Search Results (812)

Medicinal agroforestry system contributes to enhancing agricultural productivity. In this process, allelochemicals play a crucial role, and certain allelochemicals can even promote the growth of intercropped plants significantly. Previous studies by our group have shown that fig tree (Ficus carica L.) extract promotes woad (Isatis indigotica Fort.) growth significantly. However, the specific mechanism by which fig tree influences the growth of woad remains unclear. In this study, we demonstrated the growth-promoting effects of fig tree extract on woad through sterile seedling cultivation experiments and identified three allelochemicals—psoralen, bergapten, and umbelliferone. To further validate the growth-promoting activity of these compounds, a pot experiment was conducted by exogenously applying the three allelochemicals. The results revealed that all three allelochemicals derived from fig tree exhibited a property of concentration dependence on the growth of woad seedlings. Specifically, it shows an obvious promoting effect at the low concentration, while exhibiting inhibiting effects at high concentrations. Among them, the magnitude of the promoting effect, from strongest to weakest, was as follows: bergapten, psoralen, and umbelliferon. This study primarily aimed to elucidate the growth-promoting effect of woad induced by allelochemicals present in fig tree extracts and to clarify how these allelochemicals regulate woad growth. Full article

Background: It is established that depression significantly contributes to tumor development, yet its molecular link to gastric cancer progression remains unclear. Methods: In this study, we examined depression-related gene expression profiles in relation to clinical prognosis and identified estradiol and the NOTCH3 gene as critical factors involved in gastric cancer progression in the context of depression. Using a chronic unpredictable stress-induced tumor-bearing mouse model, we validated the impact of depression on tumor development. Additionally, the underlying molecular mechanisms were explored through a range of biological techniques, including Western blotting, immunofluorescence, flow cytometry and immunohistochemistry. Results: Depression significantly accelerated gastric cancer growth in our mouse model, characterized by decreased estradiol levels and increased NOTCH3 expression. Importantly, exogenous estradiol supplementation effectively counteracted depression-induced tumor growth. Consistently, in vitro studies showed that estradiol treatment suppressed NOTCH3 expression in HGC-27 and YTN3 cell lines. Furthermore, NOTCH3 was shown to modulate intracellular reactive oxygen species levels by regulating SOD2 activity, thereby influencing cell proliferation. Conclusions: This work identified the estrogen/NOTCH3 signaling as a key link between depression and gastric cancer development, offering promising therapeutic strategies to improve outcomes for patients suffering from psychological disorders. Full article

Salt stress is a major abiotic factor that inhibits plant growth. Melatonin (MT), an important plant growth regulator, can effectively enhance plant stress resistance. Festuca elata, a turfgrass species widely used in urban landscaping, was selected for this study to evaluate the regulatory effects of exogenous MT at different concentrations on its growth and development under salt stress. Indoor pot experiments were conducted using Festuca elata as the plant material. The experiment included a 250 mM NaCl salt-stress treatment and foliar application of five MT concentrations (0 μM, 50 μM, 150 μM, 250 μM, and 350 μM) to assess their effects under salt stress. The results showed that salt stress severely inhibited the growth of Festuca elata, while all tested MT concentrations significantly alleviated the damage. MT treatments improved leaf area and plant height and increased relative water content, soluble protein, proline, chlorophyll, and carotenoid contents. Additionally, MT reduced malondialdehyde accumulation and enhanced superoxide dismutase and peroxidase activities. Among the tested concentrations, 150 μM MT showed the most effective alleviation of salt stress, indicating its strong potential for promoting Festuca elata cultivation in saline environments. Full article

