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1.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204559

RESUMO

Recent data indicate that modifications to carotenoid biosynthesis pathway in plants alter the expression of genes affecting chemical composition of the cell wall. Phytoene synthase (PSY) is a rate limiting factor of carotenoid biosynthesis and it may exhibit species-specific and organ-specific roles determined by the presence of psy paralogous genes, the importance of which often remains unrevealed. Thus, the aim of this work was to elaborate the roles of two psy paralogs in a model system and to reveal biochemical changes in the cell wall of psy knockout mutants. For this purpose, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR associated (Cas9) proteins (CRISPR/Cas9) vectors were introduced to carotenoid-rich carrot (Daucus carota) callus cells in order to induce mutations in the psy1 and psy2 genes. Gene sequencing, expression analysis, and carotenoid content analysis revealed that the psy2 gene is critical for carotenoid biosynthesis in this model and its knockout blocks carotenogenesis. The psy2 knockout also decreased the expression of the psy1 paralog. Immunohistochemical staining of the psy2 mutant cells showed altered composition of arabinogalactan proteins, pectins, and extensins in the mutant cell walls. In particular, low-methylesterified pectins were abundantly present in the cell walls of carotenoid-rich callus in contrast to the carotenoid-free psy2 mutant. Transmission electron microscopy revealed altered plastid transition to amyloplasts instead of chromoplasts. The results demonstrate for the first time that the inhibited biosynthesis of carotenoids triggers the cell wall remodelling.


Assuntos
Vias Biossintéticas/genética , Sistemas CRISPR-Cas , Carotenoides/metabolismo , Parede Celular/metabolismo , Daucus carota/fisiologia , Edição de Genes , Sequência de Bases , Parede Celular/ultraestrutura , Daucus carota/ultraestrutura , Marcação de Genes , Genes de Plantas , Vetores Genéticos/genética , Mutação , Fenótipo , Plastídeos/genética , Plastídeos/ultraestrutura
2.
Int J Mol Sci ; 22(14)2021 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-34299279

RESUMO

Modern light microscopy imaging techniques have substantially advanced our knowledge about the ultrastructure of plant cells and their organelles. Laser-scanning microscopy and digital light microscopy imaging techniques, in general-in addition to their high sensitivity, fast data acquisition, and great versatility of 2D-4D image analyses-also opened the technical possibilities to combine microscopy imaging with spectroscopic measurements. In this review, we focus our attention on differential polarization (DP) imaging techniques and on their applications on plant cell walls and chloroplasts, and show how these techniques provided unique and quantitative information on the anisotropic molecular organization of plant cell constituents: (i) We briefly describe how laser-scanning microscopes (LSMs) and the enhanced-resolution Re-scan Confocal Microscope (RCM of Confocal.nl Ltd. Amsterdam, Netherlands) can be equipped with DP attachments-making them capable of measuring different polarization spectroscopy parameters, parallel with the 'conventional' intensity imaging. (ii) We show examples of different faces of the strong anisotropic molecular organization of chloroplast thylakoid membranes. (iii) We illustrate the use of DP imaging of cell walls from a variety of wood samples and demonstrate the use of quantitative analysis. (iv) Finally, we outline the perspectives of further technical developments of micro-spectropolarimetry imaging and its use in plant cell studies.


Assuntos
Células Vegetais/ultraestrutura , Anisotropia , Parede Celular/ultraestrutura , Cloroplastos/ultraestrutura , Microscopia Confocal/métodos , Microscopia de Polarização/métodos , Tilacoides/ultraestrutura
3.
Nat Commun ; 12(1): 4639, 2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-34330922

RESUMO

The silica cell wall of diatoms, a widespread group of unicellular microalgae, is an exquisite example for the ability of organisms to finely sculpt minerals under strict biological control. The prevailing paradigm for diatom silicification is that this is invariably an intracellular process, occurring inside specialized silica deposition vesicles that are responsible for silica precipitation and morphogenesis. Here, we study the formation of long silicified extensions that characterize many diatom species. We use cryo-electron tomography to image silica formation in situ, in 3D, and at a nanometer-scale resolution. Remarkably, our data suggest that, contradictory to the ruling paradigm, these intricate structures form outside the cytoplasm. In addition, the formation of these silica extensions is halted at low silicon concentrations that still support the formation of other cell wall elements, further alluding to a different silicification mechanism. The identification of this unconventional strategy expands the suite of mechanisms that diatoms use for silicification.


