Oil palm is an important tropical woody oilseed crop. Its fruit is rich in flavonoids, which possess high nutritional value and exhibit antioxidant, anti-inflammatory, and antibacterial activities. The molecular mechanism underlying flavonoid biosynthesis in oil palm remains unclear. In this study, we performed LC-MS/MS and RNA-Seq analyses to investigate the molecular regulatory mechanism of flavonoid accumulation in oil palm exocarp. Exocarps from virescens (FS) and nigrescens (FT) at 95, 125, and 185 days after pollination were used as experimental materials to characterize the metabolome and transcriptome at different developmental stages. Our objectives were to identify flavonoid metabolite types, key biosynthetic genes, and related biological metabolic pathways in oil palm exocarp. A total of 274 flavonoids were identified in FS and 275 in FT. Across the three developmental stages, the flavonoid content in FT was higher than that in FS. The differentially accumulated metabolites were mainly enriched in three pathways: flavonoid biosynthesis, flavone and flavonol biosynthesis, and anthocyanin biosynthesis. Combined metabolomic and transcriptomic analyses allowed the reconstruction of the flavonoid biosynthetic pathway and the identification of enzyme genes and metabolites involved in flavonoid synthesis. For FS, six enzyme genes and seven differentially accumulated metabolites were involved. For FT, eight enzyme genes and nine metabolites were involved. This study preliminarily developed 9 pairs of KASP molecular markers (K2-K10). In field tests using 30 FS individuals and 30 FT individuals, these markers were used to evaluate the consistency between genotypes and corresponding phenotypes.The identification accuracy reached 100% within the tested population.These 9 marker pairs are closely linked to the EgDFR gene and can effectively distinguish FS from FT. This study clarifies the flavonoid biosynthesis mechanism in the exocarp of oil palm fruits and develops markers associated with flavonoid biosynthesis. It helps improve the ornamental value of oil palm, and allows the identification of variety purity and type at the seedling stage. This shortens the breeding cycle of oil palm. It provides a resource basis for the breeding and utilization of oil palm varieties, the screening of high‑flavonoid germplasm, and the development of related products.
Brassinosteroids (BRs) are a class of biologically active steroid plant hormones that play a central role in the growth and development of horticultural crops, the formation of fruit quality, and adaptation to abiotic stresses through the activation of multiple signaling pathways. Although foundational BR research has been relatively thorough in model plants and staple crops, there is still a lack of systematic reviews focusing on the molecular mechanisms underlying preharvest quality regulation and postharvest preservation in horticultural crops, particularly fruit trees. This study systematically reviews the biosynthesis and signal transduction network of BRs, with an emphasis on their critical functions in enhancing the quality of horticultural crops, especially the regulatory mechanisms governing fruit color, flavor, and nutritional composition. Furthermore, the potential application of BRs in postharvest preservation is explored in detail, revealing their physiological and biochemical mechanisms in delaying senescence, inhibiting pathogens, and maintaining postharvest fruit quality. Finally, the current research challenges and future directions are discussed. This review aims to provide a theoretical foundation for research on BRs in fruit development and postharvest physiological regulation, and to offer insights for the technological innovation and application in smart horticulture.
Durian (Durio zibethinus L.) is widely regarded as the 'king of fruits', and Musang King is a premium cultivar whose intense pulp aroma drives consumer preference and market value. However, the chemical determinants and molecular regulation of ripening-associated aroma transitions remain poorly understood. Here, volatile profiling and transcriptomic analyses were integrated to characterize aroma transitions and their regulatory basis across four ripening stages. In total, 420 volatile organic compounds were detected, and four aroma-active markers were identified based on multivariate analysis and odour activity evaluation. Early-stage pulp was dominated by LOX-derived C6/C9 aldehydes associated with green notes, whereas ripening featured pronounced increase in ethyl esters (fruity-sweet) and organosulfur volatiles contributing to cultivar-specific aroma characteristics. Transcriptome analysis revealed coordinated regulation of fatty acid and sulfur amino acid metabolism, with LOX-HPL-ADH and β-oxidation gene expression closely tracked the aldehyde-to-ester shift. WGCNA identified stage-associated modules correlated with representative aldehydes and esters, highlighting candidate hub genes for aroma remodeling, such as Dz13-LOX1 and DzACX1. Functional assays further supported hormone-associated transcriptional regulation of key aroma-pathway genes. These results elucidate the regulatory framework underlying aroma maturation in Musang King durian and propose practical metabolic and molecular markers for flavour quality assessment and value-added food applications.
