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1.
Plant Sci ; 321: 111256, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35696901

RESUMO

The aerial surfaces of plants are covered by a layer of cuticular wax that is composed of long-chain hydrocarbon compounds for protection against adverse environmental conditions. The current study identified a maize (Zea mays L.) APETALA2/ethylene-responsive element-binding protein (AP2/EREBP)-type transcription factor, ZmEREB46. Ectopic expression of ZmEREB46 in Arabidopsis increased the accumulation of epicuticular wax on the leaves and enhanced the drought tolerance of plants. The amounts of C24/C32 fatty acids, C32/C34 aldehydes, C32/C34 1-alcohols and C31 alkanes in zmereb46 (ZmEREB46 knockout mutant) leaves were reduced. The amount of leaf total epicuticular wax decreased approximately 50% in zmereb46. Compared to wild-type LH244 leaves, the cuticle permeability of zmereb46 leaves was increased, which resulted from decreased epicuticular wax load and a thinner cuticle layer. ZmEREB46 had transcriptional activation activity and directly bound to promoter regions of ZmCER2, ZmCER3.2 and ZmKCS1. The zmereb46 seedlings also exhibited reduced drought tolerance. These results, and the observations in ZmEREB46-overexpressing lines, suggest that ZmEREB46 is involved in cuticular metabolism by influencing the biosynthesis of very-long-chain waxes and participates in the cutin biosynthesis pathway. These results are helpful to further analyze the regulatory network of wax accumulation in maize.


Assuntos
Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Secas , Regulação da Expressão Gênica de Plantas , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo , Ceras/química , Zea mays/genética , Zea mays/metabolismo
2.
J Exp Bot ; 73(9): 2799-2816, 2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35560199

RESUMO

Plants are sessile organisms that have developed hydrophobic cuticles that cover their aerial epidermal cells to protect them from terrestrial stresses. The cuticle layer is mainly composed of cutin, a polyester of hydroxy and epoxy fatty acids, and cuticular wax, a mixture of very-long-chain fatty acids (>20 carbon atoms) and their derivatives, aldehydes, alkanes, ketones, alcohols, and wax esters. During the last 30 years, forward and reverse genetic, transcriptomic, and biochemical approaches have enabled the identification of key enzymes, transporters, and regulators involved in the biosynthesis of cutin and cuticular waxes. In particular, cuticular wax biosynthesis is significantly influenced in an organ-specific manner or by environmental conditions, and is controlled using a variety of regulators. Recent studies on the regulatory mechanisms underlying cuticular wax biosynthesis have enabled us to understand how plants finely control carbon metabolic pathways to balance between optimal growth and development and defense against abiotic and biotic stresses. In this review, we summarize the regulatory mechanisms underlying cuticular wax biosynthesis at the transcriptional, post-transcriptional, post-translational, and epigenetic levels.


Assuntos
Arabidopsis , Arabidopsis/genética , Carbono/metabolismo , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica de Plantas , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo , Plantas/genética , Plantas/metabolismo , Estresse Fisiológico , Ceras/metabolismo
4.
J Exp Bot ; 73(9): 3018-3029, 2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35560209

RESUMO

The alcohol- and alkane-forming pathways in cuticular wax biosynthesis are well characterized in Arabidopsis. However, potential interactions between the two pathways remain unclear. Here, we reveal that mutation of CER4, the key gene in the alcohol-forming pathway, also led to a deficiency in the alkane-forming pathway in distal stems. To trace the connection between the two pathways, we characterized two homologs of fatty alcohol oxidase (FAO), FAO3 and FAO4b, which were highly expressed in distal stems and localized to the endoplasmic reticulum. The amounts of waxes from the alkane-forming pathway were significantly decreased in stems of fao4b and much lower in fao3 fao4b plants, indicative of an overlapping function for the two proteins in wax synthesis. Additionally, overexpression of FAO3 and FAO4b in Arabidopsis resulted in a dramatic reduction of primary alcohols and significant increases of aldehydes and related waxes. Moreover, expressing FAO3 or FAO4b led to significantly decreased amounts of C18-C26 alcohols in yeast co-expressing CER4 and FAR1. Collectively, these findings demonstrate that FAO3 and FAO4b are functionally redundant in suppressing accumulation of primary alcohols and contributing to aldehyde production, which provides a missing and long-sought-after link between these two pathways in wax biosynthesis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Oxirredutases do Álcool , Álcoois/metabolismo , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/metabolismo , Alcanos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas Nucleares/metabolismo , Epiderme Vegetal/metabolismo , Ceras/metabolismo
5.
Int J Mol Sci ; 23(7)2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35409402