Assuntos
Parede Celular/metabolismo , Diatomáceas/metabolismo , Espaço Extracelular/metabolismo , Dióxido de Silício/metabolismo , Ciclo Celular , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Parede Celular/ultraestrutura , Microscopia Crioeletrônica/métodos , Diatomáceas/ultraestrutura , Tomografia com Microscopia Eletrônica/métodos , Microscopia Eletrônica de Varredura/métodos , Microscopia Eletrônica de Transmissão/métodos , Microtúbulos/metabolismo , Microtúbulos/ultraestrutura
4.
Food Chem ; 361: 130034, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34091401

RESUMO

Fermentation often degrades the cell wall of dark tea, changes the carbohydrate components in the cell wall of tea, and thus affects the quality of tea. However, the lack of ultrastructural details limits our knowledge on the effect of fermentation on tea cell walls. Morphological studies of cell structures are important; thus, the cell wall of Liupao tea was analyzed under transmission electron microscopy for the first time, and the effects of different raw materials and fermentation methods on the cell wall and main carbohydrates of tea were compared. Overall, fermentation degrades the cell wall of Liupao tea under the action of microorganisms. Interestingly, the middle lamella degrades obviously, whereas the primary wall is complete. The decrease in hemicellulose and increase in water-soluble pectin (WSP) were remarkable, whereas the changes in cellulose and WSP were considerably correlated with the increase in tea polysaccharide (TPS). The results suggest that cell wall degradation might be related to the increase in TPS.


Assuntos
Parede Celular/metabolismo , Fermentação , Polissacarídeos , Chá/química , Camellia sinensis/química , Parede Celular/ultraestrutura , China , Microscopia Eletrônica de Transmissão , Chá/metabolismo , Chá/ultraestrutura
5.
Int J Mol Sci ; 22(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066340

RESUMO

Watercore is a physiological disorder that commonly occurs in sand pear cultivars. The typical symptom of watercore tissue is transparency, and it is often accompanied by browning, breakdown and a bitter taste during fruit ripening. To better understand the molecular mechanisms of watercore affecting fruit quality, this study performed transcriptome and metabolome analyses on watercore pulp from "Akibae" fruit 125 days after flowering. The present study found that the "Akibae" pear watercore pulp contained higher sorbitol and sucrose than healthy fruit. Moreover, the structure of the cell wall was destroyed, and the content of pectin, cellulose and hemicellulose was significantly decreased. In addition, the content of ethanol and acetaldehyde was significantly increased, and the content of polyphenol was significantly decreased. Watercore induced up-regulated expression levels of sorbitol synthesis-related (sorbitol-6-phosphate dehydrogenase, S6PDH) and sucrose synthesis-related genes (sucrose synthesis, SS), whereas it inhibited the expression of sorbitol decomposition-related genes (sorbitol dehydrogenase, SDH) and sorbitol transport genes (sorbitol transporter, SOT). Watercore also strongly induced increased expression levels of cell wall-degrading enzymes (polygalactosidase, PG; ellulase, CX; pectin methylesterase, PME), as well as ethanol synthesis-related (alcohol dehydrogenase, ADH), acetaldehyde synthesis-related (pyruvate decarboxylase, PDC) and polyphenol decomposition-related genes (polyphenol oxidase, PPO). Moreover, the genes that are involved in ethylene (1-aminocyclopropane- 1-carboxylate oxidase, ACO; 1-aminocyclopropane- 1-carboxylate synthase, ACS) and abscisic acid (short-chain alcohol dehydrogenase, SDR; aldehyde oxidase, AAO) synthesis were significantly up-regulated. In addition, the bitter tasting amino acids, alkaloids and polyphenols were significantly increased in watercore tissue. Above all, these findings suggested that the metabolic disorder of sorbitol and sucrose can lead to an increase in plant hormones (abscisic acid and ethylene) and anaerobic respiration, resulting in aggravated fruit rot and the formation of bitter substances.


