Search Results (173)

Artemisinin, a sesquiterpene lactone produced by Artemisia annua, is synthesized and stored predominantly in glandular secretory trichomes (GSTs). Despite substantial advances in elucidating its biosynthetic pathway and transcriptional regulation, a key challenge remains: how developmental processes, hormone signaling, and metabolic pathways are coordinately integrated to overcome the trade-off between trichome density, metabolic flux, and vegetative biomass, which ultimately limits whole-plant yield. Recent studies have identified basic helix–loop–helix (bHLH) transcription factors (TFs) as central integrative hubs in this network. AabHLH113 functions as a convergence node linking jasmonic acid (JA) and abscisic acid (ABA) signaling to activate core biosynthetic genes. AaMYC3 bridges development and metabolism by promoting GST initiation via AaHD1 while enhancing pathway flux and cooperating with other bHLH factors to amplify amorpha-4,11-diene synthase (ADS) and artemisinic aldehyde delta-11(13) reductase (DBR2) expression. Extending this regulation to the whole-plant level, AaSPATULA coordinates GST formation with photosynthetic capacity, carbon assimilation, and biomass accumulation. Here, we propose a unified framework in which bHLH TFs integrate hormone signaling, trichome development, metabolic flux, and carbon allocation into a coherent regulatory system. We further discuss implications for next-generation metabolic engineering and highlight future directions, including multi-omics-guided, multi-target editing of regulatory hubs. This developmental–metabolic integration framework provides a conceptual basis for optimizing artemisinin production and improving high-value metabolite biosynthesis in other trichome-bearing plants. Full article

This study elucidated the molecular, morphological and anatomical mechanisms underlying differential cold tolerance between two cotton cultivars, cold-tolerant Xinluzhong 61 (C61) and cold-sensitive Tahe 2 (C2). Seedlings were subjected to 0 °C cold stress for 12 and 24 h, followed by comparative transcriptomic (RNA-Seq) and comprehensive anatomical analyses of cotyledons, true leaves and stems. Transcriptomic profiling identified 8834 and 14,664 differentially expressed genes (DEGs) in C2 and C61 at 12 h, and 14,399 and 16,791 DEGs at 24 h, respectively. KEGG enrichment revealed prominent involvement of phenylpropanoid biosynthesis, photosynthesis, and cutin/suberin/wax biosynthesis at 12 h, shifting to phagosome, cysteine and methionine metabolism at 24 h. Phenotypic and anatomical observations confirmed that C61 developed dense stem glandular trichomes absent in C2, maintained significantly greater leaf thickness, palisade tissue thickness and palisade-to-spongy ratio in true leaves after 24 h stress, and exhibited thicker stem xylem. These findings highlight core adaptive traits and provide valuable genetic targets for improving cold tolerance in cotton. Full article

