Search Results (241)

Apple represents one of the most economically significant fruit crops worldwide, and the performance of its scion is largely determined by the physiological and genetic characteristics of the rootstock. Despite their superior ecological adaptability and growth-controlling attributes, many dwarfing apple rootstocks exhibit inherently poor rooting competence, which poses a critical limitation to their large-scale clonal propagation and commercial utilization. Adventitious root (AR) formation is a pivotal yet highly intricate developmental process that governs the success of asexual propagation. It is orchestrated by a complex network of hormonal signaling, transcriptional regulation, metabolic reprogramming, and environmental cues. Over the past decade, remarkable advances have elucidated the physiological, biochemical, and molecular frameworks underpinning AR formation in apple rootstocks. This review provides an integrative synthesis of current progress in vegetative propagation techniques—including cutting, layering, and tissue culture—and systematically dissects the endogenous and exogenous factors influencing AR development. Particular emphasis is placed on the regulatory interplay among phytohormones, carbohydrate and nitrogen metabolism, phenolic compounds, transcription factors (such as WUSCHEL-RELATED HOMEOBOX (WOX), LATERAL ORGAN BOUNDARIES DOMAIN (LBD), and RESPONSE FACTOR (ARF families), and epigenetic modulators that collectively coordinate root induction and emergence. Furthermore, emerging insights into multi-omics integration and genotype-specific molecular regulation are discussed as strategic pathways toward enhancing propagation efficiency. Collectively, this review establishes a comprehensive theoretical framework for optimizing the asexual propagation of apple rootstocks and provides critical molecular guidance for breeding novel, easy-to-root genotypes that can drive the sustainable intensification of global apple production. Full article

Auxenochlorella pyrenoidosa, a promising edible bioresource, can be efficiently and safely cultivated using exogenous phytohormones to enhance its productivity. This study employed multi-omics analysis to systematically investigate the effects and mechanisms of exogenous trans-Zeatin (tZ) on the growth and metabolism of A. pyrenoidosa. Results demonstrated that 10 mg/L tZ significantly promoted algal growth, increasing biomass by 166 ± 3.35% at 72 hours (h), while concurrently elevating cellular soluble protein (SP), carbohydrate (CHO), and chlorophyll a (Chla) content. tZ also strengthened the antioxidant defense system, evidenced by reduced reactive oxygen species (ROS) levels, enhanced activities of antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)), upregulation of glutathione metabolism, and decreased lipid peroxidation product (malondialdehyde (MDA)). Furthermore, tZ activated key metabolic pathways, including nitrogen metabolism, photosynthetic carbon fixation, and porphyrin biosynthesis, leading to the accumulation of arginine and polyamines, etc. This study reveals that tZ promotes microalgal growth by coordinately regulating carbon–nitrogen metabolic networks and antioxidant systems, providing a theoretical foundation for phytohormone-augmented microalgae cultivation technologies. Full article