Assuntos
Frutas/genética , Frutas/metabolismo , Metaboloma/genética , Doenças das Plantas/genética , Pyrus/genética , Pyrus/metabolismo , Transcriptoma/genética , Ácido Abscísico/metabolismo , Acetaldeído/análise , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Etanol/análise , Etilenos/metabolismo , Frutas/ultraestrutura , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Modelos Biológicos , Fenóis/análise , Pyrus/ultraestrutura , Análise de Sequência de RNA , Paladar
6.
Fungal Genet Biol ; 153: 103575, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34033880

RESUMO

Hospital infections caused by the opportunistic fungus Candida albicans are increasingly common and life threatening. The first line of defense consists of administering antifungal drugs such as azoles including fluconazole that prevent ergosterol biosynthesis. C. albicans is rapidly developing resistance towards antifungal drugs through various mechanisms including mutations in ERG11 which is a gene involved in the ergosterol biosynthesis pathway. These mutations prevent the binding of the drug and inactivate ergosterol synthesis. Alternatively, upregulation of cell membrane ergosterol content generates resistance by countering the effect of the drug. In this study we sequenced the ERG11 gene in 6 fluconazole sensitive and 8 fluconazole resistant C. albicans isolates recovered from clinical settings in Lebanon and quantified the ergosterol content of their plasma membranes to identify mechanisms linked to fluconazole resistance. A number of pathogenicity attributes were also analyzed to determine any correlation with fluconazole resistance. Our results revealed an increase in ergosterol content in the fluconazole resistant isolates. In addition, we identified both novel and previously reported amino acid substitutions in ERG11 as well as frameshift mutations that might contribute to resistance. The fluconazole resistant isolates did not exhibit an increased virulence potential in a mouse model of systemic infection and showed decreased in vitro potential to form biofilms. No discrepancy between drug resistant and sensitive isolates to cell surface disrupting agents was observed. This approach is the first of its kind to be carried out in Lebanon to identify possible mechanisms and phenotypes of drug resistant C. albicans isolates.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/patogenicidade , Candidíase/microbiologia , Fluconazol/farmacologia , Genes Fúngicos , Substituição de Aminoácidos , Animais , Biofilmes/crescimento & desenvolvimento , Candida albicans/genética , Candida albicans/crescimento & desenvolvimento , Parede Celular/ultraestrutura , Quitina/análise , Infecção Hospitalar/microbiologia , Farmacorresistência Fúngica , Ergosterol/metabolismo , Feminino , Mutação da Fase de Leitura , Proteínas Fúngicas/genética , Humanos , Líbano , Camundongos , Virulência
7.
Nat Commun ; 12(1): 2583, 2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-33972516

RESUMO

Quantitative micromechanical characterization of single cells and multicellular tissues or organisms is of fundamental importance to the study of cellular growth, morphogenesis, and cell-cell interactions. However, due to limited manipulation capabilities at the microscale, systems used for mechanical characterizations struggle to provide complete three-dimensional coverage of individual specimens. Here, we combine an acoustically driven manipulation device with a micro-force sensor to freely rotate biological samples and quantify mechanical properties at multiple regions of interest within a specimen. The versatility of this tool is demonstrated through the analysis of single Lilium longiflorum pollen grains, in combination with numerical simulations, and individual Caenorhabditis elegans nematodes. It reveals local variations in apparent stiffness for single specimens, providing previously inaccessible information and datasets on mechanical properties that serve as the basis for biophysical modelling and allow deeper insights into the biomechanics of these living systems.


Assuntos
Imageamento Tridimensional/métodos , Micromanipulação/instrumentação , Micromanipulação/métodos , Microscopia de Força Atômica/métodos , Análise de Célula Única/instrumentação , Análise de Célula Única/métodos , Acústica , Animais , Fenômenos Biomecânicos , Caenorhabditis elegans/anatomia & histologia , Caenorhabditis elegans/citologia , Parede Celular/ultraestrutura , Lilium/citologia , Microscopia Eletrônica de Varredura , Morfogênese , Células Vegetais , Pólen/citologia , Pólen/ultraestrutura
8.
Nat Commun ; 12(1): 2987, 2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-34016967