Cannabinoid content can vary several-fold across Cannabis sativa L. cultivars that carry functional, closely related CBDA synthase (CBDAS) and THCA synthase (THCAS) alleles, a difference that coding-sequence variation among functional alleles does not fully explain. Structural and copy-number variation at the synthase loci, the functional or pseudogenised state of synthase alleles, and linkage at the B locus account for much of the qualitative drug-versus-hemp chemotype; however, these genetic factors do not fully explain the quantitative, several-fold variation in cannabinoid content among cultivars that carry functional, near-identical synthase alleles. Three independent lines of evidence now indicate that chromatin-level regulation contributes to this variation. H3K4me3 and H3K56ac co-occupy the promoters and gene bodies of THCAS, CBDAS, OLS, and OAC exclusively in glandular trichome tissue while H3K27me3 marks the identical loci in vegetative tissues, indicating that a Polycomb-to-Trithorax chromatin switch is associated with trichome-specific cannabinoid gene expression, potentially independently of transcription factor availability. Progressive DNA hypomethylation accumulates during micropropagation in a cultivar-specific manner, with promoter-region differentially methylated positions reaching up to 22% by twenty subcultures, identifying DNA methylation maintenance as a candidate determinant of epigenetic stability in clonally propagated material, although the functional consequences for cannabinoid pathway gene expression and yield remain to be quantitatively established. In Cannabis indica cell suspension cultures, UV irradiation increases genome-wide DNA methylation (detected by MSAP, which does not resolve locus-specific changes) and elevates CBDAS transcript levels approximately 4-fold relative to non-irradiated controls. This coupling of an environmentally triggered methylation change to cannabinoid pathway gene expression in the Cannabis genus is suggestive, but the genome-wide MSAP signal and the use of C. indica cell cultures mean the locus-specific methylation change at the CBDAS promoter remains to be demonstrated. These findings identify specific, experimentally documented chromatin states as candidate targets for dCas9-effector intervention, including the H3K27me3 repressive state at cannabinoid loci that could be addressed by dCas9-KDM6A and the propagation-induced CG hypomethylation that could be addressed by dCas9-DNMT3A; these editing strategies remain hypotheses that have not yet been tested in Cannabis. We synthesize functional evidence from Catharanthus roseus, Papaver somniferum, and Artemisia annua demonstrating that equivalent chromatin switches control secondary metabolite yield in medicinal plants, evaluate which dCas9-effector architectures are most appropriate for each Cannabis chromatin target, and identify the critical mechanistic gaps that must be closed before epigenome editing can be rationally deployed for cannabinoid yield enhancement in Cannabis. Full article

Dittrichia viscosa (L.) Greuter is a Mediterranean species widely recognized for its remarkable ecological plasticity and its rich repertoire of secondary metabolites, among which volatile organic compounds (VOCs) play a central role. This review provides an integrative synthesis of current knowledge on D. viscosa, with a primary focus on its VOCs, including their extraction techniques, chemotypic variability, and biological activities, while contextualizing these compounds within the species’ broader phytochemical and ecological framework. Available evidence indicates that VOC profiles are dominated by terpenoids, particularly oxygenated sesquiterpenes and monoterpenes. The composition of volatile fractions is strongly influenced by extraction methodology, plant organ, developmental stage, and geographic origin, resulting in pronounced chemotypic variability across Mediterranean populations. Beyond their direct bioactivity, VOCs are considered in their ecological context, particularly in relation to glandular trichome-mediated secretion, plant–insect interactions, and potential applications in integrated pest management. Non-volatile metabolites are also discussed to provide a comprehensive view of the species’ bioactive potential. Overall, D. viscosa emerges as a multifunctional species in which VOCs are a pivotal, though not isolated, component of a complex phytochemical system with promising applications in agriculture, pharmacology, and environmental management. While the convergence of multiple studies supports the biological potential of D. viscosa and its metabolites, particularly in vitro, the translation of these findings into in vivo efficacy and safety remains an important area for future research. This integrative perspective highlights the need for standardized analytical approaches and chemotype-aware studies to fully exploit the biological and biotechnological potential of this Mediterranean species. Full article

Efficient micropropagation systems are essential for the large-scale production of uniform and high-quality plant material in aromatic species. In this study, the effects of gibberellic acid (GA₃; 1.4, 2.8, and 5.6 $\mathsf{\mu }$M) and methyl jasmonate (MeJA; 2.2, 4.4, and 8.8 $\mathsf{\mu }$M) were evaluated on the in vitro performance of Artemisia pontica across two successive subcultures. Morphological, physiological, and biochemical parameters were assessed, and the most effective treatment was further investigated through scanning electron microscopy (SEM) to evaluate leaf trichome characteristics. GA₃ treatments significantly enhanced shoot growth, shoot number, and relative growth rate, with the strongest response observed at 2.8 $\mathsf{\mu }$M. This concentration also promoted higher chlorophyll content and antioxidant activity, indicating improved physiological status and metabolic performance of plantlets. In contrast, MeJA treatments, particularly at 8.8 $\mathsf{\mu }$M, reduced growth performance and pigment accumulation, suggesting a less favorable physiological status for micropropagation. Multivariate analysis (PCA and hierarchical clustering) revealed a clear separation among treatments, with GA₃ at 2.8 $\mathsf{\mu }$M associated with a coordinated increase in growth-related and antioxidant traits. SEM analysis showed that GA₃ influenced leaf epidermal structure, increasing the density of T-shaped, non-glandular trichomes and the diameter of glandular secreting trichomes, suggesting structural adjustments linked to metabolic activity. Overall, the results indicate that GA₃ at 2.8 $\mathsf{\mu }$M represents the most effective supplementation under the tested conditions, promoting a balanced improvement in shoot proliferation, physiological performance, antioxidant activity, and selected structural traits. Full article