Heat stress exacerbated by global warming severely impairs the growth and tea quality of the tea plant (Camellia sinensis). Trehalose is pivotal for regulating plant growth and enhancing stress resistance. However, the molecular characteristics, expression patterns, and regulatory mechanisms of trehalose metabolism genes in tea plants under heat stress remain unclear. Therefore, this study conducted a comprehensive investigation of trehalose metabolism genes in the Tieguanyin tea plant genome. A total of 30 trehalose metabolism genes were identified, including 17 trehalose-6-phosphate synthase (CsTPS), 9 trehalose-6-phosphate phosphatase (CsTPP), and 4 trehalase (CsTRE) genes. These genes were characterized in terms of their chromosomal locations and gene structures; the encoded proteins were characterized in terms of their phylogenetic relationships, conserved motifs, functional domains, physicochemical properties, and subcellular distributions. The results showed that these genes exhibit family-specific structural and functional features, laying a foundation for further functional studies. Collinearity analysis identified 20 homologous gene pairs between tea plants and Arabidopsis thaliana, significantly more than the 3 pairs with Oryza sativa, suggesting a closer evolutionary relationship with A. thaliana. Additionally, five intraspecific duplicated gene pairs were identified, all with Ka/Ks values < 1, indicating they have undergone strong purifying selection during evolution, leading to functional stability. Cis-acting element analysis revealed abundant stress-responsive, light-responsive, and phytohormone-responsive elements in the promoter regions of these trehalose metabolism genes, indicating their potential involvement in tea plant stress resistance regulation. Differential expression analyses under heat stress with exogenous trehalose treatment (CK: control, T: water-sprayed heat stress, TT: 5.0 mM trehalose-sprayed heat stress) identified six differentially expressed genes (DEGs). We further analyzed the expression patterns of these DEGs. Specifically, CsTPS1, CsTPS5, and CsTPS12 were increasingly upregulated in CK, T, and TT, respectively, while CsTPP1 and CsTPP2 were upregulated in TT relative to T. Additionally, CsTRE1, CsTRE2, and CsTRE4 showed downregulation in TT compared to T, though they were not classified as DEGs. These findings indicate that exogenous trehalose application modulates trehalose metabolism by promoting CsTPS and CsTPP expression while inhibiting CsTRE expression, thereby increasing endogenous trehalose content in tea plants under heat stress. Yeast heat stress tolerance assays confirmed that CsTPS1, CsTPS5, CsTPS12, and CsTPP1 enhanced yeast survival at 38 °C, verifying their function in improving organismal heat stress tolerance. In conclusion, these results clarify the roles of trehalose metabolism genes in tea plants’ heat stress response, demonstrating that exogenous trehalose modulates their expression to increase endogenous trehalose levels. This study provides a theoretical foundation for exploring trehalose-mediated heat stress resistance mechanisms and improving tea plant stress tolerance via genetic engineering. Full article

To elucidate the comprehensive mechanism by which nitric oxide (NO) enhances low-temperature tolerance in cucumber, we utilized two cucumber cultivars (Jinyan No. 4 and Jinyou No. 1) as experimental materials. By integrating transcriptomic analysis with physiological indicators, we investigated the physiological and molecular mechanisms underlying the NO-mediated improvement of cold tolerance. Both molecular and physiological data revealed that phytohormone signal transduction and alpha-linolenic acid metabolism were significantly affected by low-temperature stress alone and in combination with exogenous SNP treatment in both cultivars. Under low-temperature stress, most transcripts associated with abscisic acid (ABA) biosynthesis, ABA signal transduction, and flavonoid biosynthesis were coordinately downregulated in cucumber. In contrast, transcripts related to secondary metabolism, lipid metabolism, glutathione biosynthesis, and hormone signal transduction—including salicylic acid (SA), ethylene (ETH), gibberellin (GA), and jasmonic acid (JA) pathways—were coordinately upregulated. Additionally, exogenous SNP was found to regulate both phytohormone signal transduction and endogenous hormone levels. These results suggest that exogenous NO improves low-temperature tolerance in cucumber seedlings primarily by modulating phytohormone signaling and secondary metabolism. Full article