RESUMO

The elongasome, or Rod system, is a protein complex that controls cell wall formation in rod-shaped bacteria. MreC is a membrane-associated elongasome component that co-localizes with the cytoskeletal element MreB and regulates the activity of cell wall biosynthesis enzymes, in a process that may be dependent on MreC self-association. Here, we use electron cryo-microscopy and X-ray crystallography to determine the structure of a self-associated form of MreC from Pseudomonas aeruginosa in atomic detail. MreC monomers interact in head-to-tail fashion. Longitudinal and lateral interfaces are essential for oligomerization in vitro, and a phylogenetic analysis of proteobacterial MreC sequences indicates the prevalence of the identified interfaces. Our results are consistent with a model where MreC's ability to alternate between self-association and interaction with the cell wall biosynthesis machinery plays a key role in the regulation of elongasome activity.


Assuntos
Proteínas de Bactérias/metabolismo , Parede Celular/metabolismo , Pseudomonas aeruginosa/metabolismo , Sequência de Aminoácidos/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/ultraestrutura , Parede Celular/ultraestrutura , Sequência Conservada/genética , Microscopia Crioeletrônica , Cristalografia por Raios X , Mutagênese , Filogenia , Conformação Proteica em alfa-Hélice/genética , Conformação Proteica em Folha beta/genética , Domínios Proteicos/genética , Multimerização Proteica , Pseudomonas aeruginosa/citologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/ultraestrutura , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura
9.
Science ; 372(6543): 706-711, 2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-33986175

RESUMO

Plants have evolved complex nanofibril-based cell walls to meet diverse biological and physical constraints. How strength and extensibility emerge from the nanoscale-to-mesoscale organization of growing cell walls has long been unresolved. We sought to clarify the mechanical roles of cellulose and matrix polysaccharides by developing a coarse-grained model based on polymer physics that recapitulates aspects of assembly and tensile mechanics of epidermal cell walls. Simple noncovalent binding interactions in the model generate bundled cellulose networks resembling that of primary cell walls and possessing stress-dependent elasticity, stiffening, and plasticity beyond a yield threshold. Plasticity originates from fibril-fibril sliding in aligned cellulose networks. This physical model provides quantitative insight into fundamental questions of plant mechanobiology and reveals design principles of biomaterials that combine stiffness with yielding and extensibility.


Assuntos
Parede Celular/fisiologia , Parede Celular/ultraestrutura , Celulose , Células Vegetais/ultraestrutura , Epiderme Vegetal/ultraestrutura , Polissacarídeos , Fenômenos Biomecânicos , Configuração de Carboidratos , Celulose/química , Elasticidade , Modelos Biológicos , Simulação de Dinâmica Molecular , Cebolas/ultraestrutura , Estresse Mecânico
10.
J Mol Biol ; 433(13): 167004, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-33891903

RESUMO

The bacterial flagellum consists of a long extracellular filament that is rotated by a motor embedded in the cell envelope. While flagellar assembly has been extensively studied,1 the disassembly process remains less well understood. In addition to the programmed flagellar ejection that occurs during the life cycle of Caulobacter crescentus, we and others have recently shown that many bacterial species lose their flagella under starvation conditions, leaving relic structures in the outer membrane.2-7 However, it remains unknown whether the programmed flagellar ejection of C. crescentus leaves similar relics or not. Here, we imaged the various stages of the C. crescentus life cycle using electron cryo-tomography (cryo-ET) and found that flagellar relic subcomplexes, akin to those produced in the starvation-induced process, remain as a result of flagellar ejection during cell development. This similarity suggests that the programmed flagellar ejection of C. crescentus might share a common evolutionary path with the more general, and likely more ancient,3 starvation-related flagellar loss.


