CmERF1 acts as a positive regulator of fruits and leaves growth in melon (Cucumis melo L.).

Melon (Cucumis melo L.) is an important horticultural and economic crop. ETHYLENE RESPONSE FACTOR1 (ERF1) plays an important role in regulating plant development, and the resistance to multiple biotic and abiotic stresses. In this study, developmental biology, molecular biology and biochemical assays were performed to explore the biological function of CmERF1 in melon. Abundant transcripts of CmERF1 were found in ovary at green-yellow bud (GYB) and rapid enlargement (ORE) stages. In CmERF1 promoter, the cis-regulatory elements for indoleacetic acid (IAA), methyl jasmonate (MeJA), salicylic acid (SA), abscisic acid (ABA), gibberellic acid (GA), light and low temperature responses were found. CmERF1 could be significantly induced by ethylene, IAA, MeJA, SA, ABA, and respond to continuous light and low temperature stresses in melon. Ectopic expression of CmERF1 increased the length of siliqua and carpopodium, and expanded the size of leaves in Arabidopsis. Knockdown of CmERF1 led to smaller ovary at anthesis, mature fruit and leaves in melon. In CmERF1-RNAi #2 plants, 75 genes were differently expressed compared with control, and the promoter regions of 28 differential expression genes (DEGs) contained the GCC-box (AGCCGCC) or DRE (A/GCCGAC) cis-acting elements of CmERF1. A homolog of cell division cycle protein 48 (CmCDC48) was proved to be the direct target of CmERF1 by the yeast one-hybrid assay and dual-luciferase (LUC) reporter (DLR) system. These results indicated that CmERF1 was able to promote the growth of fruits and leaves, and involved in multiple hormones and environmental signaling pathways in melon.

Harbinger transposon insertion in ethylene signaling gene leads to emergence of new sexual forms in cucurbits.

In flowering plants, the predominant sexual morph is hermaphroditism, and the emergence of unisexuality is poorly understood. Using Cucumis melo (melon) as a model system, we explore the mechanisms driving sexual forms. We identify a spontaneous mutant exhibiting a transition from bisexual to unisexual male flower, and identify the causal mutation as a Harbinger transposon impairing the expression of Ethylene Insensitive 2 (CmEIN2) gene. Genetics and transcriptomic analysis reveal a dual role of CmEIN2 in both sex determination and fruit shape formation. Upon expression of CmACS11, EIN2 is recruited to repress the expression of the carpel inhibitor, CmWIP1. Subsequently, EIN2 is recruited to mediate stamina inhibition. Following the sex determination phase, EIN2 promotes fruit shape elongation. Genome-wide analysis reveals that Harbinger transposon mobilization is triggered by environmental cues, and integrates preferentially in active chromatin, particularly within promoter regions. Characterization of a large collection of melon germplasm points to active transpositions in the wild, compared to cultivated accessions. Our study underscores the association between chromatin dynamics and the temporal aspects of mobile genetic element insertions, providing valuable insights into plant adaptation and crop genome evolution.

Complete genome sequence of a novel mitovirus identified in the phytopathogenic fungus Fusarium oxysporum f. sp. melonis strain T-SD3.

A novel mitovirus was identified in Fusarium oxysporum f. sp. melonis strain T-SD3 and designated as "Fusarium oxysporum mitovirus 3" (FoMV3). The virus was isolated from diseased muskmelon plants with the typical symptom of fusarium wilt. The complete genome of FoMV3 is 2269 nt in length with a predicted AU content of 61.40% and contains a single open reading frame (ORF) using the fungal mitochondrial genetic code. The ORF was predicted to encode a polypeptide of 679 amino acids (aa) containing a conserved RNA-dependent RNA polymerase (RdRp) domain with a molecular mass of 77.39 kDa, which contains six conserved motifs with the highly conserved GDD tripeptide in motif IV. The 5'-untranslated region (UTR) and 3'-UTR of FoMV3 were predicted to fold into stem-loop structures. BLASTp analysis revealed that the RdRp of FoMV3 shared the highest aa sequence identity (83.85%) with that of Fusarium asiaticum mitovirus 5 (FaMV5, a member of the family Mitoviridae) infecting F. asiaticum, the causal agent of wheat fusarium head blight. Phylogenetic analysis further suggested that FoMV3 is a new member of the genus Unuamitovirus within the family Mitoviridae. This is the first report of a new mitovirus associated with F. oxysporum f. sp. melonis.

