Search Results (1,597)

Xylaria karsticola NBIMCC 9097 is a recently described and rare fungicolous species originating from Bulgaria. Understanding its growth behavior and bioactive potential is essential for evaluating its biotechnological and pharmaceutical relevance. In the presented study, we model the in vitro growth kinetics of X. karsticola mycelium under submerged cultivation and assess its antimicrobial activity. Optimization of MCM and MYB media markedly increased biomass yields to 20.11 and 23.25 g/dm³, respectively, compared with non-optimized media (9.9 ± 0.21 and 10.8 ± 0.28 g/dm³). The maximum specific growth rate was higher in the MCM (0.803 ± 0.004 h⁻¹) in comparison with the MYB medium (0.711 ± 0.003 h⁻¹); however, the MYB medium supported greater biomass accumulation and more efficient substrate utilization, reflected by a higher utilization coefficient (0.9900 ± 0.001 versus 0.9644 ± 0.005). The antimicrobial activity was evaluated using agar disk diffusion and minimum inhibitory concentration assays against Gram-positive and Gram-negative bacteria and yeasts. Hexane and ethyl acetate extracts were most effective against Pseudomonas aeruginosa ATCC 9027 (MIC 0.067 and 0.059 mg/cm³), while notable anti-yeast activity was observed, particularly against Wickerhamomyces anomalus, Saccharomycodes ludwigii, and Pichia membranifaciens. The lowest MIC (0.02 mg/cm³) was recorded for the water biomass extract against S. ludwigii indicating potent antimicrobial activity against the tested microorganism. These findings identify X. karsticola as a potential source of antimicrobial metabolites and provide a strong motivation for comprehensive metabolomic profiling and systematic optimization of its cultivation. Full article

R2R3-MYB and bHLH transcription factors (TFs) are key regulators of floral secondary metabolism and epidermal development in flowering plants. Orchids exhibit remarkable floral diversity, which is critical for pollination success and ornamental value, yet the evolutionary and functional diversification of these TF families within the genus remains largely unexplored. Here, we conducted a comprehensive pan-genome dissection of R2R3-MYB and bHLH TF families across 18 Dendrobium species, integrating orthologs assignment, phylogenetics, duplication profiling, cis-regulatory annotation, and tissue-specific expression analysis. We identified 3074 R2R3-MYB and 2282 bHLH genes, classified into 69 and 61 orthologous gene groups (OGGs), respectively. Core OGGs accounted for two-thirds of both families, indicating strong evolutionary conservation, whereas variable OGGs reflected lineage-specific diversification. Phylogenetic analyses resolved R2R3-MYBs into 24 canonical subfamilies and revealed conserved heterogeneous expansion patterns in bHLH subfamilies. Promoter architectures of R2R3-MYB genes were enriched in hormone-, stress-, and light-responsive elements, whereas bHLH promoters were dominated by development-related motifs. Tissue-specific expression profiling in Dendrobium ‘Chao Praya Smile’ showed that floral bud-enriched genes were associated with flavonoid/anthocyanin biosynthesis, whereas root-enriched genes were linked to stress and hormone responses. Integration of pan-genomics and transcriptomics highlighted evolutionary trajectory and functional divergence between core and variable gene sets within Dendrobium. Our study establishes a comprehensive, genus-wide framework for understanding the evolutionary and functional characteristics of MYB–bHLH regulatory networks in Dendrobium. These findings provide valuable genetic resources and key candidate targets for functional characterization and molecular breeding, with important implications for genetic improvement of reproductive traits, floral quality, stress resistance, and ornamental and agronomic value in orchids. Full article

Walnut is valued for being rich in nutrients and polyphenols, which are key bioactive metabolites; however, a comprehensive and dynamic assessment of metabolites in the husk and pellicle is still lacking. In this study, multi-omics approaches combining untargeted metabolomics and transcriptome analysis were conducted to systematically characterize the differential metabolite profile and regulatory networks in walnut husk and pellicle. Metabolomic profiling revealed a clear divergence in polyphenol compositions between the husk and the pellicle; the husk was predominantly enriched in nine phenolic acid compounds, whereas the pellicle accumulated eleven flavonoid compounds. Through co-expression network analysis, a transcription factor, JrMYB8, was identified and shown to act as a specific inhibitor and regulator of polyphenol biosynthesis. Functional characterization demonstrated that JrMYB8 overexpression significantly reduced the accumulation of the total phenol content (TPC) and the total flavonoid content (TFC) by directly repressing the expression of JrC4H. These findings not only provide a molecular target for manipulating polyphenol content in walnut tissues but also offer a target for improving flavor in walnut breeding. Full article

