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Methods in Molecular Biology (Clifton,... 2022Plant plasmodesmata (PD) are complex intercellular channels consisting of a thin endoplasmic reticulum (ER) tubule enveloped by the plasma membrane (PM). PD were first...
Plant plasmodesmata (PD) are complex intercellular channels consisting of a thin endoplasmic reticulum (ER) tubule enveloped by the plasma membrane (PM). PD were first observed by electron microscopy about 50 years ago and, since, numerous studies in transmission and scanning electron microscopy have provided important information regarding their overall organization, revealing at the same time their diversity in terms of structure and morphology. However, and despite the fact that PD cell-cell communication is of critical importance for plant growth, development, cellular patterning, and response to biotic and abiotic stresses, linking their structural organization to their functional state has been proven difficult. This is in part due to their small size (20-50 nm in diameter) and the difficulty to resolve these structures in three dimensions at nanometer resolution to provide details of their internal organization.In this protocol, we provide in detail a complete process to produce high-resolution transmission electron tomograms of PD. We describe the preparation of the plant sample using high-pressure cryofixation and cryo-substitution. We also describe how to prepare filmed grids and how to cut and collect the sections using an ultramicrotome. We explain how to acquire a tilt series and how to reconstruct a tomogram from it using the IMOD software. We also give a few guidelines on segmentation of the reconstructed tomogram.
Topics: Electron Microscope Tomography; Microscopy, Electron, Scanning; Microtomy; Plant Cells; Plasmodesmata
PubMed: 35349132
DOI: 10.1007/978-1-0716-2132-5_3 -
Plants (Basel, Switzerland) Mar 2018Communication between cells is an essential process for developing and maintaining multicellular collaboration during plant development and physiological adaptation in...
Communication between cells is an essential process for developing and maintaining multicellular collaboration during plant development and physiological adaptation in response to environmental stimuli. The intercellular movement of proteins and RNAs in addition to the movement of small nutrients or signaling molecules such as sugars and phytohormones has emerged as a novel mechanism of cell-to-cell signaling in plants. As a strategy for efficient intercellular communication and long-distance molecule movement, plants have evolved plant-specific symplasmic communication networks via plasmodesmata (PDs) and the phloem.
PubMed: 29558398
DOI: 10.3390/plants7010023 -
Methods in Molecular Biology (Clifton,... 2017Plasmodesmata (PD) are plasma membrane lined pores that cross the plant cell wall and connect adjacent cells. Plasmodesmata are composed of elements of the endoplasmic...
Plasmodesmata (PD) are plasma membrane lined pores that cross the plant cell wall and connect adjacent cells. Plasmodesmata are composed of elements of the endoplasmic reticulum, plasma membrane, cytosol, and cell wall and thus, as multicomposite structures that are embedded in the cell wall, they are notoriously difficult to isolate from whole plant tissue. However, understanding PD structure, function, and regulation necessitates identification of their molecular components and therefore proteomic and lipidomic analyses of PD fractions are an essential strategy for plasmodesmal biology. Here we outline a simple two-step purification procedure that allows isolation of PD-derived membranes from Arabidopsis suspension cells. The method involves isolation of purified cell wall fragments containing intact PD which is followed by enzymatic degradation of the cell wall to release the PD. This membrane-rich fraction can be subjected to protein and lipid extraction for molecular characterization of PD components. The first step of this procedure involves the isolation of cell wall fragments containing intact PD, free from contamination from other cellular compartments. Purified PD membranes are then released from the cell wall matrix by enzymatic degradation. Isolated PD membranes provide a suitable starting material for the analysis of PD-associated proteins and lipids.
