Chlorophyll Metabolism Research Articles

Protective mechanisms of exogenous melatonin on chlorophyll metabolism and photosynthesis in tomato seedlings under heat stress

Elevated temperatures severely affect plant growth, reducing yield and quality. Melatonin (MT), a plant biomolecule, is known to enhance stress tolerance, but its role in heat resistance and underlying mechanisms require further exploration. This study investigates MT’s regulatory effects on chlorophyll metabolism and photosynthesis in tomato seedlings under high-temperature stress (40°C). Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress. MT application increased osmolytes (proline and soluble sugar), enhanced antioxidant enzyme activities [catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX)], and reduced oxidative damage markers (H2O2, O2−, malondialdehyde, and conductivity). Photosynthetic parameters, including key enzyme activities [sedoheptulose-1,7-bisphosphatase (SBPase), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH)], photochemical efficiency [Fv/Fm and Y(II)], and photochemical quenching (Qp), were significantly improved, restoring the OJIP curve and enhancing photosynthesis. MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b, 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels] and upregulating synthesis genes (SlHEMA1, SlPORB, SlPORC, and SlCHLI) while inhibiting degradation genes (SlCLH1, SlCLH2, SlPAO, SlPPH, and SlRCCR). These findings demonstrate that MT enhances tomato heat tolerance by protecting chlorophyll metabolism and photosynthesis, offering a theoretical basis for improving crop resilience to heat stress.

The MADS-Box Transcription Factor CaRIN Positively Regulates Chlorophyll Degradation During Pepper (Capsicum annuum L.) Fruit Ripening by Repressing the Expression of CaLhcb-P4

Pepper (Capsicum spp.) is an important global vegetable and spice, with fruit color being a key determinant of its commercial quality. However, the regulatory mechanisms underlying pepper fruit color are still not fully understood. This study focuses on the MADS-RIPENING INHIBITOR (MADS-RIN), a MADS-box transcription factor that regulates various aspects of fruit ripening, including pigmentation. We identified CaRIN, a homolog of tomato’s SlRIN, whose expression is closely associated with fruit ripening in pepper. Silencing CaRIN through virus-induced gene silencing (VIGS) resulted in increased chlorophyll and chlorophyll a content, reduced carotenoid accumulation, and uneven fruit coloration. Integrative analysis of the RNA-seq and DAP-seq data identified 77 target genes regulated by CaRIN, which was involved in processes such as chlorophyll metabolism and plant hormone signaling. Yeast one-hybrid (Y1H) and dual-luciferase (LUC) assays demonstrated that CaRIN directly bound to the promoter of CaLhcb-P4, repressing its expression. Downregulation of CaLhcb-P4 in pepper fruits via VIGS accelerated chlorophyll degradation. Additionally, CaRIN indirectly regulated multiple genes associated with chlorophyll and carotenoid metabolism, sugar transport, and cell wall degradation. These findings provide novel insights into the regulatory mechanisms of chlorophyll degradation during pepper fruit ripening, offering a foundation for further research and potential genetic improvement strategies.

Investigation into the mechanisms of photosynthetic regulation and adaptation under salt stress in lavender.

Salinity stress is a major threat to agricultural productivity and sustainability, often causing irreversible damage to photosynthesis. Lavender, a valuable aromatic plant, experiences growth impacts under salt stress. However, the regulatory mechanisms of photosynthesis related to its adaptation to salt stress remain unclear. In this study, lavender was exposed to 0, 100, 200, and 300mM NaCl for 28 days. It was observed that lavender effectively maintained chlorophyll stability when salt concentrations were below 200mM and stress duration was under 21 days. The most effective model for lavender under salt stress was identified as a right-angled hyperbolic modified model. Under moderate salt stress (100mM, 200mM), genes such as LaPSB28, LaPSBS, and LaPSBR contributed to PSII core stability, enhanced photosynthetic pigment levels, and sustained high electron transfer rates to improve salt-tolerance. Additionally, LaLHCB4-1 and LaPSAK-1 regulated stomatal size, thereby facilitating gas exchange and supporting the photosynthetic process. Conversely, under high salt stress (300mM), LaPSBW-1, -2, and LaPSAB were found to reduce photosynthetic pigment levels and inhibit photosynthetic activity. However, genes such as LaCHLG-2, LaGLG-3, LaBAM1-1 and -3, and LaCHLP-3 aided in starch synthesis by increasing pigment content, thus promoting energy balance and enhancing salt tolerance. This regulation involved photosynthesis-antenna proteins and pathways related to starch, sucrose, and chlorophyll metabolism. These findings may support the cultivation of salt-tolerant lavender varieties and maximize saline soil usage.