Cucumis sativus L. is a globally important vegetable crop that occupies a significant position in protected agriculture due to its high nutritional value, short cultivation cycle, and considerable economic benefits. As a cold-sensitive plant, however, cucumber is highly susceptible to low-temperature stress. which can severely inhibit growth and development, hinder seed germination, and reduce photosynthetic efficiency. Under low-temperature stress, cucumber plants typically incur damage to cellular membrane structures, experience an accumulation of reactive oxygen species (ROS), exhibit a disruption in hormonal homeostasis, and suffer from the inhibition of pivotal metabolic pathways. In response, cucumber plants activate an array of resistance mechanisms, encompassing osmotic adjustment, reinforcement of the antioxidant system, and modulation of cold-responsive gene expression. This review summarizes the physiological and molecular mechanisms underlying cucumber’s response to low-temperature stress, aiming to provide effective strategies for improving abiotic stress resistance. The main findings are as follows: (1) Low-temperature stress damages cucumber cell membranes, suppresses photosynthesis and respiration, suppresses water and nutrient uptake/transport, and suppresses growth retardation. (2) Cucumber counters these adverse effects by orchestrating the accumulation of osmoregulators (e.g., soluble sugars, proline), activating activation defenses (e.g., SOD, CAT), and rebalancing its phytohormone network (e.g., ABA, GA, SA, ethylene). (3) At the molecular level, cucumber activates low-temperature-responsive genes (e.g., COR, GoIS) through transcription factors such as CBF, MYB, and WRKY, thereby enhancing cold tolerance. (4) Application of exogenous protectants (e.g., hydrogen sulfide, melatonin, oligosaccharides) significantly improves cucumber’s low-temperature tolerance by modulating the antioxidant system, promoting osmoregulatory substances accumulation, and regulating hormone signaling pathways. Future research should focus on elucidating the molecular regulatory network in cucumber under low-temperature stress and developing gene editing with multi-omics techniques to advance the development of cold-resistant cultivars and cultivation practices. This study offers a scientific foundation for research on cucumber cold tolerance and proposes potential solutions to agricultural challenges in the context of global climate change. Full article

Salt stress is a major abiotic factor limiting crop productivity worldwide, as it disrupts plant growth, metabolism, and survival. In this study, we report that the genes PvPR10-2 and PvPR10-3 were significantly up-regulated in bean leaves and stems in response to combined salt and jasmonic acid (NaCl–JA) treatment. Foliar application of JA with salt induced physiological alterations, including stem growth inhibition, H₂O₂ accumulation, and activation of antioxidant enzymes. To investigate the role of PvPR10-3 in response to salt and phytohormones, we introduced this gene into Arabidopsis and found that its heterologous expression conferred salt tolerance to the transgenic lines. Interestingly, exogenous JA contributed to salt tolerance by reducing H₂O₂ levels, inducing ROS-scavenging enzymes, and promoting the accumulation of phenolic compounds and ABA. Furthermore, gene expression analysis of the transgenic lines revealed that PvPR10-3 expression under NaCl–JA stress is associated with the induction of JA-related genes like MYC2, JAZ2, JAZ11, and JAZ12, as well as SA-responsive genes, like ALD1 and TGA2, and two ABA-independent components DREB2A and ERD1, suggesting potential coordination between JA, ABA, and SA signaling in salt stress response. Additionally, key flowering regulators (FT, GI) were upregulated in transgenic lines under NaCl–JA treatment, suggesting a previously unexplored link between salt tolerance pathways and the regulation of flowering time. Taken together, our findings suggest a role of PvPR10-3 in enhancing salt stress tolerance and the involvement of exogenous JA in tolerance potentially by modulating ROS balance, hormone-associated gene expression, and protective secondary metabolites. Full article

Jujube (Ziziphus jujuba Mill.) is an important economic fruit tree in China, and its in vitro culture technology is the key to achieving large-scale seedling cultivation. PGRs (Plant growth regulators) play a central regulatory role in all stages of jujube micropropagation, including explant initiation, proliferation, and rooting. This article provides a comprehensive overview of recent advances in in vitro culture of jujube, with a focus on the recommended exogenous phytohormone ratios, their effects, and underlying regulatory mechanisms across distinct varieties during the key stages such as in vitro culture, shoot proliferation, and root formation. The primary culture of most jujube varieties usually employs the MS medium, and it is recommended that auxin and cytokinin be used in combination. During the initial cultivation stage, the use of NAA (1-naphthaleneacetic acid) or IBA (indole butyric acid) is recommended at concentrations ranging from 0.1 to 1.0 mg/L. At the same time, 6-BA (6-benzylaminopurine) is suggested, with a concentration range of 0.5 to 2.5 mg/L. In the subculture multiplication of most jujube varieties, MS medium is used, and auxin (such as NAA, IBA), and TDZ (thidiazuron) and cytokinin (e.g., 6-BA) are used in combination. The recommended concentration range for auxin remains between 0.1 and 1.0 mg/L, and for cytokinin 6-BA between 0.5 and 2.5 mg/L, while the recommended concentration of TDZ is suggested to be below 0.01 mg/L. Rooting induction for most jujube varieties has predominantly been achieved using 1/2 MS medium, with growth regulator concentrations typically ranging from 0.5 to 3.0 mg/L. Full article

