Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 794
Filtrar
1.
Int J Mol Sci ; 25(5)2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38473801

RESUMO

Epidermal cells are the main avenue for signal and material exchange between plants and the environment. Leaf epidermal cells primarily include pavement cells, guard cells, and trichome cells. The development and distribution of different epidermal cells are tightly regulated by a complex transcriptional regulatory network mediated by phytohormones, including jasmonic acid, and transcription factors. How the fate of leaf epidermal cells is determined, however, is still largely unknown due to the diversity of cell types and the complexity of their regulation. Here, we characterized the transcriptional profiles of epidermal cells in 3-day-old true leaves of Arabidopsis thaliana using single-cell RNA sequencing. We identified two genes encoding BASIC LEUCINE-ZIPPER (bZIP) transcription factors, namely bZIP25 and bZIP53, which are highly expressed in pavement cells and early-stage meristemoid cells. Densities of pavement cells and trichome cells were found to increase and decrease, respectively, in bzip25 and bzip53 mutants, compared with wild-type plants. This trend was more pronounced in the presence of jasmonic acid, suggesting that these transcription factors regulate the development of trichome cells and pavement cells in response to jasmonic acid.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Ciclopentanos , Oxilipinas , Fatores de Transcrição de Zíper de Leucina Básica , Células Epidérmicas , Fatores de Transcrição , Folhas de Planta , Tricomas , Análise de Sequência de RNA , Regulação da Expressão Gênica de Plantas
2.
Nat Commun ; 15(1): 2303, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38491132

RESUMO

About one third of vascular plants develop glandular trichomes, which produce defensive compounds that repel herbivores and act as a natural biofactory for important pharmaceuticals such as artemisinin and cannabinoids. However, only a few regulators of glandular structures have been characterized so far. Here we have identified two closely-related MYB-like genes that redundantly inhibit the formation of glandular cells in tomatoes, and they are named as GLAND CELL REPRESSOR (GCR) 1 and 2. The GCR genes highly express in the apical cells of tomato trichomes, with expression gradually diminishing as the cells transition into glands. The spatiotemporal expression of GCR genes is coordinated by a two-step inhibition process mediated by SlTOE1B and GCRs. Furthermore, we demonstrate that the GCR genes act by suppressing Leafless (LFS), a gene that promotes gland formation. Intriguingly, homologous GCR genes from tobacco and petunia also inhibit gland formation, suggesting that the GCR-mediated repression mechanism likely represents a conserved regulatory pathway for glands across different plant species.


Assuntos
Solanum lycopersicum , Fatores de Transcrição , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Tricomas , Solanum lycopersicum/genética , Plantas Geneticamente Modificadas/metabolismo , Regulação da Expressão Gênica de Plantas
3.
Commun Biol ; 7(1): 352, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519601

RESUMO

Many biological surfaces have hairs, known as trichomes in plants. Here, the wettability and macro- and micro-scale features of olive leaves are analyzed. The upper leaf side has few trichomes, while the lower side has a high trichome density. By combining different techniques including electron and atomic force microscopy, trichome surfaces are found to be chemically (hydrophilic-hydrophobic) heterogeneous at the nano-scale. Both olive leaf surfaces are wettable by water, having a high water contact angle hysteresis and great drop adhesion. The ultra-structural pattern observed for epidermal pavement cells differs from the reticulate cuticle structure of trichomes which shows that leaf surface areas may be substantially different despite being located nearby. Our study provides evidence for the nano-scale chemical heterogeneity of a trichome which may influence the functional properties of biological surfaces, such as water and solute permeability or water capture as discussed here for plants.


Assuntos
Olea , Tricomas , Folhas de Planta/química , Água
4.
5.
Mol Genet Genomics ; 299(1): 19, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38416229