Molecular investigation of how drought stress affects chlorophyll metabolism and photosynthesis in leaves of C3 and C4 plant species: A transcriptome meta-analysis

Molecular investigation of how drought stress affects chlorophyll metabolism and photosynthesis in leaves of C3 and C4 plant species: A transcriptome meta-analysis

Decoding the Intricate Metabolic and Biochemical Changes in Plant Senescence: a focus on chloroplasts and mitochondria.

Plant senescence is a genetically controlled process that results in the programmed death of plant cells, organs, or the entire plant. This process is essential for nutrient recycling and supports the production of plant offspring. Environmental stresses such as drought and heat can hasten senescence, reducing photosynthetic efficiency and significantly affecting crop quality and yield. This mini-review seeks to clarify the complex metabolic and biochemical transformations involved in plant senescence by explaining the mechanisms in a straightforward and connected manner. It focuses on key cellular processes such as genetically programmed or stress-induced senescence, chlorophyll metabolism and nutrient recycling, while also exploring the roles of signaling molecules and pathways. Understanding the complexities of plant senescence may help manage crop aging, address climate change, and cut post-harvest losses. Enhancing crop resilience to stress and decelerating aging can reduce the need for overproduction, thereby decreasing pollution and conserving resources. Tackling food waste, which constitutes about one-third of global supplies, is crucial for ensuring food security and fostering environmental sustainability.

Molecular docking and differential rbcl gene expression reveal variation in glyphosate herbicide tolerance of sugarcane varieties.

Glyphosate is an extensively employed herbicide in agriculture, specifically for sugarcane cultivation. The situation is different with the extensive physiological and genetic effects exerted by this herbicide on a range of plant species, including sugarcane, whose model basis is still poorly characterized, although its primary mode of action, which acts on the EPSPS enzyme in the shikimic acid pathway, is completely elucidated. The current study was aimed at investigating the stability of glyphosate formulation, molecular interactions of glyphosate formulation with rbcL enzyme associated with chlorophyll metabolism, and its effects on varieties of sugarcane. The stability of a ground-up glyphosate formulation was assessed under accelerated storage conditions. Molecular docking was performed to analyze interactions between glyphosate derivatives and rbcL. Two sugarcane varieties (G84-47 and GT54-9) were treated with increasing glyphosate concentrations (0.2, 0.4, and 0.8 mg L-1) to evaluate effects on chlorophyll content, plant height, herbicide tolerance, and rbcL expression. The formulation showed good stability with minor degradation (47.55-47.14%). N-Nitrosoglyphosate and 2-(phosphonomethylamino)acetic acid exhibited favorable binding affinities with rbcL. Glyphosate treatment reduced chlorophyll content and plant height dose-dependently, with G84-47 showing higher sensitivity. GT54-9 demonstrated higher herbicide tolerance in survival analysis. rbcL expression remained stable in G84-47 but was significantly upregulated in GT54-9 under high herbicide stress. This study reveals genetic variability in sugarcane responses to glyphosate, with variety-specific mechanisms underlying stress adaptation. The inducible rbcL expression in tolerant varieties provides insights into herbicide resistance mechanisms. These findings can inform marker-assisted breeding and improve agronomic practices for enhanced sugarcane cultivation resilience and sustainability.

26S Proteasome Subunit SlPBB2 Regulates Fruit Development and Ripening in Tomato.

