Leaf Epidermis Research Articles

Pathways in Biomimicry to Enhance Solar Technology Capabilities

Efficiency, longevity, and cost-effectiveness in current solar modules are compromised in pursuit of best balancing one another. This report explores the potential of enhancing solar cell practicability through biomimicry. Like solar cells, biological organisms absorb heat during photosynthesis, positioning nature as an inherent source of inspiration to tackle current technological challenges. Significant improvements have been achieved by mimicking structures such as the leaf epidermis for multidirectional light capture, cell membranes for protective encapsulation, and butterfly wings for enhanced light absorption and reflection. For instance, incorporating a BT layer for thermoregulation mimics plant transpiration, enhancing cooling efficiency. Additionally, hierarchical structures inspired by leaf geometry increases angular robustness in both dye-sensitized solar cells and passive emitter and rear cells, and lipid biomolecule interactions shelter halide perovskites from environmental degradation. The nanostructures of butterfly wings also show promise in supporting thin film PVs to overcome conversion inefficiency. Lastly, the reflective properties of butterfly wings have led to advancements in solar concentrators, improving power-to-weight ratios. These examples highlight the untapped potential of biomimicry in furthering the viability and deployment of solar technologies.

Wheat Topoisomerase VI Positively Regulates the Biosynthesis of Cuticular Wax and Cutin.

Lipophilic cuticles mainly composed of wax mixtures and cutin matrices seal the plant epidermis and control plant development and environmental adaptation. Although cuticle-associated traits have been selected in the breeding of agronomically important cereal bread wheat, the biosynthesis of wheat cuticular wax and cutin remains poorly understood. Herein, wheat topoisomerase VI was characterized as an essential activator of cuticular wax and cutin biosynthesis. Knock-down of wheat TaTOP6A, TaTOP6B, TaRHL1, or TaBIN4 gene encoding component of topoisomerase VI resulted in decreased loads of leaf cuticular wax and cutin, as well as increased leaf cuticle permeability. Moreover, TaCYP86A2 was identified as a key component of the wheat cutin biosynthetic machinery. Reduction of wheat TaCYP86A2 expression led to decreased cutin accumulation and enhanced cuticle permeability. In addition, TaTOP6A, TaTOP6B, TaRHL1, or TaBIN4 was shown to enrich at the promoter regions of the wax biosynthesis gene TaKCS1 and the cutin biosynthesis gene TaCYP86A2. Importantly, chromatin at TaKCS1 and TaCYP86A2 promoters is marked by high nucleosome occupancy and low histone acetylation in TaTOP6A-, TaTOP6B-, TaRHL1-, or TaBIN4-silenced wheat leaves. These results collectively support that wheat topoisomerase VI positively regulates the biosynthesis of cuticular wax and cutin probably via maintaining a permissive chromatin state at TaKCS1 and TaCYP86A2 genes.

A new leaf inhabiting ascomycete from the Jurassic (ca 170 Mya) of Yorkshire, UK, and insights into the appearance and diversification of filamentous Ascomycota

Leaf-associated fungi, the fungi that depend on leaves to sporulate, have a rich Cenozoic record, however their earlier diversity is poorly characterized. Here we describe Harristroma eboracense gen. et sp. nov., a Middle Jurassic leaf-associated fungus colonizing the leaf cuticle of Nilssonia tenuicaulis (cycadophyte). To place our newly described species into a picture of the diversification of Mesozoic fungi, we reassess fossils with leaf-associated stromata in the context of fungal molecular phylogeny. Being melanized, with radiate stromata, and on leaves, H. eboracense and other fossils from the Jurassic and earlier periods are probably related to filamentous Ascomycota in the superclass Leotiomyceta. Characters needed for further resolution of leaf-associated fungal biology and classification, such as the presence of an ostiole for spore discharge and appressoria for entry into leaf tissue first appear in the Mesozoic fossil record. Among Early Cretaceous fossils, Spataporthe taylorii represents the oldest unambiguous evidence of perithecial Sordariomycetes while Protographum luttrellii and Bleximothyrium ostiolatum are the oldest Dothideomycetes thyriothecia. Environmental observations show that broad leaved gymnosperms (especially cycadophytes) growing in warm temperate wet forests might have been the first environment for the radiation of Leotiomyceta.

Pollen and Leaf Micromorphological Characteristics of Spiny Almonds (Prunus subgenus Amygdalus) in Iran.