Assuntos
Caulobacter crescentus/fisiologia , Parede Celular/metabolismo , Flagelos/fisiologia , Lipopolissacarídeos/metabolismo , Peptidoglicano/metabolismo , Corpos Basais/fisiologia , Corpos Basais/ultraestrutura , Caulobacter crescentus/metabolismo , Caulobacter crescentus/ultraestrutura , Parede Celular/ultraestrutura , Tomografia com Microscopia Eletrônica/métodos , Fímbrias Bacterianas/fisiologia , Fímbrias Bacterianas/ultraestrutura , Flagelos/ultraestrutura
11.
Nat Commun ; 12(1): 2448, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33907196

RESUMO

Despite the central role of division in bacterial physiology, how division proteins work together as a nanoscale machine to divide the cell remains poorly understood. Cell division by cell wall synthesis proteins is guided by the cytoskeleton protein FtsZ, which assembles at mid-cell as a dense Z-ring formed of treadmilling filaments. However, although FtsZ treadmilling is essential for cell division, the function of FtsZ treadmilling remains unclear. Here, we systematically resolve the function of FtsZ treadmilling across each stage of division in the Gram-positive model organism Bacillus subtilis using a combination of nanofabrication, advanced microscopy, and microfluidics to measure the division-protein dynamics in live cells with ultrahigh sensitivity. We find that FtsZ treadmilling has two essential functions: mediating condensation of diffuse FtsZ filaments into a dense Z-ring, and initiating constriction by guiding septal cell wall synthesis. After constriction initiation, FtsZ treadmilling has a dispensable function in accelerating septal constriction rate. Our results show that FtsZ treadmilling is critical for assembling and initiating the bacterial cell division machine.


Assuntos
Bacillus subtilis/metabolismo , Proteínas de Bactérias/metabolismo , Parede Celular/metabolismo , Proteínas do Citoesqueleto/metabolismo , Guanosina Trifosfato/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/crescimento & desenvolvimento , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Divisão Celular , Parede Celular/ultraestrutura , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/genética , Expressão Gênica , Hidrólise , Técnicas Analíticas Microfluídicas , Modelos Biológicos , Transporte Proteico
12.
Dev Cell ; 56(7): 933-948, 2021 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-33761322

RESUMO

Organelles of the plant cell cooperate to synthesize and secrete a strong yet flexible polysaccharide-based extracellular matrix: the cell wall. Cell wall composition varies among plant species, across cell types within a plant, within different regions of a single cell wall, and in response to intrinsic or extrinsic signals. This diversity in cell wall makeup is underpinned by common cellular mechanisms for cell wall production. Cellulose synthase complexes function at the plasma membrane and deposit their product into the cell wall. Matrix polysaccharides are synthesized by a multitude of glycosyltransferases in hundreds of mobile Golgi stacks, and an extensive set of vesicle trafficking proteins govern secretion to the cell wall. In this review, we discuss the different subcellular locations at which cell wall synthesis occurs, review the molecular mechanisms that control cell wall biosynthesis, and examine how these are regulated in response to different perturbations to maintain cell wall homeostasis.


Assuntos
Parede Celular/metabolismo , Células Vegetais/metabolismo , Membrana Celular/enzimologia , Membrana Celular/metabolismo , Parede Celular/química , Parede Celular/ultraestrutura , Endocitose , Retículo Endoplasmático/metabolismo , Glucosiltransferases/metabolismo , Complexo de Golgi/metabolismo , Homeostase , Células Vegetais/enzimologia , Células Vegetais/ultraestrutura , Polissacarídeos/biossíntese
13.
Int J Mol Sci ; 22(3)2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-33573354

RESUMO

Cytokinesis is accomplished in higher plants by the phragmoplast, creating and conducting the cell plate to separate daughter nuclei by a new cell wall. The microtubule-severing enzyme p60-katanin plays an important role in the centrifugal expansion and timely disappearance of phragmoplast microtubules. Consequently, aberrant structure and delayed expansion rate of the phragmoplast have been reported to occur in p60-katanin mutants. Here, the consequences of p60-katanin malfunction in cell plate/daughter wall formation were investigated by transmission electron microscopy (TEM), in root cells of the fra2 Arabidopsis thaliana loss-of-function mutant. In addition, deviations in the chemical composition of cell plate/new cell wall were identified by immunolabeling and confocal microscopy. It was found that, apart from defective phragmoplast microtubule organization, cell plates/new cell walls also appeared faulty in structure, being unevenly thick and perforated by large gaps. In addition, demethylesterified homogalacturonans were prematurely present in fra2 cell plates, while callose content was significantly lower than in the wild type. Furthermore, KNOLLE syntaxin disappeared from newly formed cell walls in fra2 earlier than in the wild type. Taken together, these observations indicate that delayed cytokinesis, due to faulty phragmoplast organization and expansion, results in a loss of synchronization between cell plate growth and its chemical maturation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Parede Celular/metabolismo , Citocinese/fisiologia , Katanina/metabolismo , Arabidopsis/citologia , Arabidopsis/ultraestrutura , Proteínas de Arabidopsis/genética , Parede Celular/ultraestrutura , Katanina/genética , Microscopia Eletrônica de Transmissão , Microtúbulos/metabolismo , Microtúbulos/ultraestrutura , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Raízes de Plantas/ultraestrutura , Plantas Geneticamente Modificadas , Proteínas Qa-SNARE/metabolismo
14.
Parasit Vectors ; 14(1): 81, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33494800