RESUMO

Plant epidermis contains atypical small chloroplasts. However, the physiological role of this organelle is unclear compared to that of large mesophyll chloroplasts, the well-known function of which is photosynthesis. Although knowledge of the involvement of chloroplasts in the plant immunity has been expanded to date, the differences between the epidermal and mesophyll chloroplasts are beyond the scope of this study. Given the role of the plant epidermis as a barrier to environmental stresses, including pathogen attacks, and the immune-related function of chloroplasts, plant defense research on epidermal chloroplasts is an emerging field. Recent studies have revealed the dynamic movements of epidermal chloroplasts in response to fungal and oomycete pathogens. Furthermore, epidermal chloroplast-associated proteins and cellular events that are tightly linked to epidermal resistance against pathogens have been reported. In this review, I have focused on the recent progress in epidermal chloroplast-mediated plant immunity.


Assuntos
Cloroplastos , Folhas de Planta , Proteínas de Cloroplastos/metabolismo , Cloroplastos/metabolismo , Epiderme Vegetal/metabolismo , Imunidade Vegetal , Folhas de Planta/metabolismo
6.
Sci Prog ; 105(2): 368504221094156, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35440237

RESUMO

Pogostemon Desf. includes a wide range of taxa found in subtropical and tropical areas. Few works, however, have studied microanatomical characteristics of Pogostemon species and as yet identified features of Pogostemon auricularius (L.) Hassk. Thus, in this paper, we examined the taxonomic implications of root, stem and leaf morphology for species P. auricularius collected from Quang Tri Province. Light microscopy was mainly used in our study. Qualitative characters like stem quadrangular, hirsute; leaves opposite, ovate, margin serrulate; calyx campanulate; corolla small with separate equal lobes have been found in P. auricularius. Epidermal anatomy on the aerial parts of the species like epidermal cell shape, anticlinal walls, trichomes types, stomata types and calcium oxalate crystals types were examined as well. Quantitative characters like the length and width of leaf blade and inflorescence; the size of oil droplet, stomata and calcium oxalate crystals measured provided taxonomic significance. Based on identifying morphological characteristics of P. auricularius, we aimed to contribute to the taxonomic investigation into the genus Pogostemon and give relative morphological and microanatomical features compared with other taxa.


Assuntos
Lamiaceae , Pogostemon , Oxalato de Cálcio , Lamiaceae/anatomia & histologia , Microscopia Eletrônica de Varredura , Epiderme Vegetal/anatomia & histologia
7.
Microsc Res Tech ; 85(6): 2162-2180, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35238102

RESUMO

The current study analyzed the epidermal morphology of Asparagaceae in detail and assessed its systematic importance. At the familial level, no consistent characteristics were found, but anticlinal wall and stomata morphology provided systematic information of different tribes, especially Ophiopogoneae and Polygonateae. In Ophiopogoneae, Liriope and Ophiopogon had similar epidermis, which implying a close relationship between them, and was also supported by related studies. The leaves of Polygonateae exhibited rounded and undulate anticlinal wall. Polygonatum arisanense var. formosanum had a rounded anticlinal wall, whereas other species exhibited undulate anticlinal walls. Different epidemis of Po. arisanense var. formosanum supported the variety treatment of Po. arisanense. The intergeneric relationship was also interpreted based on the anticlinal wall and stomata. Therefore, the epidermis could provide the systematic value of Asparagaceae. The present study also revealed the linkage of stomata and habitat types, though the adaptative significance of epidermal traits needs further study. RESEARCH HIGHLIGHTS: Anticlinal wall and stomatal morphology had systematic potential on tribal or generic levels of Asparagaceae. Stomatal types of Asparagaceae might be linked to environmental factors.