Effects of Cucumis melo and Citrullus lanatus extracts on glucose level, lipid profile and hepato-renal performance of streptozotocin-induced diabetic albino rats.

Diabetes mellitus, recognized by elevated glucose level in the body fluids is commonly caused by less insulin production or its action. To overcome the complications of diabetes, chemical drugs are never preferred over herbal medicines. Present study was designed to find out the anti-diabetic and health-promoting effects of ethanolic leaf extracts of Cucumis melo and Citrullus lanatus in induced-diabetic albino rats. Thirty male albino rats were bought from the animal house of the university and divided randomly into five feeding groups (n=6). Diabetes was induced in rats of groups A, B, C & D by a single dose of intra-peritoneal injection of streptozotocin (55 mg/Kg), whereas, the rats of group E were considered as control. The rats of groups A, B & C were fed basal diet supplemented with plant extracts (150mg/Kg body weight), whereas; only basal diet was offered to rats of groups D & E. After 28 days of the experiment, blood was collected for biochemical analysis. Results revealed that body weight, glucose, AST, ALB, GGT, HDL, cholesterol, triglyceride, urea and creatinine level differed significantly among treatment groups. It was therefore concluded that ethanolic leaf extracts of Cucumis melo and Citrullus lanatus can be used separately or in combination for the management of diabetes.

Development of Rapid Detection Methods for Fusarium oysporum f. sp. melonis in Melon Seeds.

Melon (Cucumis melo L.) is a global commercial crop that is sensitive to seed-borne wilt infections caused by Fusarium oxysporum f. sp. melonis (Fom). To address the challenge of detecting Fom contamination, we designed a probe-based real-time PCR method, TDCP2, in combination with rapid or column-based DNA extraction protocols to develop reliable molecular detection methods. Utilizing TDCP2, the detection rate reached 100% for both artificially Fom-inoculated (0.25-25%) and pod-inoculated melon seeds in conjunction with DNA samples from either the rapid or column-based extraction protocol. We performed analyses of precision, recall, and F1 scores, achieving a maximum F1 score of 1 with TDCP2, which highlights the robustness of the method. Additionally, intraday and interday assays were performed, which revealed the high reproducibility and stability of column-based DNA extraction protocols combined with TDCP2. These metrics confirm the reliability of our developed protocols, setting a foundation for future enhancements in seed pathology diagnostics and potentially broadening their applicability across various Fom infection levels. In the future, we hope that these methods will reduce food loss by improving the control and management of melon diseases.

Uncovering the molecular mechanism of Mume Fructus in treatment of Sjögren's syndrome.

BACKGROUND: Modern medicine has no cure for the xerostomia caused by the early onset of Sjögren's syndrome. Mume Fructus is a common Chinese herbal medicine used to relieve xerostomia. However, the molecular mechanisms of the effects of Mume Fructus are unknown. In this study, network pharmacology and molecular docking were used to investigate the mechanisms of action of Mume Fructus on Sjögren's syndrome. MATERIALS AND METHOD: The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform database was used to identify the active components and targets of Mume Fructus, and the UniProt database was used to identify the genes encoding these targets. SS-related targets were also identified from the GeneCards and OMIM databases. By finding the intersection of the targets of the compounds and the targets of Sjögren's syndrome, the predicted targets of Mume Fructus in the treatment of Sjögren's syndrome were obtained. Further investigation of the active compounds and their targets was carried out by constructing a network of "medicine-candidate compound-target-disease" using Cytoscape 3.7.2, the Protein-Protein Interaction network using the STRING database and Cytoscape 3.7.2, and key targets were identified by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis on R software. Finally, molecular docking was used to verify the affinity of the candidate compounds to the key targets. RESULTS: Quercetin, beta-sitosterol, and kaempferol in Mume Fructus interact with AKT1, IL-6, IL-1B, JUN, CASP3, and MAPK8. These results suggest that Mume Fructus exerts its therapeutic effects on the peripheral gland injury of Sjögren's syndrome and its secondary cardiovascular disease and tumorigenesis through anti-inflammatory, anti-oxidant, and anti-tumor pathways. CONCLUSION: With network pharmacology, this study systematically identified the main active components, targets, and specific mechanisms of the therapeutic effects of Mume Fructus on Sjögren's syndrome, providing both a theoretical basis and research direction for further investigations on Mume Fructus.