Silene zawadskii Herbich is an endemic species restricted to the South-Eastern Carpathians, being found in Romania and Ukraine. The species is rare and protected in the two countries. The root system is deep, to facilitate water absorption, the basal leaves, arranged in a rosette, are leathery and glabrous. The stem presents numerous multicellular, uniseriate non-glandular trichomes, only in the upper part; they become caducous at the base. The small size of the plant, correlated with the very narrow xylem vessels, represents a way of increasing the resistance to physiological drought and preventing embolism in drier periods. Another particular feature of this species is the presence of numerous large calcium oxalate crystals (druses), both in the stem and especially in the leaves. The flowers are adapted to entomophilous pollination, showing structural traits that facilitate interactions with alpine pollinators, particularly under conditions of reduced insect diversity at high altitudes. These anatomical traits reflect its ecological specialization, making it a valuable indicator for assessing edaphic–climatic niche specificity and the functional connectivity of high-altitude ecological networks. Full article

Cannabis sativa glandular trichomes (CsGT) are the primary sites of cannabinoid biosynthesis. They consist of a metabolically active head and a structurally supportive stalk. While the biosynthetic role of the head is well established, understanding of the functional contribution of the stalk has lagged. Here, we performed an integrated proteomic and transcriptomic analysis of isolated CsGT head and stalk tissues to identify their distinct roles. While proteomic analysis found 35 proteins higher in the stalk compared to the head, the transcriptomic analyses suggest the true functionality of the stalk, with 6018 genes showing higher expression in this tissue. Marker gene analysis showed a predominantly epidermal signature for head cells, while stalk cells also showed signatures for vascular cell types. Congruently, the transcriptomic results showed genes with higher expression in the head associated with specialized secondary metabolite production and accumulation, while the stalk displayed enrichment for genes related to active growth, vascular, apoplastic and symplastic transport, as well as sugar and hormone signalling. These findings support a model in which the stalk is a complex epidermal tissue, highly distinct from the head, that facilitates metabolite transport, signalling, and precursor supply to the glandular head. This study provides the first multi-omics characterization of CsGT stalk function, identifying it as a key contributor to trichome productivity and a potential target for optimizing cannabinoid yield. Full article