Fruits of Rosa acicularis are recognized for their high nutritional value owing to accumulation of diverse bioactive metabolites. However, the physiological processes and regulatory mechanisms underlying quality formation remain incompletely understood. In this study, developmental changes in fruit quality were assessed across four stages: the mature green stage (MGS), breaker stage (BS), maturity stage (MS), and ripening stage (RS), using morphological, physicochemical, and antioxidant analyses. To further elucidate the molecular regulatory basis of ripening, three representative stages (MGS, BS, and RS) were selected for transcriptomic and metabolomic profiling. Results indicated coordinated fruit enlargement and pigmentation, accompanied by stage-dependent alterations in sugars, organic acids, pectin, polysaccharides, and vitamin C. Antioxidant capacity exhibited distinct radical-specific response patterns throughout ripening. Transcriptomic profiling identified 10,841 differentially expressed genes, which were predominantly enriched in pathways associated with hormone signal transduction, carbohydrate metabolism, flavonoid biosynthesis, and phenylpropanoid biosynthesis. Metabolomic analysis detected 1305 metabolites, among which flavonoids constituted the dominant class and displayed pronounced temporal dynamics. Integrated temporal expression analysis demonstrated strong co-expression between gene expression and metabolite accumulation. WGCNA further identified the MEblack module as the module most closely associated with flavonoid traits, with hub genes including RaWRKY56, RaC3H53, RaNF-YA4, and RaF3'H predicted as key regulatory factors, a result supported by qRT-PCR expression profiles. These findings establish an integrated molecular framework for elucidating quality formation in R. acicularis and provide potential genetic targets for future improvement and utilization.
Mulberry is an economically important sericulture crop; however, infection by root-knot nematodes (RKNs) poses a serious threat to its production. We observed a high density of RKNs parasitizing mulberry in Yunnan, China. To identify the pathogenic species, we characterized the nematode using morphometric analysis, rDNA/mtDNA-based phylogenetics, and SCAR-PCR. Subsequently, we artificially inoculated healthy mulberry seedlings with second-stage juveniles (J2s) to assess their pathogenicity. The perineal pattern of females is round to ovoid, featuring a moderately high dorsal arch and two large, prominent phasmids, similar to that of Meloidogyne vitis. The morphological and morphometric traits of females, J2s, and males were consistent with those of M. vitis. Genetic analyses further confirmed this, as the rDNA (ITS1-5.8 S-ITS2) and mtDNA (coxI and coxII) sequences showed > 99% similarity to M. vitis and clustered within the same clade with high support (99%-100%). Moreover, species identity was further confirmed using M. vitis-specific primers Mv-F/R, and a single specific fragment of 174 bp was obtained. Artificial inoculation demonstrated that the RKN isolated from mulberry could complete its life cycle in the roots of healthy seedlings of mulberry, producing typical root-knots and egg masses. The RKN parasitizing in mulberry was confirmed as M. vitis based on the morphological features and molecular results. This is the first report of M. vitis attacking mulberry. M. vitis is capable of infecting and damaging mulberry, posing a potential threat to mulberry production. The results of this study providing a theoretical basis for accurately identifying and implementing future effective and integrated nematodes management strategy to safeguard mulberry cultivation.