Assuntos
Asparagaceae , Epiderme Vegetal , Epiderme , Microscopia Eletrônica de Varredura , Epiderme Vegetal/anatomia & histologia , Folhas de Planta/anatomia & histologia , Estômatos de Plantas , Taiwan
8.
Microsc Res Tech ; 85(7): 2549-2557, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35322495

RESUMO

The genus Iris L., comprising approximately 210 species, is one of the most species-rich genera in the family Iridaceae. In this study, the first comprehensive leaf micromorphological characters of Korean irises were studied using light and scanning electron microscopy. Our objective was to evaluate the foliar micromorphological characteristics (namely epidermal cells, stomata types, and guard cell size) of Korean Iris taxa in a systematic context. All the investigated Korean Iris taxa had amphistomatic or hypostomatic leaves with anomocytic stomatal complexes. Guard cell length varied among species, ranging from 24.8 µm (I. rossii) to 56.0 µm (I. domestica). Although the presence of papillae on the outer periclinal wall is not of taxonomic significance, leaf margin pattern, guard cell size, and sunken stomata type were useful for species-level identification of Korean Iris species. The occurrence of polymorphic stomatal types was reported here for the first time, and the correlation between genome size and epidermal guard cell length was discussed.


Assuntos
Epiderme Vegetal , Estômatos de Plantas , Microscopia Eletrônica de Varredura , Epiderme Vegetal/anatomia & histologia , Folhas de Planta/anatomia & histologia , Estômatos de Plantas/anatomia & histologia , República da Coreia
9.
Physiol Plant ; 174(2): e13650, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35175634

RESUMO

Plant cuticle as hydrophobic barrier covers almost all aerial plant organs. Herein the cuticular chemical components and the transpiration of various organs of Chinese flowering cabbage (CFC) and Chinese kale (CK) were comprehensively characterized. Numerous species- and organ-specific differences in morphological, chemical, and physiological levels were found. The various organs were relatively smooth in surface for CFC but glaucous with hollow tube- and plate-type crystals for CK. The chemical composition of cuticular waxes were very-long chain n-alkanes, ketones, secondary alcohols with a prominent carbon chain of C29 in CK, primary alcohols dominated by C26 , and aldehydes prominently C30 in CFC. Cutin monomers accumulated with similar levels as waxes and were dominated by α,ω-dicarboxylic acids and fatty acids without added groups. The minimum water conductance differed considerably among species and various organs ranging between 8.9 × 10-5 (CK leaf) and 3.7 × 10-4  m s-1 (CFC leaf petiole). These differences in transpiration properties were proposed to be largely related to the cuticular chemicals in various organs and species. The presented results provide further insights to link the transpiration barrier functions with surface characteristics and cuticular chemicals.


Assuntos
Brassica , Epiderme Vegetal , Álcoois/análise , China , Epiderme Vegetal/química , Ceras/química
10.
Plant Cell Environ ; 45(4): 1157-1171, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35102563

RESUMO

The effect of contrasting environmental growth conditions (in vitro tissue culture, ex vitro acclimatisation, climate chamber, greenhouse and outdoor) on leaf development, cuticular wax composition, and foliar transpiration of detached leaves of the Populus × canescens clone 84 K were investigated. Our results show that total amounts of cuticular wax increased more than 10-fold when cultivated in different growth conditions, whereas qualitative wax composition did not change. With exception of plants directly taken from tissue culture showing rapid dehydration, rates of water loss (residual foliar transpiration) of intact but detached leaves were constant and independent from growth conditions and thus independent from increasing wax amounts. Since cuticular transpiration measured with isolated astomatous P. × canescens cuticles was identical to residual foliar transpiration rates of detached leaves, our results confirm that cuticular transpiration of P. × canescens leaves can be predicted with high accuracy from residual transpiration of detached leaves after stomatal closure. Our results convincingly show that more than 10-fold increased wax amounts in P. × canescens cuticles do not lead to decreased rates of residual (cuticular) transpiration.


Assuntos
Epiderme Vegetal , Transpiração Vegetal , Folhas de Planta , Água , Ceras
11.
Plant J ; 110(3): 658-672, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35106853