Sedum alfredii is a cadmium (Cd) hyperaccumulator, but the regulatory mechanisms linking phytohormones and redox balance to Cd transporter expression remain unclear. In this study, we omitted external cadmium (Cd) stress to isolate and examine the interplay between phytohormone and reactive oxygen species (ROS) signaling. Exogenous treatments with abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellic acid (GA₃), trans-zeatin (t-Z), and H₂O₂ were combined with analyses of hormone levels, antioxidant enzyme activities, and transporter gene expression. Correlation and PLS-SEM analyses identified the CAT–H₂O₂ module as a key node: ABA and IAA enhanced CAT activity and alleviated ROS-mediated repression of transporters, while GA₃ and t-Z exerted opposite effects. Functional validation using an H₂O₂ scavenger revealed that the regulation of HMA3 and Nramp5 by ABA and t-Z is H₂O₂-dependent. In contrast, IAA modulates Nramp5 through a ROS-independent pathway, while the regulatory effects of GA₃ were negligible. Functional validation under Cd exposure suggests a model wherein HMA3 and Nramp5 act in a complementary manner to sequester and redistribute Cd in leaves, thereby supporting hyperaccumulation. These findings highlight hormone-specific ROS pathways as central to transporter regulation and provide mechanistic insights to improve phytoremediation efficiency. Full article

Fusarium oxysporum is the causal agent of Fusarium dry rot disease (FDR), which results in postharvest potato losses. Biological control agents (BCAs) and phytohormone melatonin have antifungal effects on fungal pathogens and can be used as alternatives to synthetic chemical fungicides. The aim of the study was to evaluate the integrated effects of melatonin (MEL) and Bacillus amyloliquefaciens (Bamy) on the postharvest quality of potato tubers. Bamy was integrated with six MEL concentrations and screened against F. oxysporum in vitro and in vivo. The effects of the best performing treatment were evaluated for antioxidant activity, phenolic content, ascorbic acid content, and protein content on potato tubers. In the in vitro screening trial, treatment with Bamy + MEL100 had the highest mycelial growth inhibition percentage (59.92%), followed by Bamy + MEL15 and Bamy + MEL50 (56.12% and 55.27%, respectively). Potato tubers treated with Bamy + MEL100 had the lowest disease severity of FDR (50.61%) and a pathogen penetration value of 6.39 mm. Bamy + MEL50 showed a disease severity percentage of 59.72%. The exogenous application of melatonin at a concentration of 100 µM combined with B. amyloliquefaciens was the most effective treatment with the highest phenolic content (144.1 mg GAE/g DW) and protein content (68 mg/g DM) compared to the untreated tubers (104.4 GAE/g DW phenolic content and 50.06 mg/g DM protein content). Tubers treated with melatonin had the highest ascorbic acid content (5.48 mg AAE/100g DM) compared to the untreated tubers (4.09 mg AAE/100 g DM). Overall, tubers treated with a combination of melatonin and B. amyloliquefaciens showed less severe symptoms of FDR across all concentrations. Based on these findings, it can be concluded that B. amyloliquefaciens and melatonin at 100 µM concentration can be used in combination to inhibit the growth of F. oxysporum. Full article