Proteasomes are protein complexes responsible for degrading unneeded or damaged proteins through proteolysis and play critical roles in regulating plant development and response to environmental stresses. However, it is still unclear whether proteasomes regulate fruit development and ripening. In this study, we investigated the function of a core proteasome subunit, SlPBB2, in tomato fruit. We found that silencing the SlPPB2 gene through virus-induced gene silencing resulted in tomato seedling death, while SlPPB2 RNA interference (RNAi-SlPBB2) plants driven by a fruit-specific promoter PP2C present normal development. Further observation reveals that silencing SlPBB2 in fruits impaired the chloroplast development and chlorophyll metabolism of fruits, increased the fruit size, and delayed fruit ripening. These findings provide novel insights into the role of proteasomes in regulating fruit development and ripening.

The BES1/BZR1 transcriptional factor SlBES2 regulates photosynthetic apparatus in tomato fruit

BackgroundFruit photosynthetic apparatus development comprises a series of biological processes which is essential in determining fruit development and quality formation. However, the understanding of the regulation of fruit photosynthetic apparatus development remains poor.ResultsIn this study, we identified a transcriptional factor SlBES2, the closest homolog of BES1 and BZR1 in tomato BES1 family, is highly expressed in fruit at mature green (MG) stage and exhibited transcriptional inhibition activity. Down-regulation of SlBES2 resulted in fruits showing paler fruit than wild type at MG stage, in contrast, SlBES2-overexpressing tomato lines bore deeper green fruits. Notably, chlorophyll content and number of thylakoids per chloroplast in fruit was substantially increased in SlBES2-overexpressing lines, while markedly decreased in SlBES2-suppressing lines. Comparative transcriptome analysis revealed that multiple genes of the photosystem, chloroplast development and chlorophyll metabolism pathways were regulated by SlBES2. Further verification revealed that SlBES2 can significantly repress the transcriptional activity of SlNYC1 and Green-Flesh, and physically interact with protein SlHY5.ConclusionsCollectively, this study demonstrated that SlBES2 plays an important role in regulating fruit photosynthetic apparatus development through either transcriptional repression of genes involved in chlorophyll breakdown, or posttranscriptional regulation of proteins associated with plant photomorphogenesis and chloroplast development. Our findings add a new actor to the complex mechanisms underlying photosynthetic apparatus during fruit development.

Molecular and Biochemical Mechanisms of Scutellum Color Variation in Bactrocera dorsalis Adults (Diptera: Tephritidae).

Bactrocera dorsalis (Hendel) is an invasive fruit and vegetable pest, infesting citrus, mango, carambola, etc. We observed that the posterior thoracic scutella of some B. dorsalis adults are yellow, some light yellow, and some white in China. Compared with the B. dorsalis races with a yellow scutellum (YS) and white scutellum (WS), the race with a light-yellow scutellum (LYS) is dominant in citrus and carambola orchards. To reveal genetic correlates among the three races, the genomes of 22 samples (8 with YS, 7 with LYS, and 7 with WS) were sequenced by high-throughput sequencing technology. Single-nucleotide polymorphism (SNP) annotation showed that there were 17,580 non-synonymous mutation sites located in the exonic region. Principal component analysis based on independent SNP data revealed that the SNPs with LYS were more similar to that with YS when compared with WS. Most genes associated with scutellum color variation were involved in three pathways: oxidative phosphorylation, porphyrin and chlorophyll metabolism, and terpenoid backbone biosynthesis. By comparing the sequences among the three races, we screened out 276 differential genes (DGs) in YS vs. WS, 185 DGs in LYS vs. WS, and 104 DGs in YS vs. LYS. Most genes determining color variation in B. dorsalis scutella were located on chromosomes 2-5. Biochemical analysis showed that β-carotene content in YS and LYS was significantly higher than that in WS at any stage of adult days 1, 10, and 20. No significant differences were observed in cytochrome P450 or melanin content in YS, LYS, or WS. Our study provides results on aspects of scutellum color variation in B. dorsalis adults, providing molecular and physiological information for revealing the adaptation and evolution of the B. dorsalis population.