Pruning residues from medicinal and aromatic plant cultivations represent an under-exploited biomass rich in bioactive metabolites. In this study, pruning by-products from Lavandula angustifolia Mill. ‘Essence Purple’ and Helichrysum italicum (Roth) G.Don were investigated as sources of essential oils (EOs) within a circular economy perspective. Micromorphological analyses confirmed the presence of secretory glandular trichomes in the residual biomass. EOs were obtained by steam distillation (0.33% and 0.15% yield for lavender and helichrysum, respectively) and chemically characterized by GC-FID and GC-MS. A total of 51 and 55 compounds were identified, accounting for 99.68% and 99.57% of the total composition. The main constituents were τ-cadinol (23.09%) and linalyl acetate (14.07%) in lavender EO and γ-curcumene (15.47%) and eudesm-4(14)-en-11-ol (10.71%) in helichrysum EO. Pruning-derived EOs showed a higher sesquiterpene content than those from conventional plant organs, indicating a compositional shift. Phytotoxic assays on Hordeum vulgare, Raphanus sativus, Lolium multiflorum, and Sinapis alba revealed concentration-dependent effects, with a stronger inhibition of radicle elongation than seed germination. These concentrations should be interpreted as indicative of intrinsic phytotoxic potential under controlled conditions. Ecotoxicological tests showed no significant reduction in viability in Artemia salina, whereas concentration- and time-dependent immobilization was observed in Daphnia magna, highlighting species-specific sensitivity, likely related to differences in the uptake and membrane interactions of lipophilic compounds. These findings highlight pruning residues as a promising biomass for the recovery of bioactive phytocomplexes with potential applications in sustainable weed management, although further studies under agronomically relevant conditions and comprehensive environmental assessments are required to validate their practical applicability. Full article

The effects of progressive drought stress were examined in four economically important plant species belonging to the Lamiaceae family: catnip (Nepeta cataria L.), lavender (Lavandula angustifolia Mill.), holy basil (Ocimum tenuiflorum L.), and perilla mint (Perilla frutescens (L.) Britton). Plants were grown in a controlled pot experiment under three soil water capacity levels: 70% (control), 50% (moderate stress), and 30% (severe stress), and the drought stress lasted for 30 days. The study evaluated a comprehensive set of leaf micromorphological parameters, including the density and diameter of glandular trichomes, stomatal density and size, and the thickness of the lamina, mesophyll, epidermis, cuticle, and parenchymal layers. In addition, essential oil (EO) content, total flavonoid content (TFC), and elemental composition were analyzed. Drought responses were strongly species-specific. O. tenuiflorum, P. frutescens, and N. cataria showed high sensitivity characterized by reduced biomass and thinning of leaf tissues. These changes were accompanied by typical xeromorphic adaptations, such as increased stomatal and glandular trichome density, and reduced stomatal size. L. angustifolia exhibited pronounced cuticle thickening, suggesting an effective structural mechanism to minimize water loss. Secondary metabolism also responded differently among species. In some cases, drought shifted metabolic allocation toward flavonoid accumulation at the expense of essential oils, whereas in others, moderate stress promoted the co-accumulation of both compounds. These patterns indicate distinct adaptive strategies linking anatomical plasticity with metabolic regulation. Overall, moderate drought supported adaptive responses, while severe water limitation impaired growth and metabolic production. From a practical perspective, maintaining moderate soil water availability appears critical to optimize both plant performance and the accumulation of valuable secondary metabolites in Lamiaceae species. Full article

Glandular trichomes (GTs) are epidermal outgrowths that function as “natural cell factories” for the synthesis of specialized metabolites. Beyond their traditional understanding, GTs on cucumber fruits can form an undesirable trait known as bloom, which negatively affects market value. However, the secretory process, metabolite profiles, and genetic regulation underlying GT development in cucumber remain largely unclear. In this study, we employed scanning electron microscopy (SEM), transmission electron microscopy (TEM), histochemical staining, multi-omics analyses, and liquid chromatography–mass spectrometry (LC-MS) to systematically investigate GT development. The secretory process was classified into four distinct stages via SEM observations: morphogenesis, active metabolism, head sunken, and metabolite release. TEM revealed progressive ultrastructural changes, including increased organelle abundance and expansion of the periplasmic space, which facilitate metabolite transport and release. This process occurs through an autonomous mechanism involving osmiophilic substances and eventual cell rupture. LC-MS analysis identified 744 metabolites belonging to 11 classes, with phenylpropanoids/polyketides—particularly flavonoids—being the most abundant. While metabolite classes are conserved between European greenhouse and North China ecotypes, specific metabolite contents vary significantly. Multi-transcriptome analysis identified 60 candidate genes associated with GT development. Among these, CsaV4_3G003418 was functionally validated through virus-induced gene silencing (VIGS) to be involved in early GT development. Collectively, this work elucidates the secretory mechanism and metabolic characteristics of cucumber GTs, providing a foundation for future functional studies and biotechnological applications of secondary metabolites. Full article