Embryo abortion impedes hybrid breeding and limits development of the economically important Chinese jujube (Ziziphus jujuba Mill.) industry. To elucidate hormonal regulation of jujube embryogenesis, transcriptomic, proteomic, and hormone content analyses were performed on high- and low-fertility embryos at 30, 40, and 50 days of development. Differentially expressed genes (DEGs) and proteins (DEPs) were screened and subjected to functional enrichment analysis, cluster analysis, and interaction network analysis. DEGs and DEPs were enriched in plant hormone signal transduction. The expression patterns of genes and proteins in the hormone signaling pathways of jujube embryos with different fertility levels varied significantly yet were interrelated. Hormone dynamic analysis indicated a decrease in indole-3-acetic acid (IAA) content and excessive accumulation of abscisic acid (ABA) and ethylene (ACC) in low-fertility embryos, resulting in the imbalance of (IAA + CTK + GA3)/(ABA + ACC). These findings provide novel targets for molecular breeding to improve jujube fruit set.
The α-amylase enzyme plays a vital role in enzyme therapy and the intestinal digestive system, and is widely utilized in the food and pharmaceutical industries. Thus, this study aimed to isolate intestinal bacterial strains that produce α-amylase, optimize enzyme production, and characterize the molecular properties of the produced proteins. A total of 11 strains were isolated from the fish gut; 9 strains were positive for α-amylase production. The PS5 strain exhibited the highest enzymatic activity and was confirmed as Bacillus cereus. Optimization of B. cereus culture conditions revealed parameters of pH 7.0, temperature 35 °C, incubation time 40 h, and starch and yeast extracts of 1.5% and 2.53%, respectively. The bacterial protein was extracted, purified, and shown to have a molecular weight of 55 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. FTIR spectroscopy confirmed the presence of functional groups, such as phenols, alkanes, amides, and aromatic and aliphatic amines. Matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF)-tandem mass spectrometry (MS/MS) analysis identified 12 peptides, with the major peptide sequence being SVGLLLVLLLPMLGAAAPLTTQMLDSGWQFR (m/z 2383.97; S/N 69.3). The α-amylase protein sequence (513 amino acids) was used for structural prediction, while protein-protein interaction analysis revealed a significant interaction with pullulanase (interaction score 0.945). Molecular docking analysis showed strong binding energy of propoxur (-7.2 kcal/mol) and the hormone indole-3-acetic acid (-6.9 kcal/mol) with α-amylase protein. These findings indicate that Bacillus cereus (PS5) is a promising source of α-amylase for diverse industrial and agricultural applications. Further investigation into the activity and stability of these enzymes in natural environments could enhance the associated potential biotechnological applications.
The stay-green trait, which manifests as a delayed leaf senescence in plants, is increasingly viewed as a valuable target for improving crop resilience, quality and yield stability. While most of the progress in this area has been made in cereals, research in legumes remains less consolidated, despite their importance for nutrition and sustainable agriculture. Bibliometric and structured literature reviews were combined to examine the evolution, thematic structure, and research frontiers of stay-green research in legumes over the past 3 decades. Using the Web of Science Core Collection and Dimensions database, 157 relevant articles published between 1993 and 2025 were identified following PRISMA guidelines and analyzed using VOSviewer and the Bibliometrix R framework to assess publication trends, collaboration networks, thematic evolution, and to classify reported stay-green phenotypes into functional and non-functional categories. The results show a steady rise in publications with a growth rate of 8.6% per year, involving 883 authors across 96 journals, and a strong pattern of international collaboration. Most publications were original research articles, with only 11 review articles, indicating a lack of integrative work in this field. Foundational work by Thomas and colleagues remains highly influential, while recent studies increasingly emphasize molecular genetics and functional analyses in soybean, common bean, pea, and other grain legumes. The keyword analysis highlighted five main research hotspots: drought tolerance, molecular regulation of senescence, photosynthesis related mechanisms, trait mapping and genomics, and pathological stay-green syndromes. Research emphasis has shifted from descriptive physiology toward molecular breeding applications, with increasing focus on distinguishing functional from non-functional stay-green. This is the first comprehensive study to apply bibliometric approaches to analyze the trends and research frontiers of stay-green traits in legumes, offering valuable insights and reference points for advancing future research and breeding applications.