Salmonella Saintpaul outbreak associated with cantaloupe consumption, the United Kingdom and Portugal, September to November 2023.

In September 2023, the UK Health Security Agency identified cases of Salmonella Saintpaul distributed across England, Scotland, and Wales, all with very low genetic diversity. Additional cases were identified in Portugal following an alert raised by the United Kingdom. Ninety-eight cases with a similar genetic sequence were identified, 93 in the United Kingdom and 5 in Portugal, of which 46% were aged under 10 years. Cases formed a phylogenetic cluster with a maximum distance of six single nucleotide polymorphisms (SNPs) and average of less than one SNP between isolates. An outbreak investigation was undertaken, including a case-control study. Among the 25 UK cases included in this study, 13 reported blood in stool and 5 were hospitalized. One hundred controls were recruited via a market research panel using frequency matching for age. Multivariable logistic regression analysis of food exposures in cases and controls identified a strong association with cantaloupe consumption (adjusted odds ratio: 14.22; 95% confidence interval: 2.83-71.43; p-value: 0.001). This outbreak, together with other recent national and international incidents, points to an increase in identifications of large outbreaks of Salmonella linked to melon consumption. We recommend detailed questioning and triangulation of information sources to delineate consumption of specific fruit varieties during Salmonella outbreaks.

Post-harvest quality of melon accessions subjected to salinity.

The objective was to evaluate the behavior of melon genotypes (Cucumis melo L.) in the physical, chemical and biochemical quality of melon fruits as a function of electrical conductivity irrigation water levels (ECw). The experimental design adopted was randomized blocks in a 5 x 3 factorial scheme with five replications. The first factor was represented by five salinity levels (0.5, 1.5, 3.0, 4.5, and 6.0 dS m-1) and the second factor by accessions A35, and A24, and the hybrid Sancho. The physical, chemical and biochemical variables showed a reduction in production, with smaller fruits, with less weight, smaller cavity, with increased pulp thickness for Sancho. Vitamin C and yellow flavonoids increased indicating antioxidant power against ROS. The genotypes showed similar post-harvest behavior, however, the hybrid Sancho stood out over the others, possibly because it is an improved material. Accession A24 presented physiological and biochemical responses that classify it as intolerant.

Transcriptomic analysis provides an insight into the function of CmGH9B3, a key gene of ß-1, 4-glucanase, during the graft union healing of oriental melon scion grafted onto squash rootstock.

The melon (Cucumis melo L.) is a globally cherished and economically significant crop. The grafting technique has been widely used in the vegetative propagation of melon to promote environmental tolerance and disease resistance. However, mechanisms governing graft healing and potential incompatibilities in melons following the grafting process remain unknown. To uncover the molecular mechanism of healing of grafted melon seedlings, melon wild type (Control) and TRV-CmGH9B3 lines were obtained and grafted onto the squash rootstocks (C. moschata). Anatomical differences indicated that the healing process of the TRV-CmGH9B3 plants was slower than that of the control. A total of 335 significantly differentially expressed genes (DEGs) were detected between two transcriptomes. Most of these DEGs were down-regulated in TRV-CmGH9B3 grafted seedlings. GO and KEGG analysis showed that many metabolic, physiological, and hormonal responses were involved in graft healing, including metabolic processes, plant hormone signaling, plant MAPK pathway, and sucrose starch pathway. During the healing process of TRV-CmGH9B3 grafted seedlings, gene synthesis related to hormone signal transduction (auxin, cytokinin, gibberellin, brassinolide) was delayed. At the same time, it was found that most of the DEGs related to the sucrose pathway were down-regulated in TRV-CmGH9B3 grafted seedlings. The results showed that sugar was also involved in the healing process of melon grafted onto squash. These results deepened our understanding of the molecular mechanism of GH9B3, a key gene of ß-1, 4-glucanase. It also provided a reference for elucidating the gene mechanism and function analysis of CmGH9B3 in the process of graft union healing.