In recent years, high temperature and drought have severely impacted the growth and development of loquat [Eriobotrya japonica (Thunb.) Lindl.] plants. Although dopamine can improve the stress resistance of plants, its role in combined stress requires further exploration. This study investigated the alleviative effect and mechanism of exogenous dopamine on loquat seedlings subjected to the combined stress of high temperature and drought. The combined stress significantly reduced root viability, photosynthetic pigment content, and net photosynthetic rate (Pn) while markedly increasing reactive oxygen species (ROS) levels, thiobarbituric acid-reactive substances (TBARS) content, and electrolyte leakage (EL). The seedlings exhibited pronounced wilting symptoms, along with markedly reduced root surface area and volume. Dopamine treatment significantly alleviated combined stress-induced damage. This mitigation was manifested through substantially enhanced root viability, photosynthetic pigment content, Pn, antioxidant enzyme activities, and osmotic adjustment substances concomitantly with marked reductions in ROS, TBARS content, and EL. Dopamine significantly reduced seedling wilting severity and improved root morphological parameters. This study demonstrates that dopamine enhances loquat seedlings’ tolerance to combined stress through coordinated mechanisms: maintaining photosynthetic pigments and improving stomatal conductance to sustain photosynthetic efficiency, enhancing antioxidant enzyme activity and ROS scavenging capacity to mitigate oxidative damage, and promoting osmotic solute accumulation for osmotic potential regulation. Full article

Drought stress caused by continuous global warming poses a severe challenge to the growth and development of Nitraria tangutorum. Abscisic acid has an important regulatory function in the process of plants responding to drought stress. This study took the N. tangutorum seedlings of Zhangye provenance 2-17-16 genealogy as the research object to explore the physiological mechanism of how different concentrations of exogenous ABA alleviate drought damage in N. tangutorum. The results showed that exogenous ABA could promote the growth and increase the leaf relative water content of N. tangutorum seedlings under drought stress. It alleviates the photosynthetic inhibition phenomenon of N. tangutorum seedlings under drought stress by regulating the photoprotective mechanism and energy distribution efficiency of photosystem II. It also alleviates the drought damage of N. tangutorum by increasing the content of osmotic-adjustment substance contents such as soluble sugar, soluble protein, proline, and starch, as well as enhancing the activity of antioxidant enzymes such as POD, SOD, and CAT. The comprehensive analysis showed that 20 μM and 30 μM ABA have the best alleviating effects on the drought damage of N. tangutorum seedlings. This study provides a theoretical basis for the restoration, propagation, and protection of N. tangutorum, and it is of great significance for maintaining the balance and stability of desert ecosystems. Full article

Prunus humilis is rich in various minerals, organic acids, proteins, and carbohydrates, but its sour taste limits fresh consumption and industry growth. Methyl jasmonate, a plant growth regulator known to enhance fruit quality, has been studied in other fruits, but research on its effects on P. humilis has not yet been reported. This experiment used the P. humilis cultivar ‘Nongda No. 4’ as the material. During the fruit development stages (the pre-young fruit stage and pre-coloring and enlargement stage), the fruiting branches were sprayed with a 20 mg/L methyl jasmonate solution four times. The results indicate that exogenous methyl jasmonate increases the content of various sugar components in P. humilis fruits throughout their development, with a particularly strong effect in the later stages of fruit development. It effectively reduces the content of malic acid and citric acid in these later stages while significantly enhancing flavor-related attributes such as the sweetness, sugar–acid ratio, and sweetness–acid ratio. Moreover, methyl jasmonate markedly promoted the accumulation of different forms of calcium in the fruit. Specifically, at the fully ripe stage, the total sugar content increased significantly by 18.64% (p < 0.05), the total acid content decreased by 15.95% (p < 0.05), and the total calcium content increased by 55.98% (p < 0.05). Correlation and principal component analyses revealed that sugars, acids, and calcium are closely linked in P. humilis, and exogenous treatment with methyl jasmonate effectively improved the overall quality score of sugars, acids, and calcium in the fruit throughout its development. In conclusion, exogenous methyl jasmonate can effectively improve the sugar–acid quality, flavor, and calcium content of P. humilis fruits. This provides a theoretical foundation for cultivation management, quality enhancement, and the breeding of fresh-eating cultivars. Full article