RESUMO

KEY MESSAGE: GaKAN2, a member of the KANADI family, was found to be widely expressed in the cotton tissues and regulates trichome development through complex pathways. Cotton trichomes are believed to be the defense barrier against insect pests. Cotton fiber and trichomes are single-cell epidermal extensions with shared regulatory mechanisms. Despite several studies underlying mechanism of trichome development remains elusive. The KANADI is one of the key transcription factors (TFs) family, regulating Arabidopsis trichomes growth. However, the function of KANADI genes in cotton remains unknown. In the current study genome-wide scanning, transcriptomic analysis, gene silencing, subcellular localization, and yeast two-hybrid techniques were employed to decipher the function of KANADI TFs family genes in cotton crop. A total of 7 GaKAN genes were found in the Gossypium arboreum. Transcriptomic data revealed that these genes were significantly expressed in stem and root. Moreover, GaKAN2 was widely expressed in other tissues also. Subsequently, we selected GaKAN2 to validate the function of KANADI genes. Silencing of GaKAN2 resulted in a 24.99% decrease in single-cell trichomes and an 11.33% reduction in internodal distance, indicating its potential role in regulating trichomes and plant growth. RNA-Seq analysis elucidated that GaSuS and GaERS were the downstream genes of GaKAN2. The transcriptional activation and similarity in silencing phenotype between GaKAN2 and GaERS suggested that GaKAN2 regulates trichomes development through GaERS. Moreover, KEGG analysis revealed that a significant number of genes were enriched in the biosynthesis of secondary metabolites and plant hormone signal transduction pathways, thereby suggesting that GaKAN2 regulates the stem trichomes and plant growth. The GFP subcellular localization and yeast transcriptional activation analysis elucidated that GaKAN2 was located in the nucleus and capable of regulating the transcription of downstream genes. This study elucidated the function and characteristics of the KANADI gene family in cotton, providing a fundamental basis for further research on GaKAN2 gene in cotton plant trichomes and plant developmental processes.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Fatores de Transcrição/genética , Gossypium/genética , Tricomas/genética , Saccharomyces cerevisiae , Regulação da Expressão Gênica
6.
Science ; 383(6683): 659-666, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38330135

RESUMO

Secretory structures in terrestrial plants serve as reservoirs for a variety of secondary metabolites. Among these, the secretory cavity of the Rutaceae family is notable for containing essential oils with a wide range of applications. However, the molecular basis underlying secretory cavity development is unknown. Here, we reveal a molecular framework for Citrus oil gland formation. Using genetic mapping and genome editing, we demonstrated that this process requires LATE MERISTEM IDENTITY1 (LMI1), a key regulator of leaf serration. A conserved GCC box element of the LMI1 promoter recruits DORNROSCHEN-like (DRNL) for transcriptional activation. This DRNL-LMI1 cascade triggers MYC5 activation, facilitating the development of oil glands and the biosynthesis of essential oils. Our findings spotlight cis-regulatory divergence within leaf shape genes, propelling novel functional tissue formation.


Assuntos
Citrus , Óleos Voláteis , Proteínas de Plantas , Fatores de Transcrição , Tricomas , Citrus/genética , Citrus/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Óleos Voláteis/metabolismo , Tricomas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
7.
PeerJ ; 12: e16722, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38406271

RESUMO

Quantitative trait loci (QTL) mapping is used for the precise localization of genomic regions regulating various traits in plants. Two major QTLs regulating Soil Plant Analysis Development (SPAD) value (qSPAD-7-1) and trichome density (qTric-7-2) in mungbean were identified using recombinant inbred line (RIL) populations (PMR-1×Pusa Baisakhi) on chromosome 7. Functional analysis of QTL region identified 35 candidate genes for SPAD value (16 No) and trichome (19 No) traits. The candidate genes regulating trichome density on the dorsal leaf surface of the mungbean include VRADI07G24840, VRADI07G17780, and VRADI07G15650, which encodes for ZFP6, TFs bHLH DNA-binding superfamily protein, and MYB102, respectively. Also, candidate genes having vital roles in chlorophyll biosynthesis are VRADIO7G29860, VRADIO7G29450, and VRADIO7G28520, which encodes for s-adenosyl-L-methionine, FTSHI1 protein, and CRS2-associated factor, respectively. The findings unfolded the opportunity for the development of customized genotypes having high SPAD value and high trichome density having a possible role in yield and mungbean yellow vein mosaic India virus (MYMIV) resistance in mungbean.