Methyl Jasmonate Was Involved in Hydrogen Sulfide-Alleviated Cadmium Stress in Cucumber Plants Through ROS Homeostasis and Chlorophyll Metabolism.

Cadmium (Cd), as one of the most toxic nonessential elements, severely prohibits plant growth and development. Hydrogen sulfide (H2S) and methyl jasmonate (MeJA) play essential roles in plant response to abiotic stress. However, the potential mechanism of H2S and MeJA in alleviating Cd stress in plants remains unclear. In the current study, the importance and crosstalk of H2S and MeJA in the Cd tolerance of cucumber seedlings have been investigated. Our results revealed that Cd stress obviously prohibited the growth of cucumber seedlings. Optimal concentrations of H2S donor sodium hydrosulfide (NaHS) or MeJA treatment, respectively, or in combination, significantly enhanced seedling growth under Cd stress. However, the positive effects of H2S during seedling growth were obviously reversed by the application of MeJA biosynthesis inhibitors, which implied that MeJA might be involved in the H2S-improved growth of cucumber seedlings under Cd stress. Moreover, Cd stress resulted in the increase in hydrogen peroxide (H2O2), superoxide radical (O2·-) accumulation, and impaired the functioning of the ascorbate-glutathione cycle. Both H2S and MeJA decreased the reactive oxygen species (ROS) level and ameliorated the negative effects of Cd stress through significantly increasing the ratio of ascorbate (AsA)/dehydroascorbic acid (DHA) and reduced glutathione (GSH)/oxidized glutathione (GSSG). Besides that, the expression level of ROS scavenge genes was significantly upregulated by the application of exogenous H2S or MeJA treatment. Moreover, H2S and MeJA significantly enhanced the chlorophyll concentration and inhibited chlorophyll degradation through decreasing the expression levels of chlorophyll catabolic enzymes. Additionally, exogenous H2S and MeJA obviously enhanced the chlorophyll fluorescence. However, MeJA biosynthesis inhibitors significantly suppressed the positive role of H2S. The above results suggested MeJA is involved in H2S-induced Cd stress alleviation in cucumber seedlings through enhancing ROS-scavenge capacity and improving the photosynthesis system.

Polystyrene Microplastics Induce Photosynthetic Impairment in Navicula sp. at Physiological and Transcriptomic Levels

The rising concentration of microplastics (MPs) in aquatic environments poses increasing ecological risks, yet their impacts on biological communities remain largely unrevealed. This study investigated how aminopolystyrene microplastics (PS-NH2) affect physiology and gene expression using the freshwater alga Navicula sp. as the test species. After exposing Navicula sp. to high PS-NH2 concentrations for 24 h, growth was inhibited, with the most significant effect seen after 48 h. Increasing PS-NH2 concentrations reduced chlorophyll content, maximum photochemical quantum yield (Fv/Fm), and the photochemical quenching coefficient (Qp), while the non-photochemical quenching coefficient (NPQ) increased, indicating a substantial impact on photosynthesis. PS-NH2 exposure, damaged cell membrane microstructures, activated antioxidant enzymes, and significantly increased malondialdehyde (MDA), glutathione peroxidase (GPX), and superoxide dismutase (SOD) activities. Transcriptomic analysis revealed that PS-NH2 also affected the gene expression of Navicula sp. The differentially expressed genes (DEGs) are mainly related to porphyrin and chlorophyll metabolism, carbon fixation in photosynthesis, endocytosis, and glycolysis/gluconeogenesis. Protein–protein interaction (PPI) analysis revealed significant interactions among DEGs, particularly within photosystem II. These findings shed insights into the toxic mechanisms and environmental implications of microplastic interactions with phytoplankton, deepening our understanding of the potential adverse effects of microplastics in aquatic ecosystems.