Drought stress limits seedling growth, hindering morphological development and population establishment. Artocarpus nanchuanensis, a critically endangered species endemic to the karst regions of southwest China, exhibits poor population structure and limited natural regeneration in the wild, with water deficit during the seedling stage identified as a major factor contributing to its endangered status. Elucidating the physiological and molecular mechanisms underlying drought tolerance in A. nanchuanensis seedlings is essential for improving their drought adaptability and facilitating population recovery. In this study, 72 two-year-old seedlings were divided into two groups: drought (PEG) and ethephon (PEG + Ethephon), and subjected to drought-rehydration experiments. The results showed that exogenous application of 100 mg·L⁻¹ ethephon significantly improved stomatal conductance and photosynthetic pigment content in A. nanchuanensis seedlings. Under drought stress, the PEG + Ethephon group exhibited rapid stomatal closure, maintaining water balance and higher photosynthetic pigment levels. After rehydration, the PEG + Ethephon group significantly outperformed the PEG group in terms of photosynthetic rate. Ethephon treatment reduced H₂O₂ and MDA levels, enhanced antioxidant enzyme activity (SOD, CAT, POD, GR), and increased osmotic regulator activity (soluble sugars, soluble proteins, and proline), improving ROS-scavenging capacity and reducing oxidative damage. Ethephon application significantly enhanced ethylene accumulation in seedlings, while drought stress stimulated the concentrations of key ethylene biosynthetic enzymes (SAMS, ACS, and ACO), thereby further contributing to improved drought resistance. Transcriptomic data revealed that drought stress significantly upregulated key ethylene biosynthesis genes, with expression levels increasing with stress duration and rapidly decreasing after rehydration. WGCNA analysis identified eight key drought-resistance genes, providing valuable targets for future research. This study provides the first mechanistic insight into the physiological and molecular responses of A. nanchuanensis seedlings to drought and rehydration, underscoring the central role of endogenous ethylene in drought tolerance. Ethephon treatment effectively enhanced ethylene accumulation and biosynthetic enzyme activity, thereby improving drought adaptability. These findings lay a theoretical foundation for subsequent molecular functional studies and the conservation biology of this endangered species. Full article

The germination and elongation of maize in the early growth stage are closely related to the elongation of the mesocotyl, which is one of the first parts to sense external temperature, aside from the coleoptile. Low-temperature (LT, 10~15 °C) stress can significantly affect the survival and growth of maize seedlings. Additionally, brassinosteroids (BRs) have been used in recent years to help alleviate damage caused by LT in various plants. However, the interaction among LT, BRs, and sugar remains unclear. Therefore, we examined the relationships among the contents of glucose, sucrose, and starch, along with the changes in differentially expressed genes (DEGs) involved in starch and sucrose metabolism and glycolysis/gluconeogenesis pathways. Compared to CK (0 μM 24-epibrassinolide (EBR) application at 25 °C), the contents of glucose and sucrose increased by 0.26, 0.47, and 0.70 mg g⁻¹ FW and 0.80, 0.30, and 0.61 mg g⁻¹ FW, respectively, under the CKE (2.0 μM 24-epibrassinolide (EBR) application at 25 °C), LT (0 μM 24-epibrassinolide (EBR) application at 10 °C), and LTE (2.0 μM 24-epibrassinolide (EBR) application at 10 °C) treatments. However, starch contents decreased under LT and LTE treatments, by −20.54% and −0.20%, respectively, compared to CK. This suggests that sugar signaling and metabolism play key roles in regulating LT tolerance, and the application of EBR may alleviate LT damage by regulating sugar accumulation levels. Furthermore, 108 DEGs were identified in the starch and sucrose metabolism pathways, along with 23 in glycolysis, with 65 DEGs at the transcriptome level. The common Zm00001d042146 (hexokinase-3) in both pathways is usually down-regulated, and the degree of down-regulation when EBR is added is less than under LT alone. Additionally, key genes such as Zm00001d021598 (glucan endo-1,3-beta-glucosidase 3), Zm00001d034017 (uncharacterized LOC541703), and Zm00001d029091 (sucrose synthase 2) were differentially expressed under LT, with their expression levels decreasing further when EBR was added. In conclusion, our results provide a new direction into the molecular mechanisms by which exogenous EBR application enhances low-temperature tolerance in maize seedlings. Full article