Assuntos
Locos de Características Quantitativas , Vigna , Locos de Características Quantitativas/genética , Vigna/genética , Mapeamento Cromossômico , Genótipo , Solo , Tricomas/genética , Folhas de Planta/genética
8.
Nat Plants ; 10(3): 381-389, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38374437

RESUMO

Successful biochemical reactions in organisms necessitate compartmentalization of the requisite components. Glandular trichomes (GTs) act as compartments for the synthesis and storage of specialized compounds. These compounds not only are crucial for the survival of plants under biotic and abiotic stresses but also have medical and commercial value for humans. However, the mechanisms underlying compartmentalization remain unclear. Here we identified a novel structure that is indispensable for the establishment of compartments in cucumber GTs. Silica, a specialized compound, is deposited on the GTs and is visible on the surface of the fruit as a white powder, known as bloom. This deposition provides resistance against pathogens and prevents water loss from the fruits1. Using the cucumber bloomless mutant2, we discovered that a lignin-based cell wall structure in GTs, named 'neck strip', achieves compartmentalization by acting as an extracellular barrier crucial for the silica polymerization. This structure is present in the GTs of diverse plant species. Our findings will enhance the understanding of the biosynthesis of unique compounds in trichomes and provide a basis for improving the production of compounds beneficial to humans.


Assuntos
Cucumis sativus , Lignina , Humanos , Tricomas , Plantas , Dióxido de Silício
9.
Plant Cell Environ ; 47(4): 1300-1318, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38221803

RESUMO

Plants synthesize abundant terpenes through glandular trichomes (GTs), thereby protecting themselves from environmental stresses and increasing the economic value in some medicinal plants. However, the potential mechanisms for simultaneously regulating terpenes synthesis and GTs development remain unclear. Here, we showed that terpenes in Conyza blinii could be synthesized through capitate GTs. By treating with appropriate intensity of UV-B, the density of capitate GTs and diterpene content can be increased. Through analyzing corresponding transcriptome, we identified a MYB transcription factor CbMYB108 as a positive regulator of both diterpene synthesis and capitate GT density. Transiently overexpressing/silencing CbMYB108 on C. blinii leaves could increase diterpene synthesis and capitate GT density. Further verification showed that CbMYB108 upregulated CbDXS and CbGGPPS expression in diterpene synthesis pathway. Moreover, CbMYB108 could also upregulated the expression of CbTTG1, key WD40 protein confirmed in this study to promote GT development, rather than through interaction between CbMYB108 and CbTTG1 proteins. Thus, results showed that the UV-B-induced CbMYB108 owned dual-function of simultaneously improving diterpene synthesis and GT development. Our research lays a theoretical foundation for cultivating C. blinii with high terpene content, and broadens the understanding of the integrated mechanism on terpene synthesis and GT development in plants.


Assuntos
Conyza , Diterpenos , Conyza/metabolismo , Tricomas/metabolismo , Terpenos/metabolismo , Diterpenos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
Gene ; 904: 148213, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38281672

RESUMO

The leaves of Artemisia annua contain GSTs (Glandular secretory trichomes) that can secrete and store artemisinin, the drug most effective for treating uncomplicated malaria. Therefore, increasing the density of GSTs in A. annua is an efficient way to enhance artemisinin content. However, our understanding of how GSTs develop still needs to be improved. Here, we isolated an A. annua homolog of AtGL3 (GLABRA3), known as AaGL3-like, that positively regulates trichome density in A. annua. AaGL3-like is nuclear-localized and transcriptionally active. It is least expressed in roots and most prominently in aerial components like leaves, stems, and inflorescence. Under JA and GA hormonal treatments, AaGL3-like expression is significantly increased. In transgenic over-expression AaGL3-like lines, trichome developmental genes such as AaHD1 and AaGSW2 showed much increased expression. The AaGL3RNAi line exhibited considerably lower levels of AaHD1 and AaGSW2 transcripts. As a result, the AaGL3-RNAi lines showed reduced levels of artemisinin content and trichome density compared to wild-type and overexpression lines. Additionally, we have found that when co-expressed with AaJAZ8, the induction of trichome developmental genes was reduced as compared to individual OEAaGL3-like lines. Further, AaJAZ8 directly binds to AaGL3-like in the Y2H assay. These findings suggest that AaGL3-like is a jasmonate-induced bHLH transcription factor that drastically increases the final accumulation of artemisinin content by regulating trichome density in A. annua.