This study investigates the micromorphological characteristics of pollen grains and leaf epidermal cells from 20 accessions across four species of spiny almonds using scanning electron microscopy. Thirteen quantitative traits of pollen grains, including exine sculpturing, were analyzed alongside qualitative features such as shape, exine sculpture type, and aperture type. Additionally, four quantitative and five qualitative features of the leaf epidermis were examined, focusing on cuticular ornamentation patterns, types of epicuticular wax, and stomatal measurements. The pollen grains were found to be isopolar monads, radially symmetric, medium-sized, varying from prolate spheroidal to prolate, and exhibiting 3-colporate to 3-colpate structures. The exine sculpturing was generally striate with short and long ridges, with or without perforations, and could be classified into three types. Notably, in the Isfahan population of Prunus lycioides and the North Khorasan population of Prunus spinosissima, the exine sculpture types were distinctly different, being rugulate and reticulate, respectively. Multivariate statistical analysis identified equatorial diameter, colpus length and width, and ridge width as key diagnostic markers for species identification within spiny almonds. Principal component analysis and hierarchical clustering further highlighted the significance of stomatal length, cuticular ornamentation patterns, and epicuticular wax types in differentiating among taxa. We conclude that groupings recognized in recent classifications of the subgenus Amygdalus (spiny almonds) remain challenging to delineate solely based on palynological data, as diverse pollen types are present across different clades and subclades. Furthermore, micromorphological leaf traits proved valuable in distinguishing certain spiny almond taxa, and the traits of epidermal cells may reflect the ecological adaptations of spiny almond species.

Harnessing the spatial and transcriptional regulation of monoterpenoid indole alkaloid metabolism in Alstonia scholaris leads to the identification of broad geissoschizine cyclase activities

Monoterpene indole alkaloids (MIAs) are valuable metabolites produced in numerous medicinal plants from the Apocynaceae family such as Alstonia scholaris, which synthesizes strictamine, a MIA displaying neuropharmacological properties of a potential importance. To get insights into the MIA metabolism in A. scholaris, we studied here both the spatial and transcriptional regulations of MIA genes by performing a robust transcriptomics analysis of the main plant organs, leaf epidermis but also by sequencing RNA from leaves transiently overexpressing the master transcriptional regulator MYC2. These transcriptomic studies notably demonstrated that the first steps of the MIA pathway are successively distributed in the internal phloem associated parenchyma and epidermis, and that MYC2 exert a remarkable transcriptional effect by modulating the expression of around 1000 genes. By combining these distinct datasets, we initiated the search for MIA-related genes encoding CYP71, based on the similarity of expression compared to already known MIA genes. Transient expression of these candidates in Nicotiana benthamiana leaves and yeast notably led to the identification of a related isoform of rhazimal synthase (RHS) capable of converting the MIA precursor geissoschizine into akuammicine, strictamine and 16-epi-pleiocarpamine. Investigating its catalytic mechanism revealed that strictamine results from rhazimal deformylation and that a similar mechanism may also explain 16-epi-pleiocarpamine synthesis. This prompted us to rename these enzymes geissoschizine cyclase due to their capacity of cyclizing geissoschizine into three different MIA scaffolds and to form both C-C and C-N bonds. This identification thus illustrates the potential of integrating spatial and transcriptional regulation analysis for MIA gene identification.

Divergent leaf traits of medicinally important Cocculus hirsutus (L.) Diels- Morphoanatomical and Molecular authentication

Cocculus hirsutus (L.) Diels (Menispermaceae) is a perennial liana found mainly in tropical and subtropical regions of the Western Ghats, India. This study investigates the variation in leaf morphology within this species. Five samples were selected based on differences in leaf structure, and morphological analysis of foliar traits (Petiole length, Leaf length and Leaf width) revealed significant variation (p < 0.0001) through one-way ANOVA (F-values for PL = 1247.46, LL = 1303.51, and LW = 1413.46). Principal component analysis (PCA) was used to further explore this diversity. Morphoanatomical features, including leaf epidermis, were examined for accurate species identification. DNA barcoding using matK, rbcL, and combined sequences showed superior results with rbcL and the combined sequence. Maximum likelihood (ML) and Bayesian Inference (BI) were applied to assess species relationships, and the analysis suggested all samples belong to the same species. Nevertheless, discrepancies in the bootstrap and posterior probability values revealed by the rbcL and combined sequences may be attributed to microbial influence or mimicry from the host plant.