Plants are frequently exposed to a range of abiotic stresses, including drought, salinity, extreme temperatures, and heavy metals, that severely impair their growth and productivity. Among the adaptive mechanisms that plants have evolved, the accumulation of glycine betaine (GB), a naturally occurring, zwitterionic, and chemically stable osmoprotectant, has been widely recognized as a key strategy for stress tolerance. In higher plants, GB is primarily synthesized via the two-step oxidation of choline, catalyzed by choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). GB contributes to cellular homeostasis by modulating osmotic balance, regulating ion flux, scavenging reactive oxygen species (ROS), enhancing antioxidant defense systems, and stabilizing proteins and membrane structures. Both exogenous application of GB and genetic engineering approaches aimed at enhancing endogenous GB biosynthesis have been shown to significantly improve plant tolerance to a variety of abiotic stresses. In this review, we provide a comprehensive overview of recent advances in the understanding of GB biosynthesis, its regulatory mechanisms, and its multifaceted roles in plant stress responses. We also highlight emerging prospects for leveraging GB-centered strategies to enhance crop resilience in challenging environmental conditions. Full article

Dehydration response element binding proteins (DREBs) have been identified as major regulators of cold acclimatization in many angiosperms. Cold stress is one of the primary abiotic stresses affecting kiwifruit growth and development. However, kiwifruit is currently one of the most widely consumed fruits worldwide because of its high nutritional value. 5-Aminolevulinic acid (5-ALA) is a nonprotein amino acid known for its distinct promotional effects on plant resistance, growth, and development. However, studies on the function of the kiwifruit DREB gene in alleviating low-temperature stress in its seedlings via exogenous 5-ALA have not been reported. Therefore, in this study, we performed a genome-wide identification of DREB gene family members in kiwifruit and analyzed the regulatory effects of exogenous 5-ALA on kiwifruit DREB genes under low-temperature stress. A total of 193 DREB genes were identified on 29 chromosomes. Phylogenetic analysis classified these genes into six subfamilies. Although there were some differences in cis-elements among subfamilies, all of them contained more biotic or abiotic stresses and hormone-related cis-acting elements. GO and KEGG enrichment analyses revealed that AcDREB plays an essential role in hormone signaling, metabolic processes, and the response to adverse stress. Under low-temperature stress, the application of exogenous 5-ALA inhibited the accumulation of APX and DHAR, promoted an increase in chlorophyll, and increased the accumulation of enzymes and substances such as 5-ALA, MDHAR, GR, ASA, GAH, and GSSH, thereby accelerating ROS scavenging and increasing the cold hardiness of kiwifruits. Functional analysis revealed that 46 differentially expressed DREB genes, especially those encoding AcDREB69, AcDREB92, and AcDREB148, which are involved in ethylene signaling and defense signaling, and, after the transcription of downstream target genes is activated, are involved in the regulation of low-temperature-stressed kiwifruits by exogenous 5-ALA, thus improving the cold tolerance of kiwifruits. Notably, AcDREB69, AcDREB92, and AcDREB148 could serve as key genes for cold tolerance. This study is the first to investigate the function of AcDREB genes involved in the role of exogenous 5-ALA in regulating low-temperature stress, revealing the regulatory mechanism by which DREB is involved in the ability of exogenous 5-ALA to alleviate low-temperature stress. Full article