Assuntos
Artemisia annua , Artemisininas , Ciclopentanos , Oxilipinas , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Tricomas/genética , Tricomas/metabolismo , Artemisia annua/genética , Artemisia annua/metabolismo , Artemisininas/farmacologia , Proteínas de Plantas/metabolismo
11.
BMC Plant Biol ; 24(1): 62, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38262916

RESUMO

Nectar guide trichomes play crucial ecological roles in bee-pollinated flowers, as they serve as footholds and guides for foraging bees to access the floral rewards. However, the genetic basis of natural variation in nectar guide trichomes among species remains poorly understood. In this study, we performed genetic analysis of nectar guide trichome variation between two closely related monkeyflower (Mimulus) species, the bumblebee-pollinated Mimulus lewisii and self-pollinated M. parishii. We demonstrate that a MIXTA-like R2R3-MYB gene, GUIDELESS, is a major contributor to the nectar guide trichome length variation between the two species. The short-haired M. parishii carries a recessive allele due to non-synonymous substitutions in a highly conserved motif among MIXTA-like MYB proteins. Furthermore, our results suggest that besides GUIDELESS, additional loci encoding repressors of trichome elongation also contribute to the transition from bumblebee-pollination to selfing. Taken together, these results suggest that during a pollination syndrome switch, changes in seemingly complex traits such as nectar guide trichomes could have a relatively simple genetic basis, involving just a few genes of large effects.


Assuntos
Mimulus , Néctar de Plantas , Abelhas , Animais , Tricomas , Polinização , Flores
12.
Microsc Res Tech ; 87(3): 434-445, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37909218

RESUMO

The genus Ajuga is widely distributed in temperate to subtropical regions, and four species are currently recognized in Korea (A. decumbens, A. multiflora, A. nipponensis, and A. spectabilis), but epidermal anatomical differences across these species have never been described. A comparative study of the leaf micromorphological characteristics of Korean Ajuga species was performed using light microscopy (LM) and scanning electron microscopy (SEM) to elucidate their taxonomic usefulness and to assess leaf micromorphological diversity. Considerable diversity in epidermal and stomatal anatomy was observed across Korean Ajuga species. Species had both hypostomatic or amphistomatic leaves, with anomocytic, anisocytic, diactyic, or actinocytic stomatal complexes. Guard cell length across species ranged from 17.66 ± 0.57 µm to 32.50 ± 2.38 µm and correlated with genome size. Abnormal stomata were frequently observed in three species (A. decumbens, A. multiflora, and A. nipponensis) but not in A. spectabilis. Three types of glandular trichomes were found: peltate in all species, short-stalked in all species, and long-stalked glandular trichomes in A. multiflora. Among the investigated leaf micromophological characters, trichome type, epidermal cell shape, and stomatal morphology were all taxonomically informative traits at a species level. RESEARCH HIGHLIGHTS: A comprehensive micromorphological description of the leaf surface is provided for Korean Ajuga species using scanning electron microscopic (SEM) and light microscopic (LM) analyses. The diverse range of stomatal development and the occurrence of polymorphic stomatal types are documented for the first time in Korean Ajuga species. The great diversity in stomatal and trichome morphology in Korean Ajuga species are taxonomically useful traits for species identification.


Assuntos
Ajuga , Estômatos de Plantas , Estômatos de Plantas/ultraestrutura , Epiderme Vegetal/ultraestrutura , Folhas de Planta/anatomia & histologia , Tricomas/ultraestrutura , Microscopia Eletrônica de Varredura , Células Epidérmicas , Epiderme , República da Coreia
13.
Microsc Res Tech ; 87(3): 534-545, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37950576

RESUMO

Aconitum napellus L. is a popular medicinal plant extensively used in homeopathy. This article provides detailed morphology and microscopy, including the anatomical and histochemical features of the herb, to aid authentication and quality control. In cross-section, the root in secondary growth shows the phloem surrounded by pericyclic fibers and a well-developed xylem. The stem is irregular in outline, displaying unicellular trichomes and many free collateral vascular bundles encircling the pith. The leaf is dorsiventral, hypostomatic with anomocytic and anisocytic stomata, and shows non-glandular trichomes. The floral parts are characterized by uniseriate epidermises, homogeneous mesophyll, anomocytic stomata on the abaxial surface, trichomes, and oval pollen grains. The tissue fragments in powdered herbs show these characteristics and have numerous starch grains with thimble-shaped, linear or star-shaped hilum. The detailed macroscopic and microscopic analysis provided in this study can help in the authentication and quality control of A. napellus raw materials. RESEARCH HIGHLIGHTS: Key anatomical, micromorphological, and microchemical features of Aconitum napellus are described. The results of the study can support the taxonomy of the genus Aconitum. Morphological standardization of the species reported here is helpful in the quality control of this herb.