Background: Abscisic acid (ABA), a phytohormone widely distributed in nature, has recently emerged as an endogenous regulator of glucose homeostasis in humans. Specifically, scientific studies have demonstrated that exogenous ABA supplementation improves glycemic control and reduces insulin requirements, with significant advantages in prediabetic subjects. Beyond its metabolic role, growing evidence suggests that ABA is also involved in immune responses, including those associated with pulmonary diseases. Despite these promising results, the evaluation of plasma ABA levels remains largely unexplored in clinical practice. Methods: This study aimed to evaluate whether plasma ABA concentrations differ among healthy individuals, patients with type 2 diabetes, and smokers, in order to clarify the role of ABA as a potential biomarker of both metabolic imbalance and smoking-related inflammatory stress. Results: Our findings show that ABA levels were significantly higher in healthy subjects (10.9 ± 3.8 ng/mL) compared to diabetic patients (6.8 ± 4.2 ng/mL, p < 0.01 vs. healthy subjects), with the lowest levels observed in smokers (3.5 ± 2.5 ng/mL, p < 0.0001 vs. healthy subjects and p < 0.0001 vs. diabetic patients). Moreover, a significant correlation was observed between ABA plasma concentration and number of cigarettes smoked (R² = −0.6776, p = 0.0001). Conclusions: Overall, these results highlight the relevance of measuring ABA plasma levels in both metabolic and inflammatory conditions, confirming its role as a biomarker for identifying individuals who can benefit from exogenous supplementation. 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

Gibberellins (GAs) are essential phytohormones that regulate seed dormancy release and germination. Lomatogonium rotatum (L.) Fries ex Nym is a traditional medicinal plant whose seed germination is often hindered by physiological dormancy. In this study, we systematically investigated the effects of exogenous GA₃ on the seed germination of L. rotatum and elucidated the underlying molecular regulatory mechanisms via transcriptomic analysis. GA₃ treatment (500 mg/L for 24 h) significantly improved the germination rate, vigor index, and other germination traits. RNA-seq analysis identified time-dependent transcriptional changes in GA₃-treated seeds across three developmental stages (24 h, 72 h, and 96 h). KEGG enrichment and K-means clustering revealed dynamic actiSvation of hormonal signaling, secondary metabolism, and DNA replication pathways. WGCNA uncovered two hormone-responsive co-expression modules (Red and Lightcyan) corresponding to early and late stages of germination, respectively. Key genes related to ABA and GA biosynthesis and signal transduction showed phase-specific expression, highlighting the coordinated hormonal regulation during seed germination. Our findings provide new insights into the molecular basis of GA₃-regulated seed germination and offer theoretical support for the cultivation and utilization of L. rotatum. Full article

Anthocyanins are important phenolic compounds in grape skins, affecting the color, oxidation resistance, and aging ability of red wine. In recent years, global warming has had a negative effect on anthocyanin biosynthesis in grape berries. Ethylene serves as a crucial phytohormone regulating the development and ripening processes of fruit; however, the specific molecular mechanism and the regulatory network between ethylene signaling and the anthocyanin biosynthesis pathway remain incompletely understood. In this study, 400 mg/L ethephon (ETH) solution was sprayed onto the surface of grape berries at the lag phase (EL-34), and the changes in anthocyanin-related genes and metabolites were explored through transcriptomic and metabolomic analysis. The results showed that ETH treatment increased Brix and pH in mature berries. In total, 35 individual anthocyanins were detected, in which 21 individual anthocyanins were enhanced by ETH treatment. However, the anthocyanin profile was not affected by exogenous ethylene. Transcriptomics analysis showed that there were a total of 825 and 1399 differentially expressed genes (DEGs) 12 h and 24 h after treatment. Moreover, key structural genes in the anthocyanin synthesis pathway were strongly induced, including VvPAL, VvCHS, VvF3H, VvF3′5′H, VvDFR and VvUFGT. At the maturity stage (EL-38), the expression levels of these genes were still higher in EHT-treated berries than in the control. ETH treatment also influenced the expression of genes related to hormone biosynthesis and signal transduction. The ethylene biosynthesis gene (VvACO), ethylene receptor genes (VvETR2, VvERS1 and VvEIN4), ABA biosynthesis gene (VvNCED2), and ABA receptor gene (VvPYL4) were up-regulated by ETH treatment, while the auxin biosynthesis gene (VvTAA3) and seven genes of the auxin-responsive protein were inhibited by exogenous ethylene. Meanwhile, ETH treatment promoted the expression of the sugar transporter gene (VvEDL16) and two sucrose synthase genes (VvSUS2 and VvSUS6). In EHT-treated berries, 19 MYB and 23 ERF genes were expressed differently compared with the control (p < 0.05). This study provides the theoretical foundation and technical support for the regulation of anthocyanin synthesis in non-climacteric fruit. Full article

