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Biao Ding - One of the best experts on this subject based on the ideXlab platform.
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Developmental Regulation of Intercellular Protein Trafficking through Plasmodesmata in Tobacco Leaf Epidermis
Plant physiology, 1998Co-Authors: Asuka Itaya, Young-min Woo, Chikara Masuta, Yiming Bao, Richard S. Nelson, Biao DingAbstract:Plasmodesmata mediate direct cell-to-cell communication in plants. One of their significant features is that primary Plasmodesmata formed at the time of cytokinesis often undergo structural modifications, by the de novo addition of cytoplasmic strands across cell walls, to become complex secondary Plasmodesmata during plant development. Whether such modifications allow Plasmodesmata to gain special transport functions has been an outstanding issue in plant biology. Here we present data showing that the cucumber mosaic virus 3a movement protein (MP):green fluorescent protein (GFP) fusion was not targeted to primary Plasmodesmata in the epidermis of young or mature leaves in transgenic tobacco (Nicotiana tabacum) plants constitutively expressing the 3a:GFP fusion gene. Furthermore, the cucumber mosaic virus 3a MP:GFP fusion protein produced in planta by biolistic bombardment of the 3a:GFP fusion gene did not traffic between cells interconnected by primary Plasmodesmata in the epidermis of a young leaf. In contrast, the 3a MP:GFP was targeted to complex secondary Plasmodesmata and trafficked from cell to cell when a leaf reached a certain developmental stage. These data provide the first experimental evidence, to our knowledge, that primary and complex secondary Plasmodesmata have different protein-trafficking functions and suggest that complex secondary Plasmodesmata may be formed to traffic specific macromolecules that are important for certain stages of leaf development.
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Mechanism of Plasmodesmata formation in characean algae in relation to evolution of intercellular communication in higher plants
Planta, 1994Co-Authors: Vincent R. Franceschi, Biao Ding, William J LucasAbstract:It is generally accepted that higher plants evolved from ancestral forms of the modern charophytes. For this reason, we chose the characean alga, Chara corallina Klein ex Willd., em. R.D.W. ( C. australis R. Br.), to determine whether this transition species produces Plasmodesmata in a manner analogous to higher plants. As with higher plants and unlike most green algae, Chara utilizes a phragmoplast for cell division; however, in contrast with the situation in both lower and higher vascular plants, the developing cell plate and newly formed cell wall were found to be completely free of Plasmodesmata. Only when the daughter cells had separated completely were Plasmodesmata formed across the division wall. Presumably, highly localized activity of wall-degrading (or loosening) enzymes inserted into the plasma membrane play a central role in this process. In general appearance characean Plasmodesmata are similar to those of higher plants with the notable exception that they lack an appressed endoplasmic reticulum. Further secondary modifications in plasmodesmal structure were found to occur as a function of cell development, giving rise to highly branched Plasmodesmata in mature cell walls. These findings are discussed in terms of the evolution of the mechanism for Plasmodesmata formation in algae and higher plants.
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secondary Plasmodesmata are specific sites of localization of the tobacco mosaic virus movement protein in transgenic tobacco plants
The Plant Cell, 1992Co-Authors: Biao Ding, James S Haudenshield, Richard J Hull, Shmuel Wolf, Roger Beachy, William J LucasAbstract:Expression of the tobacco mosaic virus 30-kD movement protein (TMV MP) gene in tobacco plants increases the Plasmodesmatal size exclusion limit (SEL) 10-fold between mesophyll cells in mature leaves. In the present study, we examined the structure of Plasmodesmata as a function of leaf development. In young leaves of 30-kD TMV MP transgenic (line 274) and vector control (line 306) plants, almost all Plasmodesmata were primary in nature. In both plant lines, secondary Plasmodesmata were formed, in a basipetal pattern, as the leaves underwent expansion growth. Ultrastructural and immunolabeling studies demonstrated that in line 274 the TMV MP accumulated predominantly in secondary Plasmodesmata of nonvascular tissues and was associated with a filamentous material. A developmental progression was detected in terms of the presence of TMV MP; all secondary Plasmodesmata in the tip of the fourth leaf contained TMV MP in association with the filamentous material. Dye-coupling experiments demonstrated that the TMV MP-induced increase in Plasmodesmatal SEL could be routinely detected in the tip of the fourth leaf, but was restricted to mesophyll and bundle sheath cells. These findings are discussed with respect to the structure and function of Plasmodesmata, particularly those aspects related to virus movement.
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Substructure of freeze-substituted Plasmodesmata
Protoplasma, 1992Co-Authors: Biao Ding, Robert Turgeon, M. V. ParthasarathyAbstract:The substructure of Plasmodesmata in freeze-substituted tissues of developing leaves of the tobacco plant (Nicotiana tabacum L. var. Maryland Mammoth) was studied by high resolution electron microscopy and computer image enhancement techniques. Both the desmotubule wall and the inner leaflet of the Plasmodesmatal plasma membrane are composed of regularly spaced electron-dense particles approximately 3 nm in diameter, presumably proteinaceous and embedded in lipid. The central rod of the desmotubule is also particulate. In Plasmodesmata with central cavities, spoke-like extensions are present between the desmotubule and the plasma membrane in the central cavity region. The space between the desmotubule and the plasma membrane appears to be the major pathway for intercellular transport through Plasmodesmata. This pathway may be tortuous and its dimensions could be regulated by interactions between desmotubule and plasma membrane particles.