Topics: Arabidopsis; Arabidopsis Proteins; Biomarkers; Blotting, Western; Carrier Proteins; Cell Culture Techniques; Cell Fractionation; Cell Wall; Cellulase; Culture Media; Electrophoresis, Polyacrylamide Gel; Hydrolysis; Intracellular Membranes; Intracellular Signaling Peptides and Proteins; Membrane Glycoproteins; Plant Cells; Plasmodesmata
PubMed: 27730612
DOI: 10.1007/978-1-4939-6533-5_15 -
Molecular Plant Pathology Dec 2023The genus Potyvirus is considered as the largest among plant single-stranded (positive-sense) RNA viruses, causing considerable economic damage to vegetable and fruit... (Review)
Review
The genus Potyvirus is considered as the largest among plant single-stranded (positive-sense) RNA viruses, causing considerable economic damage to vegetable and fruit crops worldwide. Through the coordinated action of four viral proteins and a few identified host factors, potyviruses exploit the endomembrane system of infected cells for their replication and for their intra- and intercellular movement to and through plasmodesmata (PDs). Although a significant amount of data concerning potyvirus movement has been published, no synthetic review compiling and integrating all information relevant to our current understanding of potyvirus transport is available. In this review, we highlight the complexity of potyvirus movement pathways and present three potential nonexclusive mechanisms based on (1) the use of the host endomembrane system to produce membranous replication vesicles that are targeted to PDs and move from cell to cell, (2) the movement of extracellular viral vesicles in the apoplasm, and (3) the transport of virion particles or ribonucleoprotein complexes through PDs. We also present and discuss experimental data supporting these different models as well as the aspects that still remain mostly speculative.
Topics: Potyvirus; Viral Proteins; Plant Diseases; Nicotiana
PubMed: 37571979
DOI: 10.1111/mpp.13383 -
Journal of Plant Physiology Apr 2024Root growth and development need proper carbon partitioning between sources and sinks. Photosynthesis products are unloaded from the phloem and enter the root meristem... (Review)
Review
Root growth and development need proper carbon partitioning between sources and sinks. Photosynthesis products are unloaded from the phloem and enter the root meristem cell by cell. While sugar transporters play a major role in phloem loading, phloem unloading occurs via the plasmodesmata in growing root tips. The aperture and permeability of plasmodesmata strongly influence symplastic unloading. Recent research has dissected the symplastic path for phloem unloading and identified several genes that regulate phloem unloading in the root. Callose turnover and membrane lipid composition alter the shape of plasmodesmata, allowing fine-tuning to adapt phloem unloading to the environmental and developmental conditions. Unloaded sugars act both as an energy supply and as signals to coordinate root growth and development. Increased knowledge of how phloem unloading is regulated enhances our understanding of carbon allocation in plants. In the future, it may be possible to modulate carbon allocation between sources and sinks in a manner that would contribute to increased plant biomass and carbon fixation.
Topics: Phloem; Plants; Biological Transport; Meristem; Carbon
PubMed: 38428153
DOI: 10.1016/j.jplph.2024.154203 -
The Plant Genome Dec 2023As conserved regulatory agents, noncoding RNAs (ncRNAs) have an important impact on many aspects of plant life, including growth, development, and environmental... (Review)
Review
As conserved regulatory agents, noncoding RNAs (ncRNAs) have an important impact on many aspects of plant life, including growth, development, and environmental response. Noncoding RNAs can travel through not only plasmodesma and phloem but also intercellular barriers to regulate distinct processes. Increasing evidence shows that the intercellular trans-kingdom transmission of ncRNAs is able to modulate many important interactions between plants and other organisms, such as plant response to pathogen attack, the symbiosis between legume plants and rhizobia and the interactions with parasitic plants. In these interactions, plant ncRNAs are believed to be sorted into extracellular vesicles (EVs) or other nonvesicular vehicles to pass through cell barriers and trigger trans-kingdom RNA interference (RNAi) in recipient cells from different species. There is evidence that the features of extracellular RNAs and associated RNA-binding proteins (RBPs) play a role in defining the RNAs to retain in cell or secrete outside cells. Despite the few reports about RNA secretion pathway in plants, the export of extracellular ncRNAs is orchestrated by a series of pathways in plants. The identification and functional analysis of mobile small RNAs (sRNAs) are attracting increasing attention in recent years. In this review, we discuss recent advances in our understanding of the function, sorting, transport, and regulation of plant extracellular ncRNAs.
Topics: Gene-Environment Interaction; RNA Interference; RNA, Untranslated; RNA, Plant; Plants
PubMed: 36444889
DOI: 10.1002/tpg2.20289 -
Methods in Molecular Biology (Clifton,... 2022Plasmodesmata are plant intercellular channels that mediate the transport of small and large molecules including RNAs and transcription factors (TFs) that regulate plant... (Review)
Review
Plasmodesmata are plant intercellular channels that mediate the transport of small and large molecules including RNAs and transcription factors (TFs) that regulate plant development. In this review, we present current research on plasmodesmata form and function and discuss the main regulatory pathways. We show the progress made in the development of approaches and tools to dissect the plasmodesmata proteome in diverse plant species and discuss future perspectives and challenges in this field of research.