Assuntos
Aconitum , Estômatos de Plantas , Estômatos de Plantas/ultraestrutura , Folhas de Planta/anatomia & histologia , Epiderme Vegetal/ultraestrutura , Tricomas/ultraestrutura , Microscopia Eletrônica de Varredura
14.
Microsc Res Tech ; 87(3): 446-469, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37920931

RESUMO

This is a very first attempt to study various parameters of a medicinal plant, Delphinium suave Huth. The plant is erect, geophytic, herbaceous, with tuberous root, trifid in a palmatipartite, strigose cuneate leaf and white spurred zygomorphic flower. The root was isodiametric phellem with single non-glandular trichomes. The stem revealed single-layered cuticle, multiseriate epidermis, cortex, pith ray and uniserate bowed non-glandular trichomes. The leaf was amphistomatic, showed tapering trichomes, prismatic crystals and ranunculaceous stomata with circumference 144.66-182.67 µm. Pollen grains in Light Microscopy (LM), were prolate, spheroidal trizonocolpate, isopolar, radiosymmetric, scabrate, elliptic and monads. Scanning Electron Microscope (SEM) pollen surface was scabrate, monad, size varied from 18.06 to 16.67 µm, colpus to inaperturate, tricolpate, ornamented, echinus, isopolar, isodiametric and circular. SEM roots showed sclerenchymatic tissues, stellate, glandular, non-glandular trichomes and crystals. The stem showed scalariform, pitted vessels, warty protuberances, unicellular, silicified, non-glandular trichomes. Leaves powder revealed, simple, unicellular, tapered headed, uniseriate, sessile, capitate, unbranched glandular, non-glandular, trichomes with crystals. Capitate, stellate, circular, unicellular, branchy trichomes were observed for the first time through SEM. Powder drug study of root, stem leaves through LM revealed different tissues. Preliminary phytochemical revealed alkaloids, anthocyanins, anthraquinones, coumarins, flavones, mucilages, saponins, steroids, terpenoids, volatile oils and proteins. GC/MS showed 36 compounds in roots, 33 in stem while 40 in leaves. Fluorescence analysis of roots, stem and leaves showed variations in color when treated with chemicals. This study will assist pharmacognostic exploration, authentication from adulterants/allied species for consistent quality, resulting in safe use, preservation and efficacy. RESEARCH HIGHLIGHTS: This was first attempt on pharmacognostic study on D. suave Huth. which could be used as a foundation for identifying and authenticating the specie from other allied species by these morphological, anatomical, GC/MS profiling, phytochemical analysis and fluorescence analysis.


Assuntos
Delphinium , Microscopia Eletrônica de Varredura , Paquistão , Antocianinas/análise , Pós/análise , Folhas de Planta/anatomia & histologia , Tricomas/anatomia & histologia , Compostos Fitoquímicos/análise
15.
Plant J ; 117(4): 1084-1098, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37934816

RESUMO

Plant cell wall polysaccharides, including xylan, mannan, xyloglucan, and pectins, are often acetylated and members of the domain of unknown function 231 (DUF231)/trichome birefringence-like (TBL) family have been shown to be O-acetyltransferases mediating the acetylation of xylan, mannan, and xyloglucan. However, little is known about the O-acetyltransferases responsible for pectin acetylation. In this report, we biochemically characterized a suite of Arabidopsis DUF231/TBL proteins for their roles in pectin acetylation. We generated 24 TBL recombinant proteins in mammalian cells and demonstrated that 10 of them were able to transfer acetyl groups from acetyl-CoA onto the pectins homogalacturonan (HG) or rhamnogalacturonan-I (RG-I), and thus were named pectin O-acetyltransferase 1 to 10 (POAT1 to 10). It was found that POAT2,4,9,10 specifically acetylated HG and POAT5,6 acetylated RG-I, whereas POAT1,3,7,8 could act on both HG and RG-I. The acetylation of HG and RG-I by POATs was further corroborated by hydrolysis with pectin acetylesterases and by nuclear magnetic resonance spectroscopy. In addition, mutations of the conserved GDS and DXXH motifs in POAT3 and POAT8 were shown to lead to a loss of their ability to acetylate HG and RG-I. Furthermore, simultaneous RNA interference downregulation of POAT1,3,6,7,8 resulted in reduced cell expansion, impaired plant growth, and decreased pectin acetylation. Together, our findings indicate that these POATs are pectin O-acetyltransferases involved in acetylation of the pectin polysaccharides HG and RG-I.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Xilanos/metabolismo , Ramnogalacturonanos/análise , Ramnogalacturonanos/metabolismo , Mananas/metabolismo , Acetilação , Birrefringência , Tricomas/metabolismo , Pectinas/metabolismo , Polissacarídeos/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Acetiltransferases/genética , Acetiltransferases/metabolismo , Catálise , Parede Celular/metabolismo
16.
Protoplasma ; 261(2): 245-256, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37698669