RESUMO

Plant cuticles are a mixture of crystalline and amorphous waxes that restrict the exchange of molecules between the plant and the atmosphere. The multicomponent nature of cuticular waxes complicates the study of the relationship between the physical and transport properties. Here, a model cuticle based on the epicuticular waxes of Petunia hybrida flower petals was formulated to test the effect of wax composition on diffusion of water and volatile organic compounds (VOCs). The model cuticle was composed of an n-tetracosane (C24 H50 ), 1-docosanol (C22 H45 OH), and 3-methylbutyl dodecanoate (C17 H34 O2 ), reflecting the relative chain length, functional groups, molecular arrangements, and crystallinity of the natural waxes. Molecular dynamics simulations were performed to obtain diffusion coefficients for compounds moving through waxes of varying composition. Simulated VOC diffusivities of the model system were found to highly correlate with in vitro measurements in isolated petunia cuticles. VOC diffusivity increased up to 30-fold in completely amorphous waxes, indicating a significant effect of crystallinity on cuticular permeability. The crystallinity of the waxes was highly dependent on the elongation of the lattice length and decrease in gap width between crystalline unit cells. Diffusion of water and higher molecular weight VOCs were significantly affected by alterations in crystalline spacing and lengths, whereas the low molecular weight VOCs were less affected. Comparison of measured diffusion coefficients from atomistic simulations and emissions from petunia flowers indicates that the role of the plant cuticle in the VOC emission network is attributed to the differential control on mass transfer of individual VOCs by controlling the composition, amount, and dynamics of scent emission.


Assuntos
Petunia , Compostos Orgânicos Voláteis , Células Epidérmicas , Epiderme Vegetal/química , Folhas de Planta/química , Compostos Orgânicos Voláteis/análise , Água , Ceras/química
12.
Nat Commun ; 13(1): 652, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115512

RESUMO

Stomatal opening requires the provision of energy in the form of ATP for proton pumping across the guard cell (GC) plasma membrane and for associated metabolic rearrangements. The source of ATP for GCs is a matter of ongoing debate that is mainly fuelled by controversies around the ability of GC chloroplasts (GCCs) to perform photosynthesis. By imaging compartment-specific fluorescent ATP and NADPH sensor proteins in Arabidopsis, we show that GC photosynthesis is limited and mitochondria are the main source of ATP. Unlike mature mesophyll cell (MC) chloroplasts, which are impermeable to cytosolic ATP, GCCs import cytosolic ATP through NUCLEOTIDE TRANSPORTER (NTT) proteins. GCs from ntt mutants exhibit impaired abilities for starch biosynthesis and stomatal opening. Our work shows that GCs obtain ATP and carbohydrates via different routes from MCs, likely to compensate for the lower chlorophyll contents and limited photosynthesis of GCCs.


Assuntos
Trifosfato de Adenosina/metabolismo , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Estômatos de Plantas/metabolismo , Amido/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Transporte Biológico , Cloroplastos/efeitos dos fármacos , Cloroplastos/efeitos da radiação , Citosol/metabolismo , Peróxido de Hidrogênio/farmacologia , Luz , Células do Mesofilo/citologia , Células do Mesofilo/metabolismo , Células do Mesofilo/efeitos da radiação , Microscopia Confocal , NADP/metabolismo , Proteínas de Transporte de Nucleotídeos/genética , Proteínas de Transporte de Nucleotídeos/metabolismo , Oxidantes/farmacologia , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Folhas de Planta/citologia , Folhas de Planta/metabolismo , Estômatos de Plantas/citologia , Estômatos de Plantas/fisiologia , Plantas Geneticamente Modificadas
13.
Science ; 375(6577): 177-182, 2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35025667

RESUMO

Messenger RNAs (mRNAs) function as mobile signals for cell-to-cell communication in multicellular organisms. The KNOTTED1 (KN1) homeodomain family transcription factors act non­cell autonomously to control stem cell maintenance in plants through cell-to-cell movement of their proteins and mRNAs through plasmodesmata; however, the mechanism of mRNA movement is largely unknown. We show that cell-to-cell movement of a KN1 mRNA requires ribosomal RNA­processing protein 44A (AtRRP44A), a subunit of the RNA exosome that processes or degrades diverse RNAs in eukaryotes. AtRRP44A can interact with plasmodesmata and mediates the cell-to-cell trafficking of KN1 mRNA, and genetic analysis indicates that AtRRP44A is required for the developmental functions of SHOOT MERISTEMLESS, an Arabidopsis KN1 homolog. Our findings suggest that AtRRP44A promotes mRNA trafficking through plasmodesmata to control stem cell­dependent processes in plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Complexo Multienzimático de Ribonucleases do Exossomo/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Plantas/genética , Plasmodesmos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Comunicação Celular , Complexo Multienzimático de Ribonucleases do Exossomo/genética , Proteínas de Homeodomínio/metabolismo , Meristema/genética , Meristema/fisiologia , Células do Mesofilo/metabolismo , Mutação , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Transporte Proteico , RNA de Plantas/genética , RNA de Plantas/metabolismo , Zea mays
15.
Microsc Res Tech ; 85(4): 1597-1610, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34888979

