (ChIP-qPCR) confirmed that DgWRKY6 directly binds to the W-box element and activates DgGST transcription. In conclusion, DgWRKY6 plays a positive regulatory role in enhancing cold tolerance in chrysanthemum by activating DgGST transcription in response to cold stress, ultimately increasing GST activity, reducing ROS accumulation, and enhancing antioxidant responses under low temperatures. This finding provides a valuable molecular target for cold tolerance breeding in chrysanthemum and other related horticultural crops. Full article