The mechanism of arsenic trioxide and microwave ablation in the treatment of oral squamous cell carcinoma based on high throughput sequencing

AbstractOral squamous cell carcinoma (OSCC) is a common head and neck malignant tumour with high incidence and poor prognosis. Arsenic trioxide (ATO) has therapeutic effects on solid tumours. Microwave ablation (MWA) has unique advantages in the treatment of solid tumours. However, the therapeutic mechanism of ATO and MWA, as well as their combined effect on OSCC were largely unelucidated. Cal‐27 cell‐bearing nude mice were treated with ATO and/or MWA, respectively. RNA sequencing was used to obtain gene expression profiles in tumour tissues of mice treated by ATO or MWA. RNA sequencing results were verified by real‐time polymerase chain reaction (PCR). The lncRNA‐miRNA‐mRNA co‐expression network was constructed based on the competitive endogenous RNA (ceRNA) theory. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed using differentially expressed genes. The combined effect of ATO and MWA on OSCC was evaluated. Finally, CCK‐8 assay, EdU assay and transwell migration assay were performed to detect the effect of HSPA6 on the proliferation and migration of OSCC cells. The reduced volume of tumour tissues was observed in both ATO‐ and MWA‐treated groups. 37.8% decreased in the ATO group and 35.0% in the MWA group. A total of 207 and 539 differentially expressed mRNAs and lncRNAs were identified in the ATO group. And a total of 200 and 522 differentially expressed mRNAs and lncRNAs in the MWA group were identified. The expression levels of 8 genes were verified by real‐time PCR. The differentially expressed genes were closely related to “chemical carcinogenesis”, “herpes simplex infection”, “porphyrin and chlorophyll metabolism”, and “MAPK signalling pathway”. The lncRNA‐miRNA‐mRNA co‐expression networks were constructed. The combined treatment with ATO and MWA showed a better inhibitive effect on OSCC than either of them. The synergistic effect of ATO and MWA was related to the upregulation of HSPA6. The downregulation of HSPA6 could promote the proliferation and migration of OSCC cells. This study detected the long non‐coding RNA and mRNA expression profiles related to the treatment of OSCC and constructed corresponding ceRNA networks. Arsenic trioxide and MWA have a synergistic effect on OSCC, which was related to the upregulation of HSPA6.

Comprehensive physiological, transcriptomic, and metabolomic analyses revealed the regulation mechanism of evergreen and cold resistance of Pinus koraiensis needles

As a significant fruit and timber tree species among conifers, Pinus koraiensis remains it evergreen status throughout the harsh winters of the north, a testament to its intricate and prolonged evolutionary adaptation. This study delves into the annual trends of physiological indicators, gene expression levels, and metabolite accumulation to dissect the seasonal adaptability of P. koraiensis needles. Chlorophyll content reaches its zenith primarily between July and September, whereas carotenoids persist until spring. Additionally, notable seasonal variations are observed in the levels of soluble sugar and protein. Transcriptome data is categorized into four distinct stages: spring (S2), summer (S3-S4), autumn (S5), and winter (S6-S1). The differential expression of transcription factor genes, including bHLH, MYB-related, AP2/ERF, C3H, and NAC, provides insights into the needles’ seasonal adaptations. Analysis of chlorophyll and carotenoid metabolism, sugar metabolism, and the MAPK signaling pathway identifies PSY5 (Cluster-50735.3), AMY13 (Cluster-37114.0), pgm1 (Cluster-46022.0), and MEKK1-1 (Cluster-33069.0) may as potential key genes involved in sustaining the needle’s evergreen nature and cold resistance. Ultimately, a comprehensive annual adaptability map for P. koraiensis is proposed, enhancing understanding of its responses to seasonal variations.