RESUMO

Secretory trichomes and colleters are two of the secretory structures whose exudates may cover the body of the plant. Such secretions comprise resins or mucilages which are associated with an array of ecological roles. In Rosaceae, secretory trichomes have been reported for the leaves while colleters associated with leaf teeth. Our study aimed to identify the secretory structures of Rosa lucieae and understand the ecological role played by these glands as interpreted by morphoanatomical and histochemical studies. Samples from developing and fully mature leaves were collected, fixed, and processed according to usual techniques for light and scanning electron microscopy. In R. lucieae, colleters are restricted to the leaf and stipular margins and are associated with the teeth. They present a parenchymatous axis surrounded by a secretory palisade epidermis and usually fall off after the secretory activity is finished. Different from colleters, secretory trichomes are persistent. They present a multicellular secretory head and stalk. They are found at the base of the leaflet, petiolule, rachis, and petiole and occasionally on the stipular and leaf margins. The colleters predominantly secrete mucilages while the secretory trichomes secrete lipids and terpenes, both via cuticle rupture. The secretory activity of colleters is predominant in the leaf primordia, holding leaflets together and protecting meristems and leaves from desiccation, while the secretory trichomes maintain their secretory activity at different stages of leaf development, protecting different regions of the leaf against pathogens and herbivores.


Assuntos
Rosa , Folhas de Planta/química , Microscopia Eletrônica de Varredura , Meristema , Tricomas
17.
Plant Sci ; 339: 111959, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38101619

RESUMO

Glandular trichomes are specialized structures found on the surface of plants to produce specific compounds, including terpenes, alkaloids, and other organic substances. Artemisia annua, commonly known as sweet wormwood, synthesizes and stores the antimalarial drug artemisinin in glandular trichomes. Previous research indicated that increasing the glandular trichome density could enhance artemisinin production, and the cuticle synthesis affected the initiation and development of glandular trichomes in A. annua. In this study, AaABCG12 and AaABCG20 were isolated from A. annua that exhibited similar expression patterns to artemisinin biosynthetic genes. Of the two, AaABCG20 acted as a specific transporter in glandular trichomes. Downregulating the expression of AaABCG20 resulted in a notable reduction in the density of glandular trichome, while overexpressing AaABCG20 resulted in an increase in glandular trichome density. GC-MS analysis demonstrated that AaABCG20 was responsible for the transport of cutin and wax in A. annua. These findings indicated that AaABCG20 influenced the initiation and development of glandular trichomes through transporting cutin and wax in A. annua. This glandular trichome specific half-size ABCG-type transporter is crucial in facilitating the transportation of cutin and wax components, ultimately contributing to the successful initiation and development of glandular trichomes.


Assuntos
Artemisia annua , Artemisininas , Lipídeos de Membrana , Tricomas , Artemisia annua/genética , Artemisia annua/metabolismo , Proteínas de Plantas/metabolismo , Artemisininas/metabolismo
18.
Braz J Biol ; 83: e273614, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37937623