RESUMO

In the present study morpho-anatomical characterization of selected Rosaceae members distributed in District Lahore was performed. Light and scanning electron microscopy was used for systematic characterization of the selected 19 species. Distinguished morpho-anatomical features such as size and shape of epidermal cells, size and type of stomatal cells, size and shape of trichomes, oil droplets, and silica bodies were contrasted. Results reported remarkable variations which could be taxonomically useful in identification of these members. Polygonal epidermal cells were observed in Eriyobotraya japonica, Potentilla bifurca, Potentilla supina, and Prunus amygdalus. However, Prunus cerasus possessed irregular-shaped epidermal cells that can be distinguished from hexagonal epidermal cells of Prunus persica. Similarly, stomatal type varied among some members. Paracytic or perisocytic stomata were observed in E. japonica whereas P. bifurca observed paracytic and anisocytic stomata. Lengths of guard cells were also of variable sizes. The average length of guard cells ranged from 53 (52-54) µm to 74 (73-75) µm in abaxial view. Potentilla supina had biggest, while Rosmarinus officinalis had tiny guard cells. Trichomes were tubular, stellate, cylindrical, ribbon-like, glandular, and nonglandular. Silica bodies in the present investigation were bilobed, rounded, and oval-shaped. It is inferred that diverse anatomical features proved to be valuable taxonomic tools that could be fruitfully helpful in identification of plants at specific as well as generic level.


Assuntos
Epiderme Vegetal , Rosaceae , Microscopia Eletrônica de Varredura , Paquistão , Folhas de Planta , Estômatos de Plantas
16.
Microsc Res Tech ; 85(3): 980-995, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34726301

RESUMO

The present study was performed to provide a detailed explanation of leaf epidermal anatomy and pollen micromorphological features of selected species of family Apiaceae from Chitral, eastern Hindu Kush region as the basis of forthcoming studies. In the present article pollen morphology of eight species and foliar epidermal of seven species of family Apiaceae have been examined through microscopic techniques. In results two types of pollen prolate (five species) and perprolate (three species) with three colpi have been recorded. The exine ornamentation was found to be regulate, striate, and cerebroid. Largest pollen was found in Heracleum leucocarpum with the polar diameter of 43.25 µm and equatorial diameter of 21.6 µm. Smallest pollen was observed in Elaeosticta chitralica with the polar diameter of 18.4 µm. The P/E ratio varied from 1.59 to 2.16. Regarding to foliar epidermal anatomy, three types of epidermal cells including rectangular, irregular, and polygonal with variation in anticlinal wall pattern were determined. In the selected species three kinds of stomata comprising anisocytic, anomocytic, and paracytic type were reported in the current research. The size of epidermal cells ranged from 106 × 42.50 µm in Bupleurum falcatum subsp. cernuum and 77.25 × 26.35 µm in Prangos pabularia in adaxial surface. Largest stomatal complex was found in Prangos pabularia both in adaxial 33.55 × 20.05 µm and abaxial 50.25 × 39.40 µm. All the observed quantitative and qualitative features of the species were proved to be useful in the delimitation of species at generic and species level.


Assuntos
Apiaceae , Epiderme Vegetal , Microscopia Eletrônica de Varredura , Paquistão , Epiderme Vegetal/ultraestrutura , Folhas de Planta
17.
Protoplasma ; 259(1): 203-215, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33948739

RESUMO

The genus Mimosa Linnaeus (Leguminosae) comprises more than 530 species, being one of the most diversified genera in the family. A vast morphologic variability has been described at all infrageneric levels. Considering stomata description, a very low proportion of species have been studied in the genus, and the description was limited to stomata types, but not to variation in the disposition of subsidiary cells. Here we analyze type, length, and distribution of stomatic complexes in 19 taxa of Mimosa subseries Dolentes and subseries Brevipedes, a high variability taxonomic complex, as well as their density on both foliar faces and epidermic pavement cell morphology. We found four different stomatal types, 2 distribution types, and 3 epidermic pavement cell shapes. Some of these features are taxonomically relevant at infraspecific levels, since it adds important information for the separation of the taxa, but also questions supraspecific taxonomic groups of previous proposals of the genus. We also hypothesized about the origin of the variation of some stomata features in relation to ecological and ploidy-level variability in this complex.