Image-Based Quantitative Analysis of Epidermal Morphology in Wild Potato Leaves.

The epidermal leaf patterns of plants exhibit remarkable diversity in cell shapes, sizes, and arrangements, driven by environmental interactions that lead to significant adaptive changes even among closely related species. The Solanaceae family, known for its high diversity of adaptive epidermal structures, has traditionally been studied using qualitative phenotypic descriptions. To advance this, we developed a workflow combining multi-scale computer vision, image processing, and data analysis to extract digital descriptors for leaf epidermal cell morphology. Applied to nine wild potato species, this workflow quantified key morphological parameters, identifying descriptors for trichomes, stomata, and pavement cells, and revealing interdependencies among these traits. Principal component analysis (PCA) highlighted two main axes, accounting for 45% and 21% of variance, corresponding to features such as guard cell shape, trichome length, stomatal density, and trichome density. These axes aligned well with the historical and geographical origins of the species, separating southern from Central American species, and forming distinct clusters for monophyletic groups. This workflow thus establishes a quantitative foundation for investigating leaf epidermal cell morphology within phylogenetic and geographic contexts.

Reduction in the anatomical structure of infected Chrysanthemum morifolium by Puccinia horiana

The commercial production of Chrysanthemum morifolium var. Mustika Kaniya in Malino highland, Indonesia, was limited by white rust infection of Puccinia horiana. This study aimed to compare the leaf and stem sections between healthy and naturally infected plants of Chrysanthemum morifolium by Puccinia horiana. The Johansen method was used to make the sections. The data were analysed using Independent Sample t-Test at α = 5%. The results showed that the pustules were protruded on the abaxial of leaf epidermis and comprised of two cells, oblong, and slightly shrivelled at the middle. The infected chrysanthemum showed the reduction in the leaf tissues (lower epidermis, palisade and spongy mesophyll, vascular bundle, and clear parenchyma) compared to the healthy plant and also reduction in the stem tissues (epidermis, cortex, bundle sheath, and pith). The infection of P. horiana in this study caused the deformation of structural change in both leaf and stem of C. morifolium.

Crocosmia x crocosmiiflora: leaf cuticle and bioclimatic variability

A chemical, morphological, structural, optical, and histological analysis of the waxes of the Crocosmia x crocosmiiflora leaf surfaces was here conducted. The wettability of the adaxial and abaxial leaf surfaces was also examined in detail. The results obtained were correlated with the bioclimatic (thermopluviometric) characterization of this species, based on the wild occurrence of its parental species (C. aurea and C. pottsii). To get a better insight into the potential correlation existent between chemical/morphological/structural characteristics and thermopluviometric data, the data for Crocosmia x crocosmiiflora were subsequently contrasted with the corresponding body of information we reported earlier for seven species with different biogeographic distributions (Ceratonia siliqua L., Cercis siliquastrum L., Arundo donax L., Agapanthus africanus (L.) Hoffmann, Corymbia citriodora (Hook), Eucalyptus gunnii Hook. (Hook), and Eucalyptus globulus Labill). The results of this comparison highlight major correlations between the bioclimatic variability of the species and the chemical composition of waxes, but low or no apparent correlations with the other parameters examined. This conclusion strongly suggests the relevance of the chemical composition of leaf cuticle waxes in describing the response of vascular plants to the environmental matrix.

Integration of Transcriptome and Metabolome Reveals Wax Serves a Key Role in Preventing Leaf Water Loss in Goji (Lycium barbarum)