Bacterial diversity and composition on the rinds of specific melon cultivars and hybrids from across different growing regions in the United States.

The goal of this study was to characterize the bacterial diversity on different melon varieties grown in different regions of the US, and determine the influence that region, rind netting, and variety of melon has on the composition of the melon microbiome. Assessing the bacterial diversity of the microbiome on the melon rind can identify antagonistic and protagonistic bacteria for foodborne pathogens and spoilage organisms to improve melon safety, prolong shelf-life, and/or improve overall plant health. Bacterial community composition of melons (n = 603) grown in seven locations over a four-year period were used for 16S rRNA gene amplicon sequencing and analysis to identify bacterial diversity and constituents. Statistically significant differences in alpha diversity based on the rind netting and growing region (p < 0.01) were found among the melon samples. Principal Coordinate Analysis based on the Bray-Curtis dissimilarity distance matrix found that the melon bacterial communities clustered more by region rather than melon variety (R2 value: 0.09 & R2 value: 0.02 respectively). Taxonomic profiling among the growing regions found Enterobacteriaceae, Bacillaceae, Microbacteriaceae, and Pseudomonadaceae present on the different melon rinds at an abundance of ≥ 0.1%, but no specific core microbiome was found for netted melons. However, a core of Pseudomonadaceae, Bacillaceae, and Exiguobacteraceae were found for non-netted melons. The results of this study indicate that bacterial diversity is driven more by the region that the melons were grown in compared to rind netting or melon type. Establishing the foundation for regional differences could improve melon safety, shelf-life, and quality as well as the consumers' health.

Exogenous Melatonin Application Accelerated the Healing Process of Oriental Melon Grafted onto Squash by Promoting Lignin Accumulation.

Melatonin (MT) is a vital hormone factor in plant growth and development, yet its potential to influence the graft union healing process has not been reported. In this study, we examined the effects of MT on the healing of oriental melon scion grafted onto squash rootstock. The studies indicate that the exogenous MT treatment promotes the lignin content of oriental melon and squash stems by increasing the enzyme activities of hydroxycinnamoyl CoA ligase (HCT), hydroxy cinnamaldehyde dehydrogenase (HCALDH), caffeic acid/5-hydroxy-conifer aldehyde O-methyltransferase (COMT), caffeoyl-CoA O-methyltransferase (CCoAOMT), phenylalanine ammonia-lyase (PAL), 4-hydroxycinnamate CoA ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD). Using the oriental melon and squash treated with the exogenous MT to graft, the connection of oriental melon scion and squash rootstock was more efficient and faster due to higher expression of wound-induced dedifferentiation 1 (WIND1), cyclin-dependent kinase (CDKB1;2), target of monopteros 6 (TMO6), and vascular-related NAC-domain 7 (VND7). Further research found that the exogenous MT increased the lignin content of the oriental melon scion stem by regulating CmCAD1 expression, and then accelerated the graft healing process. In addition, the root growth of grafted seedlings treated with the exogenous MT was more vigorous.

Cuticle properties, wax composition, and crystal morphology of Hami melon cultivars (Cucumis melo L.) with differential resistance to fruit softening.

Cuticle wax chemicals are cultivar-dependent and contribute to storage quality. Few research reported on wax analysis between melting flesh-type (MF; 'Jinhuami 25') and nonmelting flesh-type (NMF; 'Xizhoumi 17' and 'Chougua') Hami melons. Chemicals and crystal structures of Hami melon cuticular wax, cell wall metabolism related to fruit melting, and fruit physiology were analyzed to observe wax functions. Results showed that Hami melon cuticle wax predominantly consists of esters, alkanes, alcohols, aldehydes, and terpenoids. MF-type has a lower alkane/terpenoid ratio, concomitant to its higher weight loss and cuticle permeability. Micromorphology of wax crystals appears as numerous platelets with irregular crystals, and the transformation of wax structure in NMF Hami melon is delayed. Waxy components affect cell wall metabolism and physiological quality, which results in the pulp texture difference between MF-type and NMF-type during storage. Results provide a reference for the regulation of wax synthesis in both types of melons.