RESUMO

Bauhinia pulchella Benth. (Fabaceae), is native to Brazil and popularly known as pata-de-bode. In folk medicine, it is used to treat diabetes. Pharmacological studies have demonstrated different properties, such as cytotoxic and antioxidant, and different chemical constituents, such as essential oil, triterpenoids, steroids, among others. In order to highlight the morphological differences of the species B. pulchella from the others of the genus, and its pharmacological potential, the present study aimed to carry out the anatomical and histochemical characterization of the stem and leaves of B. pulchella. Usual methods in plant anatomy were used in the preparation of semi-permanent slides containing cross sections of the stem, petiole and leaf blade and paradermal sections of the leaf blade for analysis in light microscopy and polarized light. Histochemical tests were also performed to localize the metabolites in the stem and leaf blade. The stem of B. pulchella has a cylindrical outline, the bark is composed of 7-8 layers of cells and discontinuously distributed sclerenchyma; petiole presents flat convex contour, prominences in the adaxial region, concentric amphicrivral vascular bundle, surrounding a small concentric anfivasal intramedullary bundle, adaxially two accessory bundles and tector trichomes; leaf blade with anisocytic and tetracytic stomata on the adaxial surface and anisocytic, tetracytic and anomocytic on the abaxial surface; and midrib with plain-convex outline, 1-2 layers of collenchyma and covering trichomes. Characteristics that differ from other species of the genus Bauhinia. Alkaloids, phenolic compounds, lipophilic compounds, lignin, triterpenes, steroids and tannins were observed in the species. The results are fundamental for the pharmacobotanical standardization of the studied species.


Assuntos
Bauhinia , Fabaceae , Folhas de Planta/anatomia & histologia , Tricomas , Esteroides
19.
Zhongguo Zhong Yao Za Zhi ; 48(18): 4950-4958, 2023 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-37802836

RESUMO

The quality of moxa is a key factor affecting the efficacy of moxibustion. Traditional moxa grades are evaluated by the leaf-to-moxa ratio, but there is a lack of support from scientific data. Scanning electron microscopy(SEM), Image Pro Plus, Van Soest method, and stimultaneous thermal analysis(TGA/DSC) were used to characterize the scientific implication of the combustion differences between moxa with different leaf-to-moxa ratios(processed by crusher). The results showed that the median lengths from non-secretory trichomes(NSTs) of natural NSTs and moxa with leaf-to-moxa ratios of 3∶1, 5∶1, 10∶1, and 15∶1 were 542.46, 303.24, 291.18, 220.69, and 170.61 µm, respectively. The cellulose content of moxa increased significantly(P<0.05) with the increase in leaf-to-moxa ratio and the combustion parameters(T_i, t_i, D_i, C,-R_p,-R_v, S, D_b, and J_(total)) all showed an increasing trend. The correlation results showed that the burning properties of moxa(T_i,-R_v, t_i, and J_2) were significantly and positively correlated with cellulose content. NSTs with a length of 1-200 µm were significantly and positively correlated with J_2. NSTs with a length of 200-600 µm were significantly and positively correlated with J_1, T_(peak2), T_(peak1), and-R_v, and negatively correlated with J_(total), T_b, and t_b. As the leaf-to-moxa ratio increases, the NSTs in the moxa become shorter and the cellulose content increases, which is more conducive to ignition performance, heat release, and a milder, longer-lasting burn. The "NSTs-cellulose-TGA/DSC" quantitative evaluation method scientifically reveals the scientific connotation of the combustion of moxa with different leaf-to-moxa ratios and provides a scientific basis for the establishment of quality evaluation methods for moxa with different leaf-to-moxa ratios.


Assuntos
Moxibustão , Tricomas , Temperatura Alta , Folhas de Planta
20.
Proc Natl Acad Sci U S A ; 120(42): e2309616120, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37824528

RESUMO

Biological patterns that emerge during the morphogenesis of multicellular organisms can display high precision at large scales, while at cellular scales, cells exhibit large fluctuations stemming from cell-cell differences in molecular copy numbers also called demographic noise. We study the conflicting interplay between high precision and demographic noise in trichome patterns on the epidermis of wild-type Arabidopsis thaliana leaves, as a two-dimensional model system. We carry out a statistical characterization of these patterns and show that their power spectra display fat tails-a signature compatible with noise-driven stochastic Turing patterns-which are absent in power spectra of patterns driven by deterministic instabilities. We then present a theoretical model that includes demographic noise stemming from birth-death processes of genetic regulators which we study analytically and by stochastic simulations. The model captures the observed experimental features of trichome patterns.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Tricomas/metabolismo , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Folhas de Planta/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...