Bayberry (Morella rubra Lour.; syn. Myrica rubra (Lour.) Siebold & Zucc.) leaves are rich in bioactive compounds but remain underutilized. This study investigated the optimal harvest stage and processing methods to develop high-quality functional powder. We first compared three growth stages: red buds (RB), new leaves (NL), and old leaves (OL). RB exhibited the highest antioxidant capacity and unique volatile profile; however, NL was selected for processing optimization due to the balance between quality and biomass availability. Subsequently, NL was subjected to freeze-drying (FD), mechanical drying (MD), steaming followed by MD (S-MD), and shade drying (SD). Results showed that FD preserved the vibrant green color, glandular trichome structure, ascorbic acid, and fresh volatiles (monoterpenes). Conversely, thermal drying (MD and S-MD) disrupted cellular barriers, which facilitated the extraction of minerals and robust polyphenols like myricitrin, yielding the highest extraction of flavonoids and corresponding antioxidant activity, measured by hydrophilic oxygen radical absorbance capacity (H-ORAC), in hot water extracts than FD. SD significantly degraded quality due to prolonged enzymatic oxidation. While FD is ideal for preserving aesthetics and heat-sensitive nutrients, low-cost MD and S-MD are recommended for producing antioxidant-rich powders for functional food applications where extraction efficiency is prioritized. Full article

Essential oils (EOs) of Mentha spicata var. crispa (Benth.) Danert and M. × piperita var. citrata (Ehrh.) Briq. and EO components are widely used in medicine, pharmaceuticals, cosmetics, hygiene products, the food industry, and other fields, and have a high commercial value. The variety Mentha spicata var. crispa is also used as an ornamental plant due to its distinctive curled leaves. Studying the influence of growing conditions and harvest timing on EO yield and the major compound concentrations is one of the key research directions for Mentha species, aimed at the ascertainment of the ways of increasing EO production and quality. Gas chromatography analysis of the component composition of EOs from leaves of Mentha spicata var. crispa “Kurchavaya” (MscK) showed that it remained stable both in July and September, with carvone predominating (81% and 85%, respectively). In contrast, the EO composition from M. × piperita var. citrata “Apelsinovaya” (MpcA) leaves changed in the course of the vegetation period. In July, menthofuran dominated (30%), while in September, linalool and its acetate were predominant (34% and 47%, respectively), which was typical for this chemotype. At the same time, the content of EOs and the density of glandular trichomes (GTs) (the OE storage sites) in MscK were higher in July and decreased by September, whereas in MpcA, both EO content and the number of GTs increased from July to September. These changes may have been caused by temperature fluctuations. Thus, MscK proved to be more resistant to environmental factors than MpcA. Full article

Plants are naturally exposed to various biotic stresses, including pathogen attacks and insect herbivory, which activate distinct signaling pathways as part of their defense responses. Inoculation with beneficial microorganisms, such as plant growth-promoting rhizobacteria (PGPR), can trigger induced systemic resistance (ISR) in plants, a defense response that resembles the one activated by herbivore attack in terms of signaling pathways and physiological effects. However, these interactions have typically been studied independently, limiting our understanding of their combined effects. In this study, we examined the effects of aphid (Acyrthosiphon pisum) herbivory on Ocimum basilicum plants and assessed how these responses are modulated when the plants are inoculated with the PGPR strain Bacillus amyloliquefaciens GB03, with a particular focus on biochemical and structural defense mechanisms. Aphid herbivory significantly increased total essential oil (EO) content and volatile organic compound (VOC) emission and induced a greater density of glandular trichomes while also modifying the phytohormone profile. In contrast, total phenolic content remained unchanged. When aphid herbivory occurred on GB03-inoculated plants, the effects on defense-related parameters became more pronounced. EO and eugenol contents were further increased compared with inoculated controls, jasmonates remained comparable to levels induced by either factor alone, and SA levels nearly doubled relative to aphid-infested plants. Feeding assays revealed that aphids preferred inoculated plants over controls, a response that may be explained by the increased emission of eugenol in inoculated basil. These results demonstrate that GB03 inoculation modifies several defenses-related responses in O. basilicum upon aphid herbivory, including by hormonal signaling, specialized metabolites accumulation, and structural barriers such as glandular trichomes. These findings suggest that PGPR may contribute to modulating plant responses to herbivory under certain conditions, highlighting their context-dependent influence within plant–microbe–insect interactions. Full article