Humulus lupulus L. (hop) is a multipurpose crop valued for its essential role in beer production and for its bioactive compounds with recognized medicinal properties. Otherwise, climate change represents a major challenge to agriculture, particularly impacting the cultivation of crops with stenoecious characteristics, such as hop. This highlights the urgent need to enhance crop resilience to adverse environmental conditions. The phytohormone abscisic acid (ABA) is a key regulator of plant responses to abiotic stress, yet the ABA signaling pathway remains poorly characterized in hop. Harnessing the publicly available hop genomics resources, we identified eight members of the PYRABACTIN RESISTANCE 1 LIKE ABA receptor family (HlPYLs). Phylogenetic and gene structure analyses classified these HlPYLs into the three canonical ABA receptor subfamilies. Furthermore, all eight HlPYLs are likely functional, as suggested by the protein sequence visual analysis. Expression profiling indicates that ABA perception in hop is primarily mediated by the HlPYL1-like and HlPYL8-like subfamilies, while the HlPYL4-like group appears to play a more limited role. Structure modeling and topology predictions of HlPYL1b and HlPYL2 provided insights into their potential functional mechanisms. To assess the physiological relevance of ABA signaling in hop, we evaluated the impact of exogenous ABA application during the ex vitro acclimatization phase. ABA-treated plants exhibited more robust growth, reduced stress symptoms, and improved acclimatization success. These effects were associated with reduced leaf transpiration and enhanced stomatal closure, consistent with ABA-mediated drought tolerance mechanisms. Altogether, this study provides the first comprehensive characterization of ABA receptor components in hop and demonstrates the practical utility of ABA in improving plant performance under ex vitro conditions. These findings lay the groundwork for further functional studies and highlight ABA signaling as a promising target for enhancing stress resilience in hop, with broader implications for sustainable agriculture in the face of climate change. Full article

Sinomenium acutum is the main raw material for sinomenine. Empirical evidence indicates a marked disparity in sinomenine content among S. acutum plants with different genders, resulting in varying medicinal potential of the processing products. However, the mechanism underlying gender-determined differences in sinomenine accumulation is still elusive. In this study, untargeted metabolomics was performed among female, male, and undifferentiated S. acutum plants. In total, 1213 metabolites were identified, and most of them vary in the roots but not in the leaves among the different genders. Integrated correlation analysis on the DAMs (differentially accumulated metabolites) enriched in the isoquinoline alkaloid biosynthesis pathway suggests coclaurine as an intermediate determining gender-dependent sinomenine variation. Furthermore, hormonal profiling revealed 34 endogenous phytohormones exhibiting significant gender-based discrepancy in the roots. Among these, ABA (abscisic acid) and 5-DS (5-deoxystrigol) show significant positive correlation with sinomenine content. Then, exogenous ABA with gradient concentration was applied on S. acutum plants, and the sinomenine content in the roots increased from 31% to 166% under treatment. Our findings demonstrate that coclaurine might serve as a pivotal intermediate during sinomenine biosynthesis in S. acutum. Meanwhile, it is speculated that ABA is a key factor regulating different sinomenine accumulation, which provide a potential method to improve the yield of sinomenine. Full article