Drought stress is one of the main abiotic stresses that limit plant growth and affect fruit quality and yield. Plants primarily lose water through leaf transpiration, and wax effectively reduces the rate of water loss from the leaves. However, the relationship between water loss and the wax formation mechanism in goji (Lycium barbarum) leaves remains unclear. ‘Ningqi I’ goji and ‘Huangguo’ goji are two common varieties. In this study, ‘Ningqi I’ goji and ‘Huangguo’ goji were used as samples of leaf material to detect the differences in the water loss rate, chlorophyll leaching rate, wax phenotype, wax content, and components of the two materials. The differences in wax-synthesis-related pathways were analyzed using the transcriptome and metabolome methods, and the correlation among the wax components, wax synthesis genes, and transcription factors was analyzed. The results show that the leaf permeability of ‘Ningqi I’ goji was significantly lower than that of ‘Huangguo’ goji. The total wax content of the ‘Ningqi I’ goji leaves was 2.32 times that of the ‘Huangguo’ goji leaves, and the epidermal wax membrane was dense. The main components of the wax of ‘Ningqi I’ goji were alkanes, alcohols, esters, and fatty acids, the amounts of which were 191.65%, 153.01%, 6.09%, and 9.56% higher than those of ‘Huangguo’ goji, respectively. In the transcriptome analysis, twenty-two differentially expressed genes (DEGs) and six transcription factors (TFs) were screened for wax synthesis; during the metabolomics analysis, 11 differential metabolites were screened, which were dominated by lipids, some of which, like D-Glucaro-1, 4-Lactone, phosphatidic acid (PA), and phosphatidylcholine (PE), serve as prerequisites for wax synthesis, and were significantly positively correlated with wax components such as alkanes by the correlation analysis. A combined omics analysis showed that DEGs such as LbaWSD1, LbaKCS1, and LbaFAR2, and transcription factors such as LbaMYB306, LbaMYB60, and LbaMYBS3 were strongly correlated with wax components such as alkanes and alcohols. The high expression of DEGs and transcription factors is an important reason for the high wax content in the leaf epidermis of ‘Ningqi I’ goji plants. Therefore, by regulating the expression of wax-synthesis-related genes, the accumulation of leaf epidermal wax can be promoted, and the epidermal permeability of goji leaves can be weakened, thereby reducing the water loss rate of goji leaves. The research results can lay a foundation for cultivating drought-tolerant goji varieties.

Integrative multi-omic analysis identifies genes associated with cuticular wax biogenesis in adult maize leaves.

Studying the genetic basis of leaf wax composition and its correlation with leaf cuticular conductance (gc) is crucial for improving crop productivity. The leaf cuticle, which comprises a cutin matrix and various waxes, functions as an extracellular hydrophobic layer, protecting against water loss upon stomatal closure. To address the limited understanding of genes associated with the natural variation of adult leaf cuticular waxes and their connection to gc, we conducted statistical genetic analyses using leaf transcriptomic, metabolomic, and physiological data sets collected from a maize (Zea mays L.) panel of ∼300 inbred lines. Through a random forest analysis with 60 cuticular wax traits, it was shown that high molecular weight wax esters play an important role in predicting gc. Integrating results from genome-wide and transcriptome-wide studies (GWAS and TWAS) via a Fisher's combined test revealed 231 candidate genes detected by all three association tests. Among these, 11 genes exhibit known or predicted roles in cuticle-related processes. Throughout the genome, multiple hotspots consisting of GWAS signals for several traits from one or more wax classes were discovered, identifying four additional plausible candidate genes and providing insights into the genetic basis of correlated wax traits. Establishing a partially shared genetic architecture, we identified 35 genes for both gc and at least one wax trait, with four considered plausible candidates. Our study enhances the understanding of how adult leaf cuticle wax composition relates to gc and implicates both known and novel candidate genes as potential targets for optimizing productivity in maize.

Anatomical Responses of Two Species under Controlled Water Restriction.

Quillay (Quillaja saponaria Molina) and peumo (Cryptocarya alba [Molina] Looser) are two tree species endemic to Chile that grow in Mediterranean climate zones, characterized by a summer season with high temperatures, high solar radiation, and low soil water availability. A study was conducted with 2-year-old Q. saponaria and C. alba plants and two substrate water conditions: well-watered and controlled water restriction. At the end of the study, anatomical leaf modifications were analyzed. The tissues were anatomically described in transverse sections of juvenile and adult leaves, measuring leaf thickness, cuticle thickness, and cell density of the mesophyll parenchymal tissues. In the young leaves of Q. saponaria plants undergoing water restriction treatment, an increase in cuticle and leaf thickness and a decrease in the density of the palisade and spongy parenchyma were observed. In contrast, a significant reduction in leaf thickness was observed in adult leaves of both species with water restriction treatment. The anatomical changes in the leaves of Q. saponaria and C. alba suggest an adaptation to adverse environmental conditions, such as water restriction.