Seed processing effects induced by two types of cold plasma, CP (low-pressure plasma, LCP; dielectric barrier discharge plasma, DBD), and vacuum (V) treatments were compared by estimating changes in the emergence and growth of lavender seedlings, the density of leaf trichomes, and the biochemical composition of leaf extracts, including the content of photosynthetic pigments, TPC, antioxidant activity, and the amounts of two hydroxycinnamic acids associated with antioxidant activity—chlorogenic and rosmarinic acid. DBD treatment for 3 min stimulated the emergence and growth of seedlings but induced negative or neutral effects on biochemical parameters. All treatments, except DBD3, increased the density of glandular trichomes in leaves. Short-term treatments with LCP (0.5 min), DBD (2 min), and V (2 min) increased the total phenolic compound (TPC) content by 15–25%, and the first two treatments enhanced antioxidant activity (21–32%). HPLC analysis revealed that V (2 min) treatment was the most effective, increasing the content of chlorogenic (49%) and rosmarinic (14%) acid. LCP (1 min) and DBD (2 min) treatments increased chlorogenic acid content by 9% and 26%, respectively. The obtained results support the potential of pre-sowing seed treatments with CP and vacuum to produce raw lavender material enriched by biologically active compounds for pharmaceutical and nutraceutical applications. Full article

Cannabis is usually dioecious, with male and female flowers on separate plants. Cultivators prioritize the use of female plants because their flowers contain a higher density of glandular trichomes, the primary source of cannabinoids, compared to male flowers. Feminized seeds, which give rise exclusively to female plants, are highly valued in the cannabis industry. These seeds are produced by crossing a natural female plant with another female plant that has been masculinized to generate pollen. Masculinization is achieved by inhibiting ethylene and/or applying gibberellins prior to flower initiation in female plants. Currently, silver thiosulfate (STS) is the most common treatment used in the cannabis industry, though environmental concerns arise from silver applications. This study compared STS with three other ethylene-inhibiting agents: aminoethoxyvinylglycine (AVG), cobalt nitrate (CBN), and 1-methylcyclopropene (1-MCP). Some STS and CBN treatments also included gibberellic acid as a synergist. STS-treated plants displayed the most effective masculinization and pollen dispersal, compared to plants treated with AVG. Only STS and AVG generated sufficient pollen for collection. This pollen was initially tested for germination potential and subsequently stored for up to five weeks at 22.2 °C, 7.2 °C, or 1.1 °C.Germination rates ranged from 2.2% to 5.8%, underscoring the influence of storage conditions and highlighting the need to refine preservation methods to enhance agricultural viability. Pollen from plants treated with AVG remained viable for three weeks at 1.1 °C, although there were concerns about a high risk of phytotoxicity. STS-treated pollen also remained viable for three weeks at the same temperature. Neither CBN nor 1-MCP treatments were effective in inducing masculinization. No clear synergistic effect of gibberellic acid combined with STS or AVG was observed; however, growth stunting led to increased mortality. Due to pollen viability and phytotoxicity problems with AVG, STS remains the best treatment to masculinize female cannabis plants when breeding for feminized seeds. Full article