Pistacia lentiscus L., which is extensively distributed across the Mediterranean region, has long been employed in traditional medicine for the management of various ailments, mainly due to its reported anti-inflammatory, antimicrobial, and antioxidant properties. Despite evidence supporting its anti-inflammatory potential, comprehensive studies integrating biological experiments with computational approaches remain limited. This paper focused on characterizing the anti-inflammatory potential of a hydro-methanol extract obtained from P. lentiscus leaves collected in northeastern Algeria (Jijel region).To achieve this objective, a multidisciplinary strategy combining chemical profiling, experimental pharmacological assays, and computational modeling was employed in order to investigate both the biological efficacy of the extract and the molecular basis of its anti-inflammatory action. The phytochemical profile of the extract was characterized using Gas chromatography-mass spectrometry (GC- MS) analysis. Its anti-inflammatory efficacy was assessed in vivo using the carrageenan-induced paw edema model in rats. In vitro assays were conducted to evaluate erythrocyte membrane stabilization and protease inhibitory activity. Additionally, molecular docking studies were executed to investigate the binding interactions between the defined molecules and basic proteins acting in inflammation. GC-MS analysis allowed the identification of 27 phytochemical constituents, among which shikimic acid was the most abundant (39.67%). Oral administration of the extract at 250 mg/kg produced a significant inhibition of paw edema (45.01%) after 120 min, surpassing the effect observed with the reference drug indomethacin (28.61%). In vitro experiments demonstrated a dose-dependent stabilization of erythrocyte membranes (41.42%) and pronounced protease inhibitory activity (82.43% at 50 μg/mL). Molecular docking results indicated that ethanone, 1-[4-methoxy-3-(4-methylphenoxy)phenyl]-, exhibited a high binding affinity toward inducible nitric oxide synthase (iNOS; PDB ID: 3E7G), with a predicted inhibition constant (Ki) of 0.128 μM, showing interaction patterns comparable to indomethacin. This study highlights the importance of natural anti-inflammatory agents as a promising source by presenting experimental and computational evidence supporting the potent anti-inflammatory potential of P. lentiscus leaf extract.
Fusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum (FOC), poses a major threat to economically important crops worldwide. Figleaf gourd (Cucurbita ficifolia) has been widely adopted as a rootstock for FOC-susceptible cucumber (Cucumis sativus) due to its strong resistance, although the underlying molecular mechanisms remain elusive. In this study, we leveraged the contrasting FOC resistance between C. ficifolia and C. sativus to perform a comparative analysis aimed at elucidating the molecular basis of Fusarium wilt resistance in C. ficifolia. Compared to C. sativus, resistant C. ficifolia exhibited milder wilting, enhanced antioxidant enzyme activities, and reduced oxidative damage. Transcriptome profiling revealed 1,599 species-specific expressed genes and 3,379 orthologous genes with interspecies expression divergence. Several key defense-related pathways, such as MAPK signaling and plant-pathogen interaction, contained critical node genes that exhibited species-specific regulation, potentially contributing to the enhanced resistance of C. ficifolia. This global divergence in gene expression was associated with distinct metabolic shifts, leading to the specific activation of defense-related metabolic pathways in C. ficifolia and the subsequent accumulation of protective compounds such as brassinosteroids, phenylpropanoids, and flavonoids. These findings indicate that C. ficifolia's superior FOC resistance is not attributable to a single factor but emerges from a sophisticated orchestration of gene expression and metabolic output. This study provides novel molecular insights into Fusarium wilt resistance and offers candidate genes and metabolic targets for breeding disease-resistant cucurbit crops.