Combined application of rutin and silicon sustains maize seedlings osmotic stress tolerance by improving photosynthetic capacity and chlorophyll metabolism

In the current study, the role of external applications of rutin (Rut) and silicon (Si) in stress tolerance was investigated. Although it is known that Si has a role in improving plant defense against a variety of stresses, the role of Rut application in stress response remains unclear. Therefore, the current study was designed to evaluate the function of the synergistic effect of combined Rut and Si applications on the photosynthetic capacity of maize seedlings under osmotic stress. Twenty-one-day-old seedlings were treated with Rut (60 mg L-1) and Si (1 mM), and exposed to osmotic stress (induced by 10% and 15% (w/v) polyethylene glycol) for 48 h. The individual application of Rut and Si and especially the simultaneous treatment of Rut+Si improved the gas exchange parameters, chlorophyll content, photosystem II (PSII) activity, Rubisco enzyme activity, and the expression levels of magnesium chelatase and Rubisco genes, but decreased the expression of chlorophyllase gene under osmotic stress in comparison to osmotic stress alone. These findings suggest that exogenous Rut and Si can improve photosynthetic capacity in maize seedlings exposed to osmotic stress by increasing PSII activity and the expression of genes involved in photosynthesis and chlorophyll metabolism, as well as reducing chlorophyll degradation. The simultaneous treatment of Rut+Si may be useful in developing osmotic stress tolerance of plants.

The BCM1-EGY1 module balances chlorophyll biosynthesis and breakdown to confer chlorophyll homeostasis in land plants

Chlorophyll metabolism has evolved during plant evolution. The strictly light-dependent nature of chlorophyll biosynthesis found in angiosperms requires tight coordination of chlorophyll biosynthesis and breakdown to achieve chlorophyll homeostasis. However, the specific control mechanism is still unknown. Here, we demonstrate that the scaffold protein BALANCE OF CHLOROPHYLL METABOLISM1 (BCM1) has co-evolved with the carboxy-terminal domains of specific enzymes involved in chlorophyll biosynthesis and breakdown, including GENOMES UNCOUPLED 4 (GUN4) and Mg-dechelatase 1 (SGR1). We found that the land-plant-specific interaction of BCM1 with the carboxy-terminal domains of GUN4 and SGR1 is indispensable for the concurrent stimulation of chlorophyll biosynthesis and suppression of chlorophyll breakdown. The land plant-specific carboxy-terminal domain is essential for the membrane docking and turnover of GUN4, whereas it is key for proteolysis of SGR1. More importantly, we identified the metallopeptidase Gravitropism-deficient and Yellow-green 1 (EGY1) as the proteolytic machinery responsible for BCM1-mediated proteolysis of SGR1. In summary, this study reveals the BCM1-EGY1 module has evolved to maintain chlorophyll homeostasis by the post-translational control of the balance between chlorophyll biosynthesis and breakdown. This mechanism thus represents an evolutionary response to the metabolic demands imposed on plants in terrestrial environments.

Mechanism of Bacillus cooperating with silicon to re-balance chlorophyll metabolism and restore carbon metabolism of Glycyrrhiza uralensis Fisch. Seedlings exposed to salt-drought stress

Salt-drought is a major environmental event affecting crop productivity and quality by causing chlorophyll (Chl) and carbon balance disorder. There has been growing interest in the application of endophyte and silicon (Si), as inoculants for saline and drought land restoration. This study investigates the impact of Bacillus (Bs), Si, and Bs + Si on the disorder of Chl metabolism and carbon balance of G. uralensis seedlings under salt-drought stress (SD). Results showed that both Bs and Si treatments enhanced Chl and carbon metabolism, with the combined Bs and Si treatment showing a synergistic effect. Specifically, Bs + Si enhanced the mutual conversion of Chl a and Chl b, restored the equilibrium in Chl a and Chl b content, and increased RuBisco activity by 31.07%, thereby promoting carbon fixation. Subsequently, Bs + Si re-balanced the carbohydrate content, by increasing the sucrose synthase (SS), and β-amylase (BMY) activities by 49.57%, and 83.59% respectively, and decreasing sucrose phosphate synthase (SPS), and granule-bound starch synthase (GBSS) activities by 38.93%, 40.93% respectively etc involved in the metabolism of sucrose and starch. Furthermore, Bs + Si facilitated the restoration of the typical progression of the tricarboxylic acid (TCA) cycle and glycolysis pathway (EMP). These findings highlight the synergistic role of Bs and Si in enhancing the salt and drought resilience of G. uralensis seedlings, offering promising strategies for sustainable agriculture, improving crop resilience to climate change, and achieving the “dual carbon” goals of carbon peaking and carbon neutrality.