Lead (Pb) and cadmium (Cd) severely impair rice growth, yield, and grain quality. This study assessed the role of exogenous gamma-aminobutyric acid (GABA) in mitigating Pb and Cd toxicity in aromatic rice ‘Guixiangzhan’. Treatments included the control (no Pb, Cd, or GABA), GABA (1 mM), Pb (800 mg/kg of soil)+GABA, Cd (75 mg/kg of soil)+GABA, Pb+Cd+GABA, Pb, Cd, and Pb+Cd without GABA. GABA improved chlorophyll and carotenoid, protein, proline and GABA contents whilst reducing oxidative stress under Pb/Cd toxicity. GABA application regulated antioxidant enzyme activities, net photosynthesis, and gas exchange, while its effects on nitrate reductase and glutamine synthetase were variable. Compared with Pb+Cd, the grain yields were 34.03%, 31.94%, 15.88%, 24.86%, and 17.32% higher in (Pb, Cd, Pb+Cd)+GABA, Pb, and Cd treatments, respectively. Furthermore, GABA reduced Pb and Cd accumulation in aboveground parts, while Ca, Mg, Fe, Cu, Zn, and Mn levels varied across treatments. Cd translocation was more from root-to-leaves, while Pb translocation was more from leaves-to-grains. Grain Pb and Cd positively correlated with their root, stem, and leaf contents but negatively with mineral nutrients. Overall, exogenous GABA mitigated Pb and Cd toxicity in aromatic rice. Full article

Soil salinity severely impairs plant growth, and polyamines such as spermidine (Spd) are known to bolster stress tolerance by acting as osmoprotectants and signaling molecules. Using TiO₂ enrichment, iTRAQ quantification, and bioinformatics analysis, we identified 870 proteins and 157 differentially phosphorylated proteins. Functional annotation showed that salt stress activated key components of the Salt Overly Sensitive pathway, particularly serine threonine kinases (SOS2) and Ca²⁺ binding sensors (SOS3). Among thirty-six SOS-associated kinases detected, eight SOS2 isoforms, four MAPKs, and two SOS3 homologs were significantly upregulated by NaCl, and Spd further increased the phosphorylation of six SOS2 proteins and one SOS3 protein under salt stress, with no detectable effect on SOS1. qRT PCR revealed enhanced expression of MAPKs and calcium-dependent protein kinases, suggesting a phosphorylation-centered model in which Spd amplifies Ca²⁺-mediated SOS signaling and reinforces ion homeostasis through coordinated transcriptional priming and post-translational control. Additional, proteins involved in protein synthesis and turnover (ribosomal subunits, translation initiation factors, ubiquitin–proteasome components), DNA replication and transcription, and RNA processing showed differential expression under salt or Spd treatment. Central metabolic pathways were reprogrammed, involving glycolysis, the TCA cycle, the pentose phosphate pathway, as well as ammonium transporters and amino acid biosynthetic enzymes. These findings indicate that exogenous Spd regulated phosphorylation-mediated networks involving the SOS signaling pathway, protein homeostasis, and metabolism, thereby enhancing cucumber salt tolerance. Full article

Fibro-adipogenic progenitor cells (FAPs) support muscle tissue homeostasis, regulate muscle growth, injury repair, and fibrosis, and activate muscle progenitor cell differentiation to promote regeneration. We aimed to investigate the effects of co-culturing FAPs with muscle satellite cells (MuSCs) on myogenic differentiation. Proteomic profiling of co-culture supernatants identified significant DCX, IMP2A, NUDT16L1, SLC38A2, and IL-6 upregulation. Comparative transcriptomics of mono-cultured versus co-cultured MuSCs revealed differential expression of oxidative stress-related genes (HMOX1, ALOX5, GSTM3, TRPM2, PADI1, and CTSL). Pathway enrichment analyses highlighted cell cycle regulation, TNF signaling, and ferroptosis. Gene ontology analysis of MuSCs indicated significant gene enrichment in myosin-related components. Combined transcriptomic and proteomic analyses demonstrated HO-1 downregulation at the transcriptional and translational levels, with altered pathways being predominantly related to myosin filament, muscle system process, and muscle contraction cellular components. HO-1 knockdown reduced intracellular iron accumulation in MuSCs, suppressing iron-dependent autophagy. This alleviated oxidative stress and promoted myogenic differentiation. Exogenous IL-6 (0.1 ng/mL) downregulated HO-1 expression, initiating an identical regulatory cascade, while HO-1 overexpression reversed the IL-6-mediated reduction in the expression of the autophagy markers LC3 and ATG5, suppressing myogenic enhancement. This establishes the co-culture-induced IL-6/HO-1 axis as a core regulator of iron-dependent oxidative stress and autophagy during myogenic differentiation. Full article