Biocontrol of Escherichia coli O157:H7 by Enterobacter asburiae AEB30 on intact cantaloupe melons.

Escherichia coli O157:H7 causes >73,000 foodborne illnesses in the United States annually, many of which have been associated with fresh ready-to-eat produce including cantaloupe melons. In this study, we created a produce-associated bacterial (PAB) library containing >7500 isolates and screened them for the ability to inhibit the growth of E. coli O157:H7 using an in vitro fluorescence-based growth assay. One isolate, identified by 16S and whole-genome sequence analysis as Enterobacter asburiae, was able to inhibit the growth of E. coli by ~30-fold in vitro and produced zones of inhibition between 13 and 21 mm against 12 E. coli outbreak strains in an agar spot assay. We demonstrated that E. asburiae AEB30 was able to grow, persist and inhibit the growth of E. coli on cantaloupe melons under simulated pre- and post-harvest conditions. Analysis of the E. asburiae AEB30 genome revealed an operon encoding a contact-dependent growth inhibition (CDI) system that when mutated resulted in the loss of E. coli growth inhibition. These data suggest that E. asburiae AEB30 is a potential biocontrol agent to prevent E. coli contamination of cantaloupe melons in both pre- and post-harvest environments and that its mode of action is via a CDI system.

Time-Series Transcriptome of Cucumis melo Reveals Extensive Transcriptomic Differences with Different Maturity.

As the most important melon cultivar grown in the north-western provinces of China, Hami melon (Cucumis melo) produces large edible fruits that serve as an important dietary component in the world. In general, as a climacteric plant, melon harvested at 60% maturity results in a product with bad quality, while the highest-quality product can be guaranteed when harvesting at 90% maturity. In order to clarify the genetic basis of their distinct profiles of metabolite accumulation, we performed systematic transcriptome analyses between 60% and 90% maturity melons. A total of 36 samples were sequenced and over 1.7 billion reads were generated. Differentially expressed genes in 60% and 90% maturity melons were detected. Hundreds of these genes were functionally enriched in the sucrose and citric acid accumulation process of C. melo. We also detected a number of distinct splicing events between 60% and 90% maturity melons. Many genes associated with sucrose and citric acid accumulation displayed as differentially expressed or differentially spliced between different degrees of maturity of Hami melons, including CmCIN2, CmSPS2, CmBGAL3, and CmSPS2. These results demonstrate that the phenotype pattern differences between 60% and 90% maturity melons may be largely resulted from the significant transcriptome regulation.

Identification and characterization analysis of the HDM gene family in melon (Cucumis melo L.).

Histone demethylase (HDM) play crucial roles in regulating plant growth and environmental adaptation. In this study, the HDM gene family in melon was identified by bioinformatics methods and the expression patterns of the CmHDM family members in different melon tissues were analyzed using transcriptome data. The results showed that 20 CmHDM genes were identified in the melon genome, which were unevenly distributed across each chromosome. These members fall into two major categories: LSD1 and JmjC. The JmjC group could be further divided into five subgroups with different numbers. The results of collinearity analysis of intraspecific and interspecific relationships showed that there were only one pair of segmental duplication in melon HDM genes, and more collinearity in genetic relationship of HDM genes between melon and tomato. The numbers of conserved domains, exons and introns in each member vary and various cis-acting elements responding to hormones and environmental signals existed in the respective promoter regions. Expression analysis showed that the respective gene members were expressed at different levels in male flowers, female flowers, roots, stems, leaves, ovary, and mature fruits of melon. These results will contribute to the understanding on the potential functions of the HDM genes and their potential functions in regulating melon growth and environmental adaptation.

The effects of different rootstocks on aroma components, activities and genes expression of aroma-related enzymes in oriental melon fruit.