Assuntos
Fabaceae , Mimosa , Células Epidérmicas , Epiderme Vegetal , Estômatos de Plantas
18.
Plant Cell ; 34(1): 209-227, 2022 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-34623438

RESUMO

As the outermost layer of plants, the epidermis serves as a critical interface between plants and the environment. During leaf development, the differentiation of specialized epidermal cell types, including stomatal guard cells, pavement cells, and trichomes, occurs simultaneously, each providing unique and pivotal functions for plant growth and survival. Decades of molecular-genetic and physiological studies have unraveled key players and hormone signaling specifying epidermal differentiation. However, most studies focus on only one cell type at a time, and how these distinct cell types coordinate as a unit is far from well-comprehended. Here we provide a review on the current knowledge of regulatory mechanisms underpinning the fate specification, differentiation, morphogenesis, and positioning of these specialized cell types. Emphasis is given to their shared developmental origins, fate flexibility, as well as cell cycle and hormonal controls. Furthermore, we discuss computational modeling approaches to integrate how mechanical properties of individual epidermal cell types and entire tissue/organ properties mutually influence each other. We hope to illuminate the underlying mechanisms coordinating the cell differentiation that ultimately generate a functional leaf epidermis.


Assuntos
Diferenciação Celular , Desenvolvimento Vegetal , Epiderme Vegetal/fisiologia , Folhas de Planta/fisiologia
19.
Plant Physiol ; 188(1): 318-331, 2022 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-34618124

RESUMO

Petals of the monocot Phalaenopsis aphrodite (Orchidaceae) possess conical epidermal cells on their adaxial surfaces, and a large amount of cuticular wax is deposited on them to serve as a primary barrier against biotic and abiotic stresses. It has been widely reported that subgroup 9A members of the R2R3-MYB gene family, MIXTA and MIXTA-like in eudicots, act to regulate the differentiation of conical epidermal cells. However, the molecular pathways underlying conical epidermal cell development and cuticular wax biosynthesis in monocot petals remain unclear. Here, we characterized two subgroup 9A R2R3-MYB genes, PaMYB9A1 and PaMYB9A2 (PaMYB9A1/2), from P. aphrodite through the transient overexpression of their coding sequences and corresponding chimeric repressors in developing petals. We showed that PaMYB9A1/2 function to coordinate conical epidermal cell development and cuticular wax biosynthesis. In addition, we identified putative targets of PaMYB9A1/2 through comparative transcriptome analyses, revealing that PaMYB9A1/2 acts to regulate the expression of cell wall-associated and wax biosynthetic genes. Furthermore, a chemical composition analysis of cuticular wax showed that even-chain n-alkanes and odd-chain primary alcohols are the main chemical constituents of cuticular wax deposited on petals, which is inconsistent with the well-known biosynthetic pathways of cuticular wax, implying a distinct biosynthetic pathway occurring in P. aphrodite flowers. These results reveal that the function of subgroup 9A R2R3-MYB family genes in regulating the differentiation of epidermal cells is largely conserved in monocots and dicots. Furthermore, both PaMYB9A1/2 have evolved additional functions controlling the biosynthesis of cuticular wax.


Assuntos
Diferenciação Celular/genética , Proliferação de Células/genética , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/genética , Orchidaceae/metabolismo , Epiderme Vegetal/genética , Epiderme Vegetal/metabolismo , Ceras/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Morfogênese/genética , Plantas Geneticamente Modificadas
20.
Microsc Res Tech ; 85(1): 135-148, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34331492

RESUMO

In current study, 22 herbaceous plant specimens have been examined with the help of light microscope to carry out leaf epidermal anatomy. Foliar micro-morphology of herbaceous plants from Tilla Jogian, Jhelum Pakistan was held first time. The plants were collected from different parts of Tilla Jogian at different elevations. The main objective of the study is to use this information as an aid in plant taxonomy. Significant variations were observed in both qualitative and quantitative features. With the help of microscopy significant variations in characters like stomata size, number, epidermal cell size, shape and number, guard cell size, trichomes, and subsidiary cells were recorded. On the basis of these findings, light microscopy of leaf epidermal anatomical features holds great interest for taxonomists to identify complete taxa. Foliar epidermal anatomy of herbaceous flora serves as baseline data along with taxonomical data and can be helpful in demarcation and limitation of nearly associated taxa to gain better use of anatomical characters.


Assuntos
Epiderme Vegetal , Estômatos de Plantas , Microscopia Eletrônica de Varredura , Paquistão , Folhas de Planta , Plantas
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