Influence of nanopesticide surface chemistry on adsorption to plant cuticle and wax layer: The role of zeta potential and wetting

Nanopesticidal adsorption on plant surfaces is a critical determinant of their application efficacy, persistence, and ecological impact. In this study, we systematically investigate the impact of surface chemistry on the attachment of nanopesticides for seven different nanocarriers: ethyl lauroyl arginate (ELA, cationic), cocamidopropyl betaine (CAPB, zwitterionic), tween 80 (TW80, nonionic), β-cyclodextrin (βCD), sodium dodecyl sulfate (SDS, anionic), whey protein isolate (WPI), and poloxamer 407 (PXL, nonionic). Azadirachtin from neem seed extract was employed as a model pesticide active ingredient. The nanopesticides were characterized using dynamic light scattering, UV–visible spectroscopy, static contact angle (SCA, θ), and zeta (ζ) potential measurements. Pepper leaves (ζ = −11.6 mV) and candelilla wax (ζ = −2.6 mV) films were utilized to analyze the effect of nanocarrier chemical composition on nanopesticide adsorption. Fluorescence microscopy was utilized to quantify the adsorption of nanopesticides (with fluorophore tagging) on the substrates. It was found that the choice of nanocarrier significantly influenced the adsorption behavior. Nanopesticides with ELA corona, which was cationic with a zeta potential of ∼+19 mV and θ of ∼ 61°, exhibited the highest affinity towards the leaf cuticle and wax substrates, attributed to favorable electrostatic interactions forces. Conversely, nanopesticides with SDS (ζ = −48 mV; θ = 45°), WPI (ζ = −24 mV; θ = 54°), and PXL (ζ = −31 mV; θ = 64°) corona demonstrated the least adsorption. These findings indicate a weak correlation between the wetting behavior of nanopesticide suspensions and nanopesticide adsorption on plant and wax surfaces, as well as a strong correlation between nanopesticide zeta potential and nanopesticide adsorption. These findings heuristically recommend that aqueous cationic and zwitterionic nanocarriers for pesticides provide superior adsorption characteristics on pepper leaves and candelilla wax surfaces. Aqueous macromolecular carriers such as PXL and WPI have performed less effectively in adherence compared to shorter chain amphiphiles with similar zeta potential and wetting characteristics, indicating that the steric and osmotic chain effects of hydrophilic macromolecules hinder the adsorption relative to shorter chains.

Microanatomy sectioning and phytochemicals overview in selected Oleaceae species

This study provides in-depth observations into the microanatomical structure of leaves and stem of eight selected Oleaceae species revealing comprehensive tissue organization using microtome sectioning and peeling leaf epidermis techniques. The phytochemicals profile overview of selected olive species extracted from leaf and stem of Oleaceae species contributes to identifying bioactive compounds with potential therapeutic and medicinal applications. An overview of histochemistry of bioactive metabolites revealed in Oleacee species shows the presence of phenolic compounds (oleuropein and hydroxytyrosol), localized in the leaves and stems, contributing to their antioxidant properties. The present study represent foliar anatomical traits; epidermal cells (ECs) polygonal shape and straight anticlinal walls, paracytic stomata and simple unicellular trichomes. The maximum ECs length (30 μm) was noted in Olea europaea and minimum (20 μm) in Jasminum fluminense was measured. Oleaceae species microtome stem sectioning examined revealed cortex type (parenchyma and collenchyma), vascular bundles (VBs) arrangements (radial, scattered and bundled), xylem vessels (scalariform, annular, spiral and reticulate), phloem fiber arrangements (banded and scattered), and uniseriate, biseriat and multiseriate medullary rays. Stem transverse section with maximum length (1300 μm) was observed in Olea europaea and the lowest (1100 μm) in Jasminum grandiflorum L. subsp. floribundum. This taxonomic histological method links the relationship between anatomy and chemistry, lead to identification of bioactive chemical compounds diversity among Oleaceae species. This anatomical methods used to enhance and consider the plant micromorphological structure-function relationships adapted to diverse environmental conditions.