Time-series metabolomic analysis revealed altered metabolism of cynomolgus monkeys after injecting exosomes.

Recent years, exosomes have been increasing used to treat diseases, but there is little research on how exosomes affect the metabolism of the body after entering. Therefore, in this study, we discussed the changes of metabolic spectrum and determined the differentially expressed metabolites in the serum of cynomolgus monkeys after injecting exosomes. Six cynomolgus monkeys were divided into control group and exosomes group. After intravenous injection of exosomes, the peripheral blood serum of cynomolgus monkeys was collected at baseline, day 1, day 7 and day 14 respectively. An ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based non-targeted metabolomics platform was used to detect the metabolites. The metabolic spectra of two groups of cynomolgus monkeys were identified and compared, and the time series changes of metabolites in exosomes were described. The results showed that there was significant difference in metabolic spectrum between the two groups. 45, 114, 49, 39 differentially expressed metabolites were identified in baseline, day 1, day 7, and day 14, respectively. 6-hydroxydopamine, a metabolite related to the regulation of nerve function, was also found. Tryptophan metabolism, choline metabolism in cancer, porphyrin and chlorophyll metabolism were involved in day 1. Sphingolipid metabolism and histidine metabolism were involved in day 7. Three pathways, including choline metabolism, sphingolipid metabolism and biotin metabolism in cancer were involved in day 14. Through time series analysis, it was found that the level of propionylcarnitine and biliverdin increased on day 1 after inoculation with exosomes, while the level of hippuric acid decreased. These changes of immune-related metabolites suggested that exosomes might participate in the immunoregulation reaction after entering the body of cynomolgus monkeys. In our current study, we found that exosomes injected intravenously affect the changes of metabolites and metabolic pathways in cynomolgus monkeys. Intravenous injection of exosomes may affect the metabolite 6-hydroxydopamine, sphingolipid metabolic pathway, and choline metabolic in cancer pathway, which is of some significance for the treatment of Parkinson's disease. In addition, exosomes may also affect the immune-related metabolites in vivo, such as propionylcarnitine, biliverdin, hippuric acid metabolites, as well as tryptophan metabolism pathway, sphingolipid metabolism pathway involved in immune regulation, which is of great significance for the future study of immune-regulatory mechanisms of exosomes.

Comparative transcriptome and metabolomic analysis reveal key genes and mechanisms responsible for the dark-green leaf color of a strawberry mutant

Photosynthesis is a source of energy for various types of plant life activities and is essential for plant growth and development. Consequently, the study of photosynthetic mechanisms has been a hot spot. Leaf color mutants has always been ideal materials for exploring the mechanisms of chlorophyll metabolism and photosynthesis. In this study, we identified a leaf color mutant of ‘Benihoppe’ strawberry in the field, which exhibited a darker green leaf color compared with the wild type. The content of total chlorophyll and carotenoid in the mutant leaves was elevated by 7.44–20.23% and 8.9–21.92%, respectively, compared with that of the wild type. Additionally, net photosynthetic rate in the mutant increased by 20.13%. Further transcriptome analysis showed that significant upregulation of genes such as GLK1, PPR, and MORF9 in the mutant leaves, which promoted chloroplast development. The expression levels of UROD, PPOC, PORA, CHLG, and CPOX were significantly upregulated during chlorophyll synthesis, while the expression levels of HCAR and CYP89A9 were significantly downregulated during chlorophyll degradation, thus leading to the accumulation of chlorophyll in mutant leaves. The upregulation of gene expression levels such as PetM, AtpD, PGK, and RPI4 during photosynthesis promoted multiple stages of light and dark reaction, thereby enhancing the photosynthetic capacity of the mutant. And the changes in metabolites such as monogalactosyl monoacylglycerol (MGMG), glucuronosyldiacylglycerol (GlcADG), raffinose, etc. also indicate that the mutant has metabolic differences in chloroplast composition and photosynthesis compared to ‘Benihoppe’. The above results not only deepen our understanding of the mechanism behind the dark-green leaf color in strawberry mutants but also provide potential genetic resources for cultivating strawberry varieties with enhanced photosynthetic capacity.