Peanut (Arachis hypogaea L.) is an important oil and economic crop, and its production has long been severely threatened by soil-borne bacterial wilt (BW) disease. However, the molecular mechanism of host resistance to it has not yet been systematically elucidated. In this study, the highly resistant peanut variety Zhonghua 6 was used as the research object. Through transcriptomic analysis, a total of 1,122 differentially expressed genes (DEGs) were identified between carefully designed treatment and control groups. WGCNA analysis led to the discovery of 14 hub genes, including two cytochrome P450 genes and a UGDH gene. Through metabolomic analysis, 1,614 differentially accumulated metabolites (DAMs) were identified, and 6-methylcoumarin, erucamide, and piceatannol were confirmed to inhibit the growth of R. solanacearum. Integrative transcriptomic and metabolomic analyses uncovered a comprehensive immune regulatory network consisted of genes involved in key pathways associated with R. solanacearum infection such as MAPK signaling, plant hormone signal transduction, phenylpropanoid biosynthesis, flavonoid biosynthesis, and ABC transporter. Overall, these results provide new insights into the molecular mechanisms governing peanut resistance to R. solanacearum, which might assist in the mining of resistance-related genes, developing of new disease control measures as well as breeding of novel disease-resistant cultivars in peanut.
In perennial crops, a metabolic trade-off between defense-related and aroma-related compounds fundamentally shapes quality, yet its regulation remains elusive. Grafting is a key horticultural technique that can alter this balance in tea plants (Camellia sinensis), but the underlying molecular mechanisms are unclear. To decipher this rootstock-driven trade-off, we employed an integrated multi-omics approach in Camellia sinensis cv. 'Yashixiang Dancong' and Camellia sinensis cv. 'Lingtou Dancong'. Scions of the high-aroma cultivar 'Yashixiang' were grafted onto the vigorous 'Lingtou' rootstocks (hetero-grafting) and self-grafted (homo-grafting). We observed a pronounced metabolic trade-off: hetero-grafting significantly reduced phenylpropanoids (catechins) and caffeine (bitter-tasting compounds) while markedly enriching volatile terpenoids and fatty acid derivatives (aroma compounds). Transcriptome analysis revealed that this shift was orchestrated by a systematic transcriptional reprogramming mediating the trade-off: key gateway genes in the phenylpropanoid and caffeine pathways (CsPAL, Cs4CL, CsTCS) were downregulated, creating a bottleneck that limited flux toward non-volatile metabolites. Concurrently, genes encoding rate-limiting enzymes in the terpenoid backbone pathways (CsHMGR, CsDXS) were upregulated, enhancing precursor supply for volatile synthesis. This demonstrates that the rootstock genotype directs a precise metabolic trade-off in the scion, prioritizing aroma (terpenoids) production over defense (phenylpropanoids) accumulation. Our findings elucidate the molecular basis of grafting-modulated flavor quality and provide a framework for harnessing rootstock-scion interactions to fine-tune metabolic trade-offs in perennial crops.
Camellia reticulata 'Tongzimian' is the lightest-colored cultivar within the species, yet the molecular mechanism underlying its color formation remains elusive. In this study, 'Tongzimian' was used to observe phenotypic characteristics during flowering. Through multi-omics analyses, key substances and genes associated with petal fading were identified, clarifying the role of the CrANS gene in regulating floral coloration. Targeted anthocyanin metabolomics showed that procyanidin is the main pigment in 'Tongzimian' petals, with cyanidin serving as the key pigment driving color transformation. Transcriptome analysis revealed that low CrANS expression at full bloom is the primary factor reducing cyanidin content. Overexpressing CrANS demonstrated that the gene strongly promotes anthocyanin synthesis in tobacco corollas, thereby deepening flower color. The study suggests that a balance between cyanidin and procyanidin is central in regulating petal color transformation. Collectively, this research provides a novel framework for flower color dilution and supports molecular breeding of flower color in C. reticulata.