Drought stress is a major limiting factor for canola production in arid and semi-arid regions, particularly during seed germination, seedling and flowering stages. In this study, we evaluated drought responses of doubled haploid (DH) lines derived from interspecific hybrids of B. napus × B. rapa and their parental cultivars under simulated (PEG-6000) and soil-based drought conditions. Drought stress significantly reduced germination, growth, and physiological performance in all genotypes; however, DH lines consistently exhibited superior tolerance. Under PEG-induced osmotic stress, DH lines maintained higher germination rates, root elongation, and relative water content compared with parental genotypes. During seedling and flowering stages drought, DH lines showed lower accumulation of hydrogen peroxide and malondialdehyde, alongside markedly higher antioxidant enzyme activities (CAT and POD) and improved photosynthetic efficiency (Fv/Fm). Gene expression analysis revealed strong induction of drought-responsive genes, including WRKY28, MYB, LTP, WSP, metallothionein, and protein kinase family genes, particularly in DH lines at prolonged stress exposure. Multivariate analyses (PCA and correlation) confirmed a close association between enhanced antioxidant capacity, transcriptional activation, and drought tolerance traits. Overall, our results demonstrate that homozygous doubled haploid lines derived from distant hybridization between B. napus and B. rapa exhibit enhanced drought tolerance at both early and reproductive stages. These genotypes represent valuable genetic resources for breeding drought-tolerance canola cultivars. Full article

MYB transcription factors (TFs) are crucial for plant growth, development, and response to abiotic stress. However, their exact functions in abiotic stress responses in rapeseed remain largely unexplored. In this study, we identified and characterized BnaMYB73, a member of the R2R3-MYB subfamily, and investigated its role in abiotic stress tolerance. The transcription level of BnaMYB73 was significantly upregulated in response to salt and osmotic stress. Transgenic Arabidopsis thaliana lines expressing BnaMYB73 displayed significantly enhanced tolerance to salt and osmotic stress, while showing no phenotypic differences in growth compared with wild-type (WT) plants under normal conditions. Physiological analyses revealed that the BnaMYB73-expressing plants accumulated higher proline levels, exhibited elevated superoxide dismutase (SOD) and peroxidase (POD) activities, and reduced malondialdehyde (MDA) content under stress conditions. Moreover, the BnaMYB73-expressing plants significantly upregulated key stress-responsive genes, including AtRD29B, AtDREB2A, AtRAB18, AtP5CS1, AtSOS1 and AtCAT1. Collectively, these findings establish BnaMYB73 functions as a stress-responsive transcription factor that enhances abiotic stress tolerance and provide a promising target for breeding stress-resilient rapeseed cultivars. Full article

Longan (Dimocarpus longan Lour.) is highly sensitive to low temperature, which severely restricts its cultivation and industrial development. MYB transcription factors serve as key regulators in plant responses to cold stress. In this study, an R2R3-MYB gene DlMYB108 was cloned from ‘Shixia’ longan. Sequence analysis showed that DlMYB108 contains two typical MYB repeats and shares high homology with cold-responsive MYB108 proteins from other plants. Expression pattern analysis revealed that DlMYB108 is highly expressed in young leaves, which are more sensitive to cold stress, and is significantly induced by low-temperature treatment. Subcellular localization and transcriptional activation assays confirmed that DlMYB108 is a nuclear-localized transcriptional activator. Yeast one-hybrid and dual-luciferase assays demonstrated that DlMYB108 specifically binds to the promoters of DlCBF2 and DlCBF3 and activates their transcription. Heterologous expression of DlMYB108 in Arabidopsis significantly enhanced cold tolerance, accompanied by reduced ion leakage, malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation, as well as upregulated expression of CBF and cold-responsive genes. Collectively, DlMYB108 positively regulates longan cold tolerance through activating DlCBF2 and DlCBF3 expression, providing a valuable candidate gene for cold-tolerant longan breeding. Full article