RESUMO

BACKGROUND: Nosema bombycis is a unicellular eukaryotic pathogen of the silkworm, Bombyx mori, and is an economic and occupational hazard in the silkworm industry. Because of its long incubation period and horizontal and vertical transmission, it is subject to quarantine measures in sericulture production. The microsporidian life-cycle includes a dormant extracellular phase and intracellular proliferation phase, with the proliferation period being the most active period. This latter period lacks spore wall protection and may be the most susceptible stage for control. METHODS: In order to find suitable target for the selective breeding of N. bombycis-resistant silkworm strains, we screen highly expressed membrane proteins from the transcriptome data of N. bombycis. The subcellular localization of the candidate protein was verified by Indirect immunofluorescence analysis (IFA) and immunoelectron microscopy (IEM), and its role in N. bombycis proliferation was verified by RNAi. RESULTS: The N. bombycis protein (NBO_76g0014) was identified as a transmembrane protein and named NbTMP1. It is homologous with hypothetical proteins NGRA_1734 from Nosema granulosis. NbTMP1 has a transmembrane region of 23 amino acids at the N-terminus. Indirect immunofluorescence analysis (IFA) results suggest that NbTMP1 is secreted on the plasma membrane as the spores develop. Western blot and qRT-PCR analysis showed that NbTMP1 was expressed in all developmental stages of N. bombycis in infected cells and in the silkworm midgut. Downregulation of NbTMP1 expression resulted in significant inhibition of N. bombycis proliferation. CONCLUSIONS: We confirmed that NbTMP1 is a membrane protein of N. bombycis. Reduction of the transcription level of NbTMP1 significantly inhibited N. bombycis proliferation, and this protein may be a target for the selective breeding of N. bombycis-resistant silkworm strains.


Assuntos
Bombyx/microbiologia , Proteínas de Membrana , Nosema/metabolismo , Animais , Bombyx/metabolismo , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Técnica Indireta de Fluorescência para Anticorpo , Proteínas Fúngicas/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Microscopia Imunoeletrônica , Microsporídios/metabolismo , Nosema/ultraestrutura , Interferência de RNA , Esporos Fúngicos/metabolismo , Esporos Fúngicos/ultraestrutura
15.
Genes (Basel) ; 12(2)2021 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499195

RESUMO

Cell wall integrity control in plants involves multiple signaling modules that are mostly defined by genetic interactions. The putative co-receptors FEI1 and FEI2 and the extracellular glycoprotein FLA4 present the core components of a signaling pathway that acts in response to environmental conditions and insults to cell wall structure to modulate the balance of various growth regulators and, ultimately, to regulate the performance of the primary cell wall. Although the previously established genetic interactions are presently not matched by intermolecular binding studies, numerous receptor-like molecules that were identified in genome-wide interaction studies potentially contribute to the signaling machinery around the FLA4-FEI core. Apart from its function throughout the model plant Arabidopsis thaliana for the homeostasis of growth and stress responses, the FLA4-FEI pathway might support important agronomic traits in crop plants.