Wild orchid populations are declining with intensified habitat fragmentation posing severe challenges to germplasm conservation. As an important ornamental Orchidaceae species, Cymbidium ensifolium has abundant germplasm resources and frequent natural and artificial hybridization. Long-term natural evolution and anthropogenic disturbance have led to complex genetic backgrounds and ambiguous phylogenetic relationships hindering accurate germplasm identification, elite resource excavation, and selective breeding. As a distinctive variety, Cymbidium ensifolium var. susin has great breeding potential. Clarifying its phenotypic and genetic characteristics is crucial for accelerating breeding progress. In this study, phenotypic determination, Hyper-seq reduced-representation genome sequencing, SNP/InDel genotyping, genetic diversity analysis, and core collection construction were used to evaluate the genetic diversity, population differentiation, and core germplasm screening of 13 Cymbidium ensifolium var. susin accessions. The results showed significant phenotypic differences and rich genetic variation among tested materials. Based on highly weighted floral traits, accessions were divided into three major phenotypic groups. At the molecular level, 963,239 SNP and 182,399 InDel loci were identified and mainly distributed in intergenic regions, followed by introns and exons. A phylogenetic tree was constructed from SNP loci combined with principal component and phenotypic clustering analyses. This study preliminarily clarified the genetic structure of pure-heart Cymbidium ensifolium var. susin, showing a distinct geographical pattern: "high consistency in Fujian and Guangdong; strong differentiation in Southwest China; and a transitional gradient in Central China". Meanwhile, six core germplasm accessions were screened in this study, which provides a solid theoretical basis and material support for the conservation of pure-heart Cymbidium ensifolium var. susin accessions, variety improvement, hybrid parent selection, and molecular marker-assisted breeding. This is of great significance for promoting the innovation of Chinese orchid germplasm resources and the high-quality development of the industry.
Alternaria brown spot, caused by the tangerine pathotype of Alternaria alternata, is a destructive fungal disease affecting citrus production worldwide. Nucleotide-binding site-leucine-rich repeat (NBS-LRR) genes constitute a major class of plant immune receptors; however, their genome-wide characteristics and potential association with Alternaria brown spot resistance loci in citrus remain poorly understood. In this study, we performed a comprehensive genome-wide identification and comparative analysis of NBS-LRR genes across representative citrus species. A total of 417 and 326 NBS-LRR genes were identified in Citrus reticulata and Citrus clementina, respectively, and were classified into NL, CNL, TNL, and RNL subfamilies based on domain architecture. Phylogenetic reconstruction, gene structure analysis, conserved motif composition, chromosomal distribution, synteny relationships, and promoter cis-element profiling collectively revealed considerable structural variation and lineage-specific expansion of the NBS-LRR gene family in citrus genomes. By integrating previously reported quantitative trait locus (QTL) data for Alternaria brown spot, we identified several NBS-LRR genes located within a resistance-associated genomic interval on chromosome 3. Among these, a candidate gene, designated LRR2, exhibited differential transcriptional responses upon pathogen inoculation and displayed distinct sequence variations between citrus genotypes. Structural modeling and molecular docking analyses suggested potential binding interfaces between LRR2 and multiple host-selective toxins, although the biological relevance of these interactions requires further experimental validation. Subcellular localization assays in Nicotiana benthamiana showed that LRR2 is distributed in both the nucleus and cytoplasm. Notably, transient overexpression of LRR2 triggered hypersensitive response-like cell death and H2O2 accumulation. Collectively, this study provides a comprehensive overview of the citrus NBS-LRR gene family and presents a multifaceted characterization of a QTL-anchored candidate gene. These findings establish a genomic and molecular framework for further functional investigations of citrus-Alternaria interactions.