Grafting is widely applied in the cultivation of melon. In this study, 'Qinmi No.1' (Cucumis melo L.(QG)) and 'Ribenxuesong' (Cucurbita maxima Duch. (RG)) were used as rootstocks for 'Qingxin Yangjiaocui' (Cucumis melo L.). The results showed that grafting with muskmelon rootstocks had no significant effect on fruit aroma, but grafting with pumpkin rootstocks significantly reduced the odor intensity and odor preference scores of melon fruits. Compared with the fruits from self-grafted plants (SG), four new aromatic volatiles with a sweet smell were detected, the alcohol dehydrogenase (ADH) activity was significantly decreased at 30 DAP, but unaffected at 42 DAP in QG fruits. There was no difference for alcohol acetyltransferase (AAT) activity between QG and SG fruits. The expression level of CmADH2 was significantly higher at 30 DAP and 42 DAP, but CmAAT2 was significantly lower at 42 DAP in QG fruits compared with SG fruits. In RG fruits, the main aroma compounds including butanoic acid ethyl ester, 2-methyl-2-butene-1-al, and 2-methylheptan-1-al were absent, while the volatile compounds with unpleasant odor characteristics including trans, cis-2,6-nonadien-1-ol, (E,E)-2,4-heptadienal, octanoic acid, and styrene were detected. Compared with SG fruits, 1-nonanol and 1-heptanol with green odor characteristics were significantly increased, but eucalyptol and farnesene with fruity aroma characteristics were significantly decreased in RG fruits. The ADH activity of RG fruits was significantly lower than that of SG fruits at 30 DAP and the AAT activity was significantly lower than that of SG fruits at 42 DAP. In addition, the expression levels of CmADH and CmAAT homologs in RG fruits were significantly lower than those in SG or QG fruits. These results show that grafting with pumpkin rootstocks affected the main aroma components, reduced ADH and AAT activities, and down-regulated the expression levels of CmADHs and CmAATs in the melon fruits. This study reveals the mechanism of different rootstocks on melon fruit aroma quality, and lays a theoretical foundation for the selection of rootstocks in melon production. Future studies using overexpression or CRISPR/CAS system to obtain stable transgenic lines of genes encoding key aromatic volatiles, would be promising to effectively improve the flavor quality of melon.

CmCML11 interacts with CmCAMTA5 to enhance γ-aminobutyric acid (GABA) accumulation by regulating GABA shunt in fresh-cut cantaloupe.

The effect of calcium chloride (CaCl2) treatment on γ-aminobutyric acid (GABA) accumulation in fresh-cut cantaloupe and the involved mechanisms were investigated. The result showed that 1% (w/v) CaCl2 treatment increased GABA content and activities of glutamate decarboxylase (GAD) and succinate semialdehyde dehydrogenase (SSADH), while decreased glutamate (Glu) content and GABA transaminase (GABA-T) activities in fresh-cut cantaloupe. CmCML11 and CmCAMTA5 expressions of CaCl2-treated fruit increased by 187.4% and 165.6% than control fruit in the initial 6 h. Besides, expressions of GABA shunt genes, including CmGAD1, CmGAD2, CmGABA-T and CmSSADH were also up-regulated by CaCl2 treatment during early storage. Moreover, acting as a transcriptional activator, CmCAMTA5 could bind to the CG-box in promoters of CmGAD1, CmGABA-T and CmSSADH and activate their transcription. Furthermore, the interaction between CmCML11 and CmCAMTA5 could enhance the transcriptional activation on GABA shunt genes which were regulated by CmCAMTA5. Collectively, our findings revealed that CaCl2 treatment promoted GABA accumulation in fresh-cut cantaloupe via the combined effect of CmCML11 and CmCAMTA5 in the regulation of expressions of CmGAD1, CmGABA-T, and CmSSADH in GABA shunt.

Genome-wide identification of the melon (Cucumis melo L.) response regulator gene family and functional analysis of CmRR6 and CmPRR3 in response to cold stress.