Effects of exogenous melatonin on drought stress in celery (Apium graveolens L.): unraveling the modulation of chlorophyll and glucose metabolism pathways

Drought, a prevalent abiotic stressor, significantly impacts plant yield and quality. Melatonin (MT), a potent and economical growth regulator, plays a pivotal role in augmenting crop resilience against stress. This study investigated the efficacy of exogenous MT on drought-stressed celery seedlings by comprehensively analyzing phenotypic, physiological, and molecular attributes. The results revealed that exogenous MT mitigated celery seedling damage under drought stress, lowered malondialdehyde (MDA) concentrations, elevated oxidase activities, osmolyte levels, chlorophyll content, and augmented light energy conversion efficiency. Transcriptomic analysis demonstrated that MT could regulate chlorophyll synthesis genes (AgPORA1 and AgDVR2), contributing to heightened photosynthetic potential and increased drought tolerance in celery. Moreover, MT was found to modulate glycolytic pathways, upregulate pyruvate synthesis genes (AgPEP1 and AgPK3), and downregulate degradation genes (AgPDC2 and AgPDHA2), thereby promoting pyruvate accumulation and enhancing peroxidase activity and drought tolerance. The RNA-seq and qRT-PCR analyses demonstrated similar results, showing the same general expression trends. The study elucidates the physiological and molecular mechanisms underlying MT’s stress-alleviating effects in celery seedlings, offering insights into MT-based strategies in plant cultivation and breeding for arid environments.

Based on Serum Pharmacochemistry and Metabolomics Studied the Pharmacodynamic Material Basis and Mechanism of Rubi Fructus (Fupenzi) in Improving the Symptom of Kidney-Yang Deficiency.

Rubi fructus (Fupenzi) is the immature fruit of East China Rubi fructus, which is widely used in medicine, food, health food and other fields. Since ancient times, Fupenzi has been considered to be an important medicine for tonifying the kidney in terms of nourishing the liver and kidney, fixing essence and reducing urine, but its effective components and mechanism are not clear. In this paper, the effective components of Rubi fructus were analyzed by detecting the components of Fupenzi in vivo and in vitro. Adenine was used to replicate the model of kidney yang deficiency, and organ index, biochemical index and histopathology were used to evaluate the effect of different doses of Fupenzi on tonifying kidney yang. Metabonomics technique was used to analyze the metabolic regulation mechanism of Fupenzi in improving kidney yang deficiency syndrome. The results showed that 61 chemical constituents of Fupenzi were identified in vitro, including 18 flavonoids, 19 organic acids, 5 coumarins, 8 terpenoids, 7 amino acids and 4 other components. A total of 51 chemical components were identified, including 30 prototype components and 21 metabolic components, which may be the effective components of Fupenzi. The results of pharmacodynamics showed that compared with the model group, the renal index, testicular index and epididymal index of rats in each Fupenzi group were significantly improved (p<0.01), cAMP significantly increased (p<0.05), cGMP decreased (p<0.05) and cAMP/cGMP ratio increased significantly (p<0.05). The content of ACTH in low dose group increased significantly (p<0.05), while the content of ACTH in middle and high dose groups increased, but there was no significant difference. The results of HE staining showed that compared with the model group, the kidney, testis and epididymis of rats in each treatment group were significantly improved. In general, these changes may be mainly through primary bile acid biosynthesis, linoleic acid metabolism, steroid hormone biosynthesis, β-alanine metabolism, glutathione metabolism, porphyrin and chlorophyll metabolism, unsaturated fatty acid biosynthesis, arachidonic acid metabolism, arginine and proline metabolism and other metabolic pathways to improve adenine-induced metabolic disorders in rats with kidney-yang deficiency syndrome.