High-nighttime-temperature (HNT) poses a major challenge to tomato (Solanum lycopersicum L.) growth and productivity. To elucidate the molecular basis of HNT responses, this study systematically examined the morphological and transcriptomic changes in tomato seedlings under prolonged HNT stress. We observed that HNT suppressed plant growth and chlorophyll content while triggering H2O2 accumulation in new leaves; concurrently, it promoted thermomorphogenesis-related adaptations like reduced leaf angles and lower leaf trichome density, traits potentially facilitating heat dissipation. Transcriptome profiling identified 4,551 differentially expressed genes (DEGs), comprising 2,104 up-regulated and 2,447 down-regulated genes. Functional enrichment analysis revealed that up-regulated DEGs were primarily involved in glycosyl transfer, flavonoid biosynthesis, mismatch repair, and protein processing, whereas down-regulated DEGs were enriched in photosynthesis, metabolic, and immune signaling. These changes suggest a strategic trade-off, with down-regulated photosynthetic and metabolic activities potentially enabling the reallocation of resources toward stress resilience mechanisms. As a central heat shock response (HSR) mechanism, the SlHSPs-SlHSFs system responded to HNT, with 10-day stress inducing distinct expression patterns of SlHSP70/90 genes alongside concurrent suppression of SlHSFs. qPCR analysis unveiled a transcriptional shift in SlHSFs from an initial shock phase, marked by pronounced expression changes at 1-day HNT, to a sustained acclimation phase. Prolonged HNT also triggered gene-specific expression changes in the unfolded protein response (UPR) pathway, as well as in genes involved in ROS homeostasis and hormone signaling. In addition, it increased alternative splicing in genes associated with antioxidant defense, DNA repair, and protein processing. Collectively, these transcriptomic alterations reflect a systemic reprogramming that prioritizes energy conservation, redox homeostasis, and macromolecular stability to support nocturnal heat acclimation. Our findings provide novel insights into tomato adaptation to HNT and offer valuable genetic resources and a theoretical foundation for breeding HNT-resilient tomato varieties.
Meicha (Ampelopsis grossedentata) is a specialty Chinese herbal tea rich in flavonoids but lacks pleasant aromas. In this study, a novel process combining high-temperature re-roasting with mixed-culture fermentation using Eurotium cristatum produced Meicha with a distinctive composite aroma of "intense fungal-flowery, mellow-roasted, and harmonious sweet-fruity" notes, achieving optimal quality. HS-SPME/GC-MS and chemometrics identified 90 volatile compounds; high-temperature treatment introduced key aroma components such as (2E,4E)-2,4-octadienal and β-ionone, among which 21 compounds had odor activity values (OAV) ≥ 1. Dihydroactinidiolide reached 406.97 ng/g in the RMF sample, while β-ionone exhibited an OAV of 35,455.72 in RL1, confirming both as core aroma contributors. Molecular docking revealed that OR1A1 is the primary receptor for these odorants, with binding energies ranging from -8.0 to -4.8 kcal/mol, stabilized by hydrogen bonds with ASN155/HIS159 and hydrophobic interactions with TYR258/PHE206. This study is the first to demonstrate synergistic aroma improvement, offering a pathway for high-aroma Meicha products.
Corymbia citriodora wood holds extensive application value; however, due to the cross-pollination nature of C. citriodora and the significant genetic variation among offspring, a phenomenon is observed in plantations where trees with the same parental lineage exhibit varying diameter at breast height (DBH). In this study, we hypothesized that the observed DBH variation reflects two divergent adaptation strategies under winter conditions: smaller trees may exhibit heightened cold sensitivity, activating stress responses and entering early dormancy, whereas larger trees may sustain cambial activity through coordinated regulation of cell-cycle genes and carbohydrate metabolism. Metabolomics showed large trees enriched in phenolic compounds like picroside I and orientin. Transcriptomics revealed their genes were enriched in cell cycle and phenylalanine/tyrosine metabolism pathways, whereas small trees were enriched in abscisic acid (ABA) pathways. Integrated analysis revealed three patterns of transcript-metabolite coordination: (i) concordant upregulation (e.g., shikimate dehydrogenase (SDH)-shikimic acid), (ii) discordant regulation suggesting post-transcriptional control (raffinose accumulation without raffinose synthase (RFS) upregulation in small trees), and (iii) pathway-level flux redirection (phenylpropanoid pathway). Systematically, during winter, small trees