Triacontanol Reverses Abscisic Acid Effects on Stomatal Regulation in Solanum lycopersicum L. under Drought Stress Conditions

When applied under abiotic stress conditions, triacontanol (TRIA) is effective in regulating the physicochemical processes in plants through mechanisms of defence such as abscisic acid (ABA) signalling. However, TRIA’s role in relation to ABA and stomatal opening is unclear. Therefore, the objective of this study was to evaluate the effects of TRIA and ABA and their combinations on different variables related to stomatal regulation in Solanum lycopersicum, which is subjected to drought stress, and on the leaf epidermis. The negative effects of stress and responses triggered by ABA were reversed in plants treated with TRIA. TRIA increased stomatal conductance and photosynthetic activity in the early hours, and it was determined that TRIA produced larger stomata than did the other treatments. Moreover, the chloroplasts of plants treated with TRIA were significantly smaller and more numerous than those of the control, which could improve CO2 diffusion efficiency and may be related to the regulation of stomatal opening and photosynthesis. Finally, the abaxial epidermis tests reaffirmed the inhibitory effects of TRIA on ABA on stomatal opening. These results confirm the important role of TRIA in regulating various processes in plants and processes triggered by ABA, such as those related to stomatal regulation.

Polar-localized OsLTPG22 regulates rice leaf cuticle deposition and drought response

The cuticle serves as a crucial protective barrier for plant survival, and recent studies have highlighted the essential roles of nonspecific lipid transfer proteins (nsLTPs) in cuticle formation. However, the specific function of nsLTPs in the rice leaf cuticle remains unclear. In this study, we functionally characterized OsLTPG22, a G-type nsLTP with a signal peptide (SP) domain and a glycosylphosphatidylinositol (GPI) anchor region. Mutation in OsLTPG22 led to a reduction in cuticular wax abundance, increased leaf epidermal permeability, and higher drought sensitivity in seedlings. OsLTPG22 was widely expressed in various tissues and exhibited distinct polar localization to the aerial surface of epidermal cells in expanding leaves. OsLTPG22 binds lipids and localizes to the plasma membrane. Protein truncation experiments demonstrated that OsLTPG22’s polar localization was regulated by the SP domain, while both the SP domain and GPI anchor region regulated OsLTPG22’s plasma membrane localization. This work provides genetic and cytological evidence for OsLTPG22’s role in leaf cuticle formation and drought response, enhancing our understanding of nsLTP function and offering insights for breeding drought-resistant crops.

Drought-dependent regulation of cell coupling in Arabidopsis leaf epidermis requires plasmodesmal protein NHL12.

The cytoplasm of most plant cells is connected by membrane-lined cell wall channels, the plasmodesmata (PD). Dynamic regulation of sugar, hormone, and protein diffusion through PD is essential for plant development and stress responses. Understanding this regulation requires knowledge of factors and mechanisms that control PD permeability through the modulation of callose levels in the cell wall around PD openings. We investigated PD regulation in leaf epidermal cells in relation to drought stress in Arabidopsis. PD-mediated cell wall permeability was decreased by drought stress and the hormone abscisic acid (ABA), and we tested how this related to several PD-associated genes with drought-responsive expression. Mutants of NON-RACE SPECIFIC DISEASE RESISTANCE/HIN1 HAIRPIN-INDUCED-LIKE 12 (NHL12) showed relatively low PD permeability that was unaffected by drought or ABA treatment. Overexpression of NHL12 in Nicotiana benthamiana epidermal cells increased PD permeability. Moreover, we showed that NHL12 can potentially interact with the callose synthase regulator NHL3 and we explored the effect of NHL12 abundance and/or lower interface permeability on ABA signaling genes. Our results indicate that NHL12 is a drought-responsive negative regulator of PD callose levels and, thereby, interface permeability. Results are discussed in relation to PD function during drought stress and the regulation of intercellular transport.

Pharmacognostic, physicochemical and phytochemical profiles of Euclea divinorum (Ebenaceae)