Assuntos
Moléculas de Adesão Celular/metabolismo , Parede Celular/metabolismo , Células Vegetais/fisiologia , Proteínas de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Moléculas de Adesão Celular/genética , Parede Celular/ultraestrutura , Celulose/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Pectinas/metabolismo , Desenvolvimento Vegetal/genética , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética
16.
Cells ; 10(1)2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33440743

RESUMO

Plant cell walls (PCWs) form the outer barrier of cells that give the plant strength and directly interact with the environment and other cells in the plant. PCWs are composed of several polysaccharides, of which cellulose forms the main fibrillar network. Enmeshed between these fibrils of cellulose are non-cellulosic polysaccharides (NCPs), pectins, and proteins. This study investigates the sequence, timing, patterning, and architecture of cell wall polysaccharide regeneration in suspension culture cells (SCC) of the grass species Lolium multiflorum (Lolium). Confocal, superresolution, and electron microscopies were used in combination with cytochemical labeling to investigate polysaccharide deposition in SCC after protoplasting. Cellulose was the first polysaccharide observed, followed shortly thereafter by (1,3;1,4)-ß-glucan, which is also known as mixed-linkage glucan (MLG), arabinoxylan (AX), and callose. Cellulose formed fibrils with AX and produced a filamentous-like network, whereas MLG formed punctate patches. Using colocalization analysis, cellulose and AX were shown to interact during early stages of wall generation, but this interaction reduced over time as the wall matured. AX and MLG interactions increased slightly over time, but cellulose and MLG were not seen to interact. Callose initially formed patches that were randomly positioned on the protoplast surface. There was no consistency in size or location over time. The architecture observed via superresolution microscopy showed similarities to the biophysical maps produced using atomic force microscopy and can give insight into the role of polysaccharides in PCWs.


Assuntos
Parede Celular/metabolismo , Celulose/metabolismo , Lolium/citologia , Regeneração , Xilanos/metabolismo , beta-Glucanas/metabolismo , Parede Celular/ultraestrutura , Células Cultivadas , Lolium/ultraestrutura , Protoplastos/metabolismo , Suspensões , Fatores de Tempo
17.
Plant Cell Rep ; 40(2): 393-403, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33388893

RESUMO

KEY MESSAGE: Resistance conferred by the Cre8 locus of wheat prevents cereal cyst nematode feeding sites from reaching and invading root metaxylem vessels. Cyst nematodes develop syncytial feeding sites within plant roots. The success of these sites is affected by host plant resistance. In wheat (Triticum aestivum L.), 'Cre' loci affect resistance against the cereal cyst nematode (CCN) Heterodera avenae. To investigate how one of these loci (Cre8, on chromosome 6B) confers resistance, CCN-infected root tissue from susceptible (-Cre8) and resistant (+Cre8) wheat plants was examined using confocal microscopy and laser ablation tomography. Confocal analysis of transverse sections showed that feeding sites in the roots of -Cre8 plants were always adjacent to metaxylem vessels, contained many intricate 'web-like' cell walls, and sometimes 'invaded' metaxylem vessels. In contrast, feeding sites in the roots of +Cre8 plants were usually not directly adjacent to metaxylem vessels, had few inner cell walls and did not 'invade' metaxylem vessels. Models based on data from laser ablation tomography confirmed these observations. Confocal analysis of longitudinal sections revealed that CCN-induced xylem modification that had previously been reported for susceptible (-Cre8) wheat plants is less extreme in resistant (+Cre8) plants. Application of a lignin-specific stain revealed that secondary thickening around xylem vessels in CCN-infected roots was greater in +Cre8 plants than in -Cre8 plants. Collectively, these results indicate that Cre8 resistance in wheat acts by preventing cyst nematode feeding sites from reaching and invading root metaxylem vessels.


Assuntos
Resistência à Doença/genética , Doenças das Plantas/parasitologia , Proteínas de Plantas/metabolismo , Triticum/parasitologia , Tylenchida/fisiologia , Animais , Parede Celular/parasitologia , Parede Celular/ultraestrutura , Suscetibilidade a Doenças , Loci Gênicos , Imageamento Tridimensional , Doenças das Plantas/prevenção & controle , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/parasitologia , Raízes de Plantas/ultraestrutura , Triticum/genética , Triticum/ultraestrutura , Xilema/genética , Xilema/parasitologia , Xilema/ultraestrutura
18.
Plant Cell Rep ; 40(3): 437-459, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33389046