exhibited stress-sensitive signatures, characterized by 9-cis-epoxycarotenoid dioxygenase (NCED), pyrabactin resistance/pyrabactin resistance-like (PYR/PYL), ABA-responsive element binding factor (ABF) upregulation, accumulation of raffinose, and transcriptional shift toward lignification (cinnamyl-alcohol dehydrogenase (CAD), peroxidase upregulation). Conversely, large trees showed molecular profiles indicative of stronger adaptability, with transcriptional signatures consistent with continued cell division (E2F transcription factor 3 (E2F3), mini-chromosome maintenance (MCM2/4/5/6) upregulation), cytoskeletal organization (kinesin KIN12B), and active carbohydrate metabolism (sucrose synthase (SUS), trehalose-6-phosphate phosphatase (TPP), alpha-amylase (AMY) upregulation), accumulating cinnamate and shikimic acid. This study advances understanding of tree growth variation by demonstrating that winter conditions reveal divergent adaptation strategies linked to DBH. The key conceptual advance is the integration of stress signaling, carbon metabolism, and cell-wall regulation into a unified framework where differential dormancy timing explains within-family growth variation. Large trees maintain a permissive growth state through coordinated upregulation of cell-cycle, cytoskeletal, and biosynthetic genes, while small trees exhibit coordinated stress responses that accelerate dormancy. These findings provide species-specific targets for functional validation-including E2F3, KIN12B, and NCED-and suggest that breeding for sustained winter cambial activity could enhance biomass production in subtropical plantations.
Melon (Cucumis melo L.) is an important economic crop, yet its cultivation relies heavily on manual pruning to regulate branching, which limits melon industrialization. Branching originates from axillary bud development, a process regulated by polar auxin transport, in which ABCB proteins serve as key auxin transporters. However, systematic identification of the ABCB gene family in melon and the functional roles of its members in axillary bud development have not been systematically elucidated. We performed a genome-wide identification of the ABCB gene family from the latest melon genome using bioinformatics approaches. We systematically analyzed the physicochemical properties and other characteristics of the identified CmABCB genes. Additionally, RNA sequencing (RNA-seq) and qRT-PCR were employed to investigate the expression patterns of these genes in axillary buds under IAA treatment. Through this genome-wide identification, we identified a total of 39 CmABCB genes in the melon genome. Phylogenetic analysis classified them into five subgroups, with Group I being unique to melon. Collinearity analysis revealed a close evolutionary relationship between melon and cucumber. Expression profiling revealed that several genes responded specifically to IAA treatment. Notably, CmABCB14, CmABCB20, and CmABCB21 exhibited a statistically significant positive correlation between their expression levels and IAA concentration. Collectively, these findings suggest that CmABCB14, CmABCB20, and CmABCB21 may function as auxin efflux carriers that suppress axillary bud growth. This study therefore provides a theoretical basis for understanding the molecular mechanisms underlying branching regulation in melon and offers a valuable framework for the precise improvement of plant architecture and the reduction of production costs through molecular breeding.
Methylmercury (MeHg) is a potent environmental toxicant that frequently coexists with other heavy metals, raising concerns about combined toxic effects. Increasing evidence indicates that co-exposure to multiple metals can lead to synergistic or greater-than-additive effects; however, the molecular mechanisms underlying such interactions remain poorly understood. Among the tested metals, only co-exposure with Cd markedly enhanced MeHg cytotoxicity. Here, our objective was to evaluate the impact of MeHg co-exposure on cytotoxicity of various heavy metals in HeLa cells. We used cell viability assays, western blot analysis, and reverse-transcription-quantitative polymerase chain reactions to determine toxicity. Co-treatment with MeHg significantly reduced cell viability compared with that of Cd alone. Mechanistically, MeHg suppressed nuclear factor erythroid 2-related factor 2 (NRF2) expression more strongly at earlier time points than Cd alone, thereby impairing antioxidant and detoxification responses. This suppression was accompanied by increased intracellular mercury (Hg) retention, leading to enhanced cytotoxicity. Our results provide a mechanistic basis for metal-metal interactions and highlight the importance of considering co-exposure scenarios in environmental risk assessment.