Background: Euclea divinorum, belonging to the family Ebeneceae, has extensive traditional medicinal use in Africa. However, it lacks sufficient published data on its pharmacognostic, physicochemical, and phytochemical properties. Aims and Objectives: Thus, this study aimed at comprehensively evaluating the pharmacognostic, physicochemical, and phytochemical properties of E. divinorum using established techniques. Materials and Methods: The evaluation included assessing organoleptic properties, macroscopy, and microscopy of leaves, stems, and roots. Various physicochemical parameters, such as loss on drying and extractive values via hot and cold maceration, were determined. Phytochemical screening was also conducted on root aqueous extracts. Results and Conclusion: Results revealed specific characteristics of E. divinorum leaves, including light green coloration, distinct odor, and bitterness. Macroscopic examination highlighted opposite phyllotaxy, simple leaf types with lamina length range of 71.09 - 93.89 mm and a width range of 6.05 - 17.59 mm, obtuse leaf apexes, cuneate leaf bases, entire leaf margins, and smooth leaf surfaces. Venation displayed a reticulate pattern, with the midrib prominently visible on the lower surface. Microscopic analysis of the lower leaf epidermis showed an average of stomatal density of 3.75±0.67, epidermal density of 35.75±2.16 and stomatal index of 10.47±1.11. Microscopic examination of the leaf lamina across the midrib revealed cortical parenchymal cells containing calcium oxalate crystals, lignified xylem, and non-lignified phloem. Stem cross-sections displayed single-layered cells comprising the epidermis, secondary phloem, secondary xylem, and pith. Similar structures were observed in root cross-sections. The plant's moisture content was found to be 44.8±1.962%, with water and alcohol-soluble extractive values of 7.27±0.17 and 1.13±0.05 g/100g, respectively, through cold maceration, and 14.77±0.28 and 11.43±0.39 g/100g, respectively through hot maceration. The total ash content was measured at 3.03± 0.103%. Phytochemical screening detected various compounds, with anthraquinone glycosides, coumarine glycosides, saponin glycosides, flavonoids, proteins, and tannins being abundant. Alkaloids, cardiac glycosides, and steroids were absent. This research contributes to standardizing E. divinorum, aiding in its identification, preventing adulteration, and ensuring therapeutic efficacy.

Genome-wide identification of metal tolerance protein genes in Quercus dentata and their roles in response to various heavy metal stresses

Metal tolerance protein (MTP) is a cation transporter that plays an important role in tolerance to heavy metal stress. However, thus far, there has been no genome-wide investigation of the MTP gene family in Quercus plants. Quercus dentata is one of the main constructive species of forest in northern China. It has strong tolerance to a variety of heavy metal stresses. In this study, 25 MTPs were identified from the Q. dentata genome and classified into three subfamilies and seven groups according to their sequence characteristics and phylogenetic relationships. Both tandem and segmental duplication events contributed to the expansion of the QdMTP gene family. Interestingly, all 10 tandem duplication events contributed to the expansion of the Mn-CDF subfamily. The expression of Mn-CDF subfamily members in different organs and tissues of Q. dentata was different, and they responded differently to manganese, iron, zinc and cadmium stress treatments. QdMTP10.7, a member of the Mn-CDF subfamily, enhanced yeast growth under manganese, zinc and iron stresses. The subcellular localization in tobacco leaf epidermis cells showed that QdMTP10.7 was located in vacuoles. These data generated from this study provide an important foundation to elucidate the biological roles of QdMTP genes related to heavy metal tolerance in Q. dentata.

BHLH transcription factors cooperate with chromatin remodelers to regulate cell fate decisions during Arabidopsis stomatal development.

The development of multicellular organisms requires coordinated changes in gene expression that are often mediated by the interaction between transcription factors (TFs) and their corresponding cis-regulatory elements (CREs). During development and differentiation, the accessibility of CREs is dynamically modulated by the epigenome. How the epigenome, CREs, and TFs together exert control over cell fate commitment remains to be fully understood. In the Arabidopsis leaf epidermis, meristemoids undergo a series of stereotyped cell divisions, then switch fate to commit to stomatal differentiation. Newly created or reanalyzed scRNA-seq and ChIP-seq data confirm that stomatal development involves distinctive phases of transcriptional regulation and that differentially regulated genes are bound by the stomatal basic helix-loop-helix (bHLH) TFs. Targets of the bHLHs often reside in repressive chromatin before activation. MNase-seq evidence further suggests that the repressive state can be overcome and remodeled upon activation by specific stomatal bHLHs. We propose that chromatin remodeling is mediated through the recruitment of a set of physical interactors that we identified through proximity labeling-the ATPase-dependent chromatin remodeling SWI/SNF complex and the histone acetyltransferase HAC1. The bHLHs and chromatin remodelers localize to overlapping genomic regions in a hierarchical order. Furthermore, plants with stage-specific knockdown of the SWI/SNF components or HAC1 fail to activate specific bHLH targets and display stomatal development defects. Together, these data converge on a model for how stomatal TFs and epigenetic machinery cooperatively regulate transcription and chromatin remodeling during progressive fate specification.