Lupinus angustifolius is an important leguminous ornamental species, but its productivity is often compromised by alkaline soil stress. GsEXPA8, an expansin gene identified in wild soybean (Glycine soja), has been implicated in alkali stress tolerance. In this study, we examined how heterologous expression of GsEXPA8 in lupinus affects its biochemical, molecular, and rhizospheric responses to alkali stress. Under NaHCO₃-induced alkaline conditions, transgenic lines overexpressing GsEXPA8 displayed improved leaf vigor, greater root biomass and length, elevated activities of antioxidant enzymes (CAT and POD), increased proline accumulation, and reduced malondialdehyde levels compared to the wild type. Expression analysis revealed time-dependent up-regulation of several alkali-responsive genes (LaSOS1, LaNCED3, LaMYB39, LaNAC56, LaNHX6, and LaP5CS). Moreover, the rhizosphere microbial community was significantly restructured, with a marked increase in beneficial microbial taxa such as Pseudomonas and Lysobacter. We also found that the endogenous lupinus homolog LaEXPA8 is alkali-inducible. Overexpression of LaEXPA8 similarly enhanced alkaline tolerance, whereas CRISPR/Cas9 knockout lines showed no clear phenotypic alteration, suggesting potential functional redundancy within the expansin family. Notably, LaEXPA8 and GsEXPA8 differed in their temporal regulation of downstream genes, indicating both conserved and distinct regulatory roles. Our results demonstrate that GsEXPA8 improves alkali tolerance in lupinus through integrated mechanisms: promoting root growth, enhancing antioxidant and osmotic adjustment capacity, dynamically modulating stress-related gene expression, and enriching beneficial rhizosphere microbiota. This work provides the critical report of modifying alkali tolerance by manipulating an expansin gene alongside the associated rhizosphere microbiome, offering a combined strategy for breeding stress-resistant ornamentals. Full article

Salivary adenoid cystic carcinoma (ACC) is a highly aggressive salivary gland malignancy characterized by infiltrative growth patterns that hinder complete resection. Lacking effective chemotherapy, recurrent or metastatic ACC remains clinically incurable. This research aimed to develop an efficient culture system for ACC organoids, which can preserve tumor heterogeneity and establish a reliable drug screening platform. Under our optimized culture conditions, ACC organoids grew rapidly and successfully recapitulated three characteristic histopathological patterns. Whole-genome sequencing (WGS) further confirmed they mirrored the genomic features of their parental tumors, including significantly mutated genes, non-coding regulatory region mutations, copy number variation, and minor allele frequency. RNA sequencing confirmed that ACC organoids recapitulated the MYB-NFIB fusion gene. At the protein level, these organoids contained multiple cellular components, including epithelial cells, mesenchymal cells, K7+ duct cells, a-SMA+ myoepithelial cells, K5+ basement membrane cells, and CD44+ tumor stem cells, with proper spatial distribution patterns. With an 88% success rate, the first ACC organoid platform, incorporating normal salivary gland (SG) organoids as toxicity controls, enabled high-throughput drug testing within two weeks. In conclusion, we developed an efficient culture system for ACC organoids that can preserve tumor heterogeneity and establish a reliable drug screening platform for mechanistic studies and personalized precision therapy research. Full article

Cibotium barometz (L.) J. Sm., a medicinally significant fern in traditional Chinese medicine, is little explored at the genomic level regarding its bioactive compounds. Using an integrated approach combining Illumina and PacBio sequencing technologies, we profiled its root, rachis, and pinna transcriptomes, identifying 12,718, 21,341, and 11,441 unigenes, respectively. Our analysis systematically characterized the transcriptional features of transcription factors (TFs), simple sequence repeats (SSRs), long non-coding RNAs (lncRNAs), and differentially expressed genes (DEGs). Enrichment analyses highlighted the roles of highly expressed unigenes in secondary metabolism. Seventeen key enzymes involved in polysaccharide biosynthesis showed tissue-specific expression patterns. Notably, total polysaccharide content correlated positively with UDP-arabinose 4-epimerase (UXE) expression but negatively with phosphoglucomutase (PGM) and 3,5-epimerase/4-reductase (UER1). Flavonoid accumulation inversely correlated with chalcone synthase (CHS) expression. Two lignin pathways (H-lignin and G-lignin) were characterized, with phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and cinnamyl alcohol dehydrogenase (CAD) as key genes. The absence of ferulate-5-hydroxylase (F5H) explains the undetected S-lignin pathway. Regulatory network analysis revealed positive correlations between PAL expression and NAC72/NAC78/WRKY35 and C4H expression and WRKY65/WRKY69/WRKY71, while a negative correlation was revealed between flavonoid 3′,5′-hydroxylase (F3′5′H) and MYB3R4. This study provides comprehensive transcriptomic insights into C. barometz bioactive compound biosynthesis, serving as a foundation for mechanistic research. Full article