The response regulator (RR) gene family play crucial roles in cytokinin signal transduction, plant development, and resistance to abiotic stress. However, there are no reports on the identification and functional characterization of RR genes in melon. In this study, a total of 18 CmRRs were identified and classified into type A, type B, and clock PRRs, based on phylogenetic analysis. Most of the CmRRs displayed tissue-specific expression patterns, and some were induced by cold stress according to two RNA-seq datasets. The expression patterns of CmRR2/6/11/15 and CmPRR2/3 under cold treatment were confirmed by qRT-PCR. Subcellular localization assays indicated that CmRR6 and CmPRR3 were primarily localized in the nucleus and chloroplast. Furthermore, when either CmRR6 or CmPRR3 were silenced using tobacco ringspot virus (TRSV), the cold tolerance of the virus-induced gene silencing (VIGS) melon plants were significantly enhanced, as evidenced by measurements of chlorophyll fluorescence, ion leakage, reactive oxygen, proline, and malondialdehyde levels. Additionally, the expression levels of CmCBF1, CmCBF2, and CmCBF3 were significantly increased in CmRR6-silenced and CmPRR3-silenced plants under cold treatment. Our findings suggest that CmRRs contribute to cold stress responses and provide new insights for further pursuing the molecular mechanisms underlying CmRRs-mediated cold tolerance in melon.

Exploring the effect and mechanism of cucurbitacin B on cholestatic liver injury based on network pharmacology and experimental verification.

ETHNOPHARMACOLOGICAL RELEVANCE: Cholestatic liver injury (CLI) is a pathologic process with the impairment of liver and bile secretion and excretion, resulting in an excessive accumulation of bile acids within the liver, which leads to damage to both bile ducts and hepatocytes. This process is often accompanied by inflammation. Cucumis melo L is a folk traditional herb for the treatment of cholestasis. Cucurbitacin B (CuB), an important active ingredient in Cucumis melo L, has significant anti-inflamamatory effects and plays an important role in diseases such as neuroinflammation, skin inflammation, and chronic hepatitis. Though numerous studies have confirmed the significant therapeutic effect of CuB on liver diseases, the impact of CuB on CLI remains uncertain. Consequently, the objective of this investigation is to elucidate the therapeutic properties and potential molecular mechanisms underlying the effects of CuB on CLI. AIM OF THE STUDY: The aim of this paper was to investigate the potential protective mechanism of CuB against CLI. METHODS: First, the corresponding targets of CuB were obtained through the SwissTargetPrediction and SuperPre online platforms. Second, the DisGeNET database, GeneCards database, and OMIM database were utilized to screen therapeutic targets for CLI. Then, protein-protein interaction (PPI) was determined using the STRING 11.5 data platform. Next, the OmicShare platform was employed for the purpose of visualizing the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The molecular docking technique was then utilized to evaluate the binding affinity existing between potential targets and CuB. Subsequently, the impacts of CuB on the LO2 cell injury model induced by Lithocholic acid (LCA) and the CLI model induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) were determined by evaluating inflammation in both in vivo and in vitro settings. The potential molecular mechanism was explored by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot (WB) techniques. RESULTS: A total of 122 CuB targets were collected and high affinity targets were identified through the PPI network, namely TLR4, STAT3, HIF1A, and NFKB1. GO and KEGG analyses indicated that the treatment of CLI with CuB chiefly involved the inflammatory pathway. In vitro study results showed that CuB alleviated LCA-induced LO2 cell damage. Meanwhile, CuB reduced elevated AST and ALT levels and the release of inflammatory factors in LO2 cells induced by LCA. In vivo study results showed that CuB could alleviate DDC-induced pathological changes in mouse liver, inhibit the activity of serum transaminase, and suppress the liver and systemic inflammatory reaction of mice. Mechanically, CuB downregulated the IL-6, STAT3, and HIF-1α expression and inhibited STAT3 phosphorylation. CONCLUSION: By combining network pharmacology with in vivo and in vitro experiments, the results of this study suggested that CuB prevented the inflammatory response by inhibiting the IL-6/STAT3/HIF-1α signaling pathway, thereby demonstrating potential protective and therapeutic effects on CLI. These results establish a scientific foundation for the exploration and utilization of natural medicines for CLI.