Macadamia (Macadamia integrifolia), Macadamia tetraphylla and hybrids, a crop of high economic and nutritional importance, faces challenges with low fruit set rates and severe fruit drop. To address this, we investigated the effects of exogenous plant growth regulators (PGRs) and boron fertilizer on the development, fruit set, and yield of the A4 macadamia variety. The study was conducted in 2024 at the Lujiangba research base (China, Yunnan Province). Five treatments were applied during key growth stages: boron (B), brassinosteroids (BR), N-(2-Chloro-4-pyridyl)-N’-phenylurea (CPPU), 6-benzylaminopurine (6-BA), and gibberellic acid (GA₃). Growth stages include flower bud formation, peak flowering, and fruiting. Our findings revealed that B treatment significantly increased pollen viability (95.69% improvement) and raceme length (23.97% increase), while BR enhanced flower count per raceme (26.37% increase) and CPPU improved flower retention (10.53% increase). Additionally, GA₃ and 6-BA promoted leaf expansion in new shoots, increasing leaf length by 39.83% and 31.39%, respectively. Notably, B application significantly improved total yield (43.11% increase) and fruit number (39.12% increase), whereas BR maximized nut shell diameter (5.7% increase) and individual nut weight (19.9% increase). Furthermore, CPPU and 6-BA markedly improved initial fruit set rates, while GA₃, BR, and B effectively reduced early fruit drop. Physiological analyses indicated that elevated soluble sugars and proteins in flowers correlated with higher initial fruit set, whereas increased endogenous cytokinin and GA₃ levels improved fruit retention and reduced drop rates. Based on these findings, we propose an integrated approach to optimize productivity: applying 0.02% B at the floral bud stage, 2 mg/L 6-BA at full bloom, and a combination of 0.02% B and 0.2 mL/L BR during early fruit set. This strategy not only enhances yield but also mitigates fruit drop, offering practical solutions for macadamia production. Full article

One of the important traits of many plant growth-promoting rhizobacteria (PGPR) is the biocontrol of phytopathogens. Some PGPR metabolize phytohormone abscisic acid (ABA); however, the role of this trait in plant–microbe interactions is scarcely understood. Phytopathogenic fungi produce ABA and use this property as a negative regulator of plant resistance. Therefore, interactions between ABA-producing necrotrophic phytopathogen Botrytis sp. BA3 with ABA-metabolizing rhizobacterium Rhodococcus sp. P1Y were studied in a batch culture and in gnotobiotic hydroponics with sunflower seedlings. Rhizobacterium P1Y possessed no antifungal activity against BA3 and metabolized ABA, which was synthesized by BA3 in vitro and in associations with sunflower plants infected with this fungus. Inoculation with BA3 and the application of exogenous ABA increased the root ABA concentration and inhibited root and shoot growth, suggesting the involvement of this phytohormone in the pathogenesis process. Strain P1Y eliminated negative effects of BA3 and exogenous ABA on root ABA concentration and plant growth. Both microorganisms significantly modulated the hormonal status of plants, affecting indole-3-acetic, salicylic, jasmonic and gibberellic acids, as well as cytokinins concentrations in sunflower roots and/or shoots. The hormonal effects were complex and could be due to the production of phytohormones by microorganisms, changes in ABA concentrations and multiple levels of crosstalk in hormone networks regulating plant defense. The results suggest the counteraction of rhizobacteria to ABA-producing phytopathogenic fungi through the metabolism of fungal ABA. This expands our understanding of the mechanisms related to the biocontrol of phytopathogens by PGPR. Full article