RESUMO

KEY MESSAGE: Cell wall plasticity plays a very crucial role in vegetative and reproductive development of rice under drought and is a highly potential trait for improving rice yield under drought. Drought is a major constraint in rice (Oryza sativa L.) cultivation severely affecting all developmental stages, with the reproductive stage being the most sensitive. Rice plants employ multiple strategies to cope with drought, in which modification in cell wall dynamics plays a crucial role. Over the years, significant progress has been made in discovering the cell wall-specific genomic resources related to drought tolerance at vegetative and reproductive stages of rice. However, questions remain about how the drought-induced changes in cell wall made by these genomic resources potentially influence the vegetative and reproductive development of rice. The possibly major candidate genes underlying the function of quantitative trait loci directly or indirectly associated with the cell wall plasticization-mediated drought tolerance of rice might have a huge promise in dissecting the putative genomic regions associated with cell wall plasticity under drought. Furthermore, engineering the drought tolerance of rice using cell wall-related genes from resurrection plants may have huge prospects for rice yield improvement. Here, we review the comprehensive multidisciplinary analyses to unravel different components and mechanisms involved in drought-induced cell wall plasticity at vegetative and reproductive stages that could be targeted for improving rice yield under drought.


Assuntos
Parede Celular/química , Secas , Oryza/citologia , Oryza/genética , Proteínas de Plantas/genética , Parede Celular/genética , Parede Celular/ultraestrutura , Regulação da Expressão Gênica de Plantas , Genômica/métodos , Oryza/crescimento & desenvolvimento , Raízes de Plantas/citologia , Raízes de Plantas/fisiologia , Brotos de Planta/citologia , Brotos de Planta/fisiologia , Locos de Características Quantitativas
19.
Plant J ; 105(3): 736-753, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33155350

RESUMO

We aimed to understand the underlying mechanisms of development in the sporopollenin-containing part of the pollen wall, the exine, one of the most complex cell walls in plants. Our hypothesis is that distinct physical processes, phase separation and micellar self-assembly, underpinexine development by taking the molecular building blocks, determined and synthesised by the genome, through several phase transitions. To test this hypothesis, we traced each stage of microspore development in Calycanthus floridus with transmission electron microscopy and then generated in vitro experimental simulations corresponding to every developmental stage. The sequence of structures observed within the periplasmic space around developing microspores starts with spherical units, which are rearranged into columns to then form rod-like units (the young columellae) and, finally, white line centred endexine lamellae. Phase separation precedes each developmental stage. The set of experimental simulations, obtained as self-assembled micellar mesophases formed at the interface between lipid and water compartments, was the same: spherical micelles; columns of spherical micelles; cylindrical micelles; and laminate micelles, separated by gaps, resembling white-lined lamellae. Thus, patterns simulating structures observed at the main stages of exine development in C. floridus were obtained from in vitro experiments, and hence purely physicochemical processes can construct exine-like patterns. This highlights the important part played by physical processes that are not under direct genomic control and share influence on the emerging ultrastructure with the genome during exine development. These findings suggest that a new approach to ontogenetic studies, including a consideration of physical factors, is required for a better understanding of developmental processes.


Assuntos
Calycanthaceae/crescimento & desenvolvimento , Parede Celular/ultraestrutura , Pólen/citologia , Membrana Celular/ultraestrutura , Parede Celular/química , Flores/fisiologia , Microscopia Eletrônica de Transmissão , Células Vegetais , Pólen/crescimento & desenvolvimento
20.
Methods Mol Biol ; 2200: 349-369, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33175387

RESUMO

Atomic force microscopy (AFM) is an indentation technique used to reconstruct the topography of various materials and organisms. AFM can also measure the mechanical properties of the sample. In plants, AFM is applied to image cell wall structural details and measure the elastic properties in the outer cell walls. Here, I describe the use of high-resolution AFM to measure the elasticity of resin-embedded ultrathin sections of leaf epidermal cell walls. This approach allows to access the fine details within the wall matrix and eliminate the influence of the topography or the turgor on mechanical measurements. In this chapter, the sample preparation, AFM image acquisition, and processing of force curves are described. Altogether, these methods allow to measure the wall stiffness and compare different cell wall regions.


Assuntos
Arabidopsis/ultraestrutura , Parede Celular/ultraestrutura , Microscopia de Força Atômica , Epiderme Vegetal/ultraestrutura , Folhas de Planta/ultraestrutura
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