Boron (B) toxicity is one of the major abiotic stresses limiting wheat productivity in arid and semi-arid regions of the world. Thus, it is important to understand the molecular basis of tolerance in boron-tolerant wheat genetic resources for effective breeding. Wild emmer wheat is a valuable genetic resource for tolerance to multiple abiotic stresses; however, the molecular mechanisms behind boron toxicity tolerance in this species has not been sufficiently characterized. Here, we present the first RNA sequencing-based transcriptomic analysis of B toxicity response in a boron-tolerant Triticum dicoccoides genotype, PI362036. Shoot tissues exposed to high boron (10 mM B) for 7 days showed extensive transcriptional reprogramming with 2783 differentially expressed genes. Functional enrichment analyses showed that B toxicity significantly altered the genes associated with biosynthesis of secondary metabolites, metabolic pathways, ribosomal activity, carbon metabolism, RNA transport, photosynthesis–antenna proteins, and citrate cycle pathway. Several transcription factor families, including TIG, MYB, MYB-related families, NAC, C2H2-GATA, ARF, and AP2-EREBP families, showed significant differential regulation, emphasizing their regulatory roles in B stress adaptation. Collectively, this study provides the first comprehensive transcriptomic framework of boron toxicity tolerance in T. dicoccoides under short-term high boron exposure, identifying candidate genes and pathways that may be exploited for improving boron tolerance in cultivated wheat through targeted breeding strategies. Given that boron toxicity in agricultural systems primarily arises from excessive boron accumulation in soils and irrigation water, the identified pathways offer insight into early adaptive responses of shoot tissues to elevated boron availability. Full article

Salt stress is a major environmental constraint affecting plant growth and productivity. Crop wild relatives provide valuable genetic resources for stress tolerance, yet transcriptomic information for forest-derived wild species remains limited. In this study, we analyzed transcriptional responses of V. hirsuta, a crop wild relative (CWR) of legumes, after seven days of salt stress using de novo transcriptome sequencing. Seedlings were exposed to salt stress, and differentially expressed genes (DEGs) were identified between control (Vh_S0) and salt-treated (Vh_S7) plants using an FDR-adjusted threshold (q < 0.05). Gene Ontology and KEGG enrichment analyses revealed that salt-responsive DEGs were mainly involved in regulatory signaling, metabolic adjustment, redox-related processes, and macromolecular organization. Up- and down-regulated DEGs showed distinct yet overlapping enrichment patterns, indicating complex transcriptional reprogramming under salt stress. Transcription factor analysis identified bHLH, MYB, bZIP, NAC, and WRKY families as major regulators, with many families containing both up- and down-regulated members. Notably, genes associated with Na⁺/K⁺ homeostasis were consistently up-regulated and validated by qRT-PCR. These results suggest that continuous seven days salt stress adaptation in V. hirsuta involves coordinated regulation of signaling pathways, transcriptional networks, and transporter-mediated ion homeostasis, providing a valuable transcriptomic resource for crop wild relatives. Full article

Tea is a vital economic crop in China, with many anthocyanin-rich cultivars having been bred. Photoperiod is an important environmental factor that regulates anthocyanin production in plants. Nonetheless, the precise mechanisms by which photoperiod affects anthocyanin biosynthesis in tea plants remain unclear. In this study, the purple-leaf cultivar Camellia sinensis ‘Ziyan’ was exposed to three different photoperiods: 8 h/16 h (light/dark, short-day, SD), 14 h/10 h (light/dark, medium-day, MD), and 20 h/4 h (light/dark, long-day, LD). A comprehensive analytical approach, including transcriptomics, enzymology, and quantitative anthocyanin analysis, was used to uncover the molecular and biochemical processes regulating anthocyanin synthesis in purple-leaf tea plants grown under varying photoperiods. The results showed that the delphinidin, cyanidin, pelargonidin, and total anthocyanin contents in the long-day treatment were 178.10%, 92.37%, 50.40%, and 148.76% higher, respectively, than those in the short-day treatment. Under long-day conditions, all structural genes associated with anthocyanin synthesis were upregulated, and enzymatic activities related to anthocyanin synthesis were significantly increased. Furthermore, the regulatory genes (MYB1, MYB73, MYB111, MYB48, MYB75, MYB113, MYB5, MYB12, MYB5a, MYB5b, and WRKY41) were differentially expressed under short- and long-day treatments. These findings suggest that extended photoperiods activate the expression of structural genes through gene regulation and enhancement of enzymatic activity, thereby facilitating anthocyanin biosynthesis. This study provides novel insights into the photoperiodic regulation of anthocyanin biosynthesis in tea plants. Full article