Topics: Cell Communication; Plant Development; Plant Proteins; Plasmodesmata; Signal Transduction
PubMed: 35349130
DOI: 10.1007/978-1-0716-2132-5_1 -
Journal of Experimental Botany Dec 2017Plasmodesmata (PD) are a hallmark of the plant kingdom and a cornerstone of plant biology and physiology, forming the conduits for the cell-to-cell transfer of proteins,... (Review)
Review
Plasmodesmata (PD) are a hallmark of the plant kingdom and a cornerstone of plant biology and physiology, forming the conduits for the cell-to-cell transfer of proteins, RNA and various metabolites, including hormones. They connect the cytosols and endomembranes of cells, which allows enhanced cell-to-cell communication and synchronization. Because of their unique position as intercellular gateways, they are at the frontline of plant defence and signalling and constitute the battleground for virus replication and spreading. The membranous organization of PD is remarkable, where a tightly furled strand of endoplasmic reticulum comes into close apposition with the plasma membrane, the two connected by spoke-like elements. The role of these structural features is, to date, still not completely understood. Recent data on PD seem to point in an unexpected direction, establishing a close parallel between PD and membrane contact sites and defining plasmodesmal membranes as microdomains. However, the implications of this new viewpoint are not fully understood. Aided by available phylogenetic data, this review attempts to reassess the function of the different elements comprising the PD and the relevance of membrane lipid composition and biophysics in defining specialized microdomains of PD, critical for their function.
Topics: Biological Transport; Biophysical Phenomena; Cell Membrane; Cytosol; Endoplasmic Reticulum; Membrane Lipids; Plants; Plasmodesmata; Signal Transduction
PubMed: 28992136
DOI: 10.1093/jxb/erx225 -
Plant Science : An International... Mar 2021Cell-to-cell communication is crucial in coordinating diverse biological processes in multicellular organisms. In plants, communication between adjacent cells occurs via... (Review)
Review
Cell-to-cell communication is crucial in coordinating diverse biological processes in multicellular organisms. In plants, communication between adjacent cells occurs via nanotubular passages called plasmodesmata (PD). The PD passage is composed of an appressed endoplasmic reticulum (ER) internally, and plasma membrane (PM) externally, that traverses the cell wall, and associates with the actin-cytoskeleton. The coordination of the ER, PM and cytoskeleton plays a potential role in maintaining the architecture and conductivity of PD. Many data suggest that PD-associated proteins can serve as tethers that connect these structures in a functional PD, to regulate cell-to-cell communication. In this review, we summarize the organization and regulation of PD activity via tethering proteins, and discuss the importance of PD-mediated cell-to-cell communication in plant development and defense against environmental stress.
Topics: Actins; Cell Membrane; Cell Wall; Endoplasmic Reticulum; Membrane Proteins; Plant Proteins; Plants; Plasmodesmata
PubMed: 33568299
DOI: 10.1016/j.plantsci.2020.110800 -
Methods in Cell Biology 2020Plasmodesmata are membrane-lined cytoplasmic passageways that facilitate the movement of nutrients and various types of molecules between cells in the plant. They are...
Plasmodesmata are membrane-lined cytoplasmic passageways that facilitate the movement of nutrients and various types of molecules between cells in the plant. They are highly dynamic channels, opening or closing in response to physiological and developmental stimuli or environmental challenges such as biotic and abiotic stresses. Accumulating evidence supports the idea that such dynamic controls occur through integrative cellular mechanisms. Currently, a few fluorescence-based methods are available that allow monitoring changes in molecular movement through plasmodesmata. In this chapter, following a brief introduction to those methods, we provide a detailed step-by-step protocol for the Drop-ANd-See (DANS) assay, which is advantageous when it is desirable to measure plasmodesmal permeability non-invasively, in situ and in real-time. We discuss the experimental conditions one should consider to produce reliable and reproducible DANS results along with troubleshooting ideas.
Topics: Arabidopsis; Biological Assay; Biological Transport; Coloring Agents; Cytological Techniques; Fluoresceins; Image Processing, Computer-Assisted; Plant Development; Plasmodesmata; Reproducibility of Results
PubMed: 32896335
DOI: 10.1016/bs.mcb.2020.04.008