Kiwiberry (Actinidia arguta) has been rapidly commercialized. However, fruits produced in northern growing regions predominantly have green peels, and the red/purple peel phenotypes remain relatively rare, which limits the discovery and utilization of red-peel germplasm. Peel reddening is primarily caused by the accumulation of anthocyanins, and R2R3-MYB transcription factors are key regulators of the flavonoid/anthocyanin biosynthetic pathway. However, the MYB transcription factor family in the genus Actinidia has been less studied, with few systematic analyses linked to color phenotypes. Therefore, we performed a genome-wide search for R2R3-MYB family members in A. arguta and characterized their physicochemical properties, phylogeny, chromosomal distribution, gene duplication events, and synteny relationships. Furthermore, RNA-Seq analysis, phylogenetic analysis, and gene expression patterns of the rare northern red-peel cultivar ‘Yanlong 1’ revealed that AaMYB1 and AaMYB36 are key candidate genes closely associated with anthocyanin biosynthesis in the fruit peel. Validation experiments revealed that both genes exhibited significantly higher expression during the coloration stage than during the green fruit stage, as well as significantly higher expression in the red-peel cultivar than in green-peel cultivars. Four key structural genes (UFGT, CHS, DFR, and ANS), especially, CHS, DFR, and ANS, displayed a similar pattern of upregulation. These correlative results suggest that AaMYB1 and AaMYB36 are candidate positive regulators of peel-specific anthocyanin accumulation. These results provide important targets for developing molecular markers and improving the red-peel trait in northern A. arguta through breeding. Full article

Background/Objectives: This study was based on the joint analysis of transcriptome and metabolome to explore the key genes and metabolic pathways of gardenia single flower petal number variation and to explore the possible mechanism of floral organ variation. Methods: Five, six, and seven petals of single-flower gardenia were selected as test materials for transcriptome and metabolome determination to excavate the key genes in regulating petal number in gardenia. Results: Metabolomic analysis identified triethylamine, succinic acid, succinylaldehyde, 2-phenylethanol, and o-xylene as the top five differentially expressed metabolites affecting petal number variation in gardenia. In the KEGG enrichment analysis, gardenia five, six, and seven DEGs were mainly enriched in amphetamine biosynthesis, the biosynthesis of plant secondary metabolites; transcriptome results showed that the identified differential transcription factors mainly come from NAC, ERF, C2H2, MYB, and MADS-box gene families; the expression of GjMADS50, GjMADS59, and GjERF28 changed with the increase in petal number. The commonality between gardenia five, six, and seven flowers exceeded the difference, and the expression pattern of MADS-box and ERF gene family members was the upregulation of GjERF28, GjERF39, and GjMADS67 and downregulation of GjMADS50, GjMADS59, and GjMADS60. Conclusions: We propose that ERF transcription factors may determine the initial number of petal primordia by mediating gibberellin biosynthesis or signaling, thereby coordinately regulating floral meristem activity and specific metabolic states. Full article

Drought stress significantly limits crop yield by disturbing plant water status and redox homeostasis, leading to oxidative stress and growth suppression. Anthocyanins, with their strong antioxidant properties, are closely linked to abiotic stress adaptation. The R2R3-MYB transcription factor SlANT1 promotes anthocyanin biosynthesis in tomato, yet its role in drought resistance remains poorly understood. This study explored the function of SlANT1 in tomato under drought conditions. SlANT1 expression was upregulated under both drought and high salinity. The overexpression of SlANT1 resulted in higher anthocyanin accumulation and reduced leaf and stem dimensions. Under drought, SlANT1-overexpression (SlANT1-OE) plants maintained a greater leaf relative water content, showed less negative water potential, wilted less, and recovered faster after rewatering. These plants also accumulated lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). While antioxidant enzyme activities were generally reduced, anthocyanin-dependent ROS scavenging was significantly enhanced. SlANT1 overexpression also modulated carbohydrate metabolism and aquaporin gene expression, elevating sucrose, fructose, glucose, and soluble protein while decreasing starch, thereby supporting osmotic adjustment. Notably, while stomata remained partially open in SlANT1-OE plants during drought, they exhibited reduced stomatal density, which likely compensated for the wider apertures and helped maintain favorable water status, while still sustaining higher photosynthetic rates and photosystem II integrity. These findings demonstrate that SlANT1 enhances drought tolerance through coordinated mechanisms involving anthocyanin-mediated antioxidant protection, improved water relations, and the reprogramming of carbohydrate and aquaporin pathways. SlANT1 thus represents a promising target for breeding drought-resilient, high-anthocyanin tomato varieties. Full article