Karl J Oparka - One of the best experts on this subject based on the ideXlab platform.
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Architecture and permeability of post-cytokinesis Plasmodesmata lacking cytoplasmic sleeves.
Nature plants, 2017Co-Authors: William J. Nicolas, Karl J Oparka, Magali S. Grison, Sylvain Trépout, Amélia Gaston, Mathieu Fouché, Fabrice P. Cordelières, Jens Tilsner, Lysiane Brocard, Emmanuelle M. BayerAbstract:High-resolution images and tomography show unprecedented 3D structures of Plasmodesmata. In cells just post-cytokinesis, Plasmodesmata do not have a visible cytoplasmic sleeve but still conduct cell-to-cell movement of micro- and macromolecules.
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The ER Within Plasmodesmata
Plant Cell Monographs, 2006Co-Authors: Kathryn M. Wright, Karl J OparkaAbstract:The endoplasmic reticulum (ER) is an essential component of Plasmodesmata, the membrane-lined poresthat interconnect plant cells. The desmotubule which traverses the centre of a plasmodesma is formedfrom, and continuous with, the cortical ER. Whilst the exact role of the ER is only now being characterised,it is recognised that the ER is intimately involved in the transfer of molecules to and through Plasmodesmata,providing a number of pathways for movement between cells as well as being implicated in the mechanismsthat control transport. It is believed that molecules may be transported by passive flow within the desmotubulelumen, by diffusion along the inner desmotubule membranes or by specific attachment to the cytoplasmic faceof the desmotubule followed by facilitated transport through the cytoplasmic sleeve. The ER is also involvedin the formation of Plasmodesmata either during cell division or when formed de novo across non-divisionwalls. This chapter focusses on the role of the ER in Plasmodesmatal formation and function.
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Plasmodesmata and the control of symplastic transport
Plant Cell & Environment, 2003Co-Authors: Alison G Roberts, Karl J OparkaAbstract:In 1879 Eduard Tangle discovered cytoplasmic connections between cells in the cotyledons of Strychnos nuxvomica , which he interpreted to be protoplasmic contacts. This led him to hypothesize that ‘the protoplasmic bodies . . . are united by thin strands passing through connecting ducts in the walls, which put the cells into connection with each other and so unite them to an entity of higher order’ (Carr 1976). This challenged the then current view that cells functioned as autonomous units. It was after much research in many other species and cell types that Strasburger, in 1901, named these structures Plasmodesmata (Carr 1976). During the division and differentiation of meristematic cells, Plasmodesmata are formed across each developing cell plate, allowing cytoplasmic and endomembrane continuity to occur between all daughter cells, and ultimately, between all cells in a developing tissue (Mezitt & Lucas 1996). Those Plasmodesmata that form during cell division are termed primary Plasmodesmata (Jones 1976). Those that form de novo across existing cell walls are called secondary Plasmodesmata (Ehlers & Kollmann 2001). The formation of secondary Plasmodesmata allows cells to increase their potential for molecular trafficking and allows connections to be created between cells that are not related cytokinetically. As cells expand and differentiate, their fate determines the extent to which their cytoplasmic connectivity to other cells is maintained (Mezitt & Lucas 1996). Some cell types, such as those of the leaf mesophyll, remain closely connected to their neighbours, and may even lay down additional Plasmodesmata to increase the continuity (Ding et al . 1992a). In other areas of the plant, for instance in vascular tissue, certain cells greatly reduce the number of Plasmodesmata in their adjoining walls (Gamalei 1989). In this way, the cytoplasmic continuity can be altered depending on the tissue type (Botha & Evert 1988; Brown et al . 1995). However, although reductions in the number of Plasmodesmata are common, only guard cells surrounding stomata (Erwee, Goodwin & van Bel 1985; Palevitz & Hepler 1985) and differentiating xylem elements (Lachaud & Maurousset 1996) lose all symplastic connections at maturity. In all other cells, some degree of intercellular connection is maintained. This plasmodesmal continuum that potentially exists throughout the whole plant is termed the symplast (Munch 1930). However, the symplast is not the open continuum that Munch originally hypothesized, but is divided into functional domains, each tightly regulated by different forms of Plasmodesmata (Erwee & Goodwin 1985; Ehlers & Kollmann 2001). Plasmodesmata are now thought of as fluid, dynamic structures that can be modified both structurally and functionally to cope with the requirements of specific cells and tissues.
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dynamic changes in the frequency and architecture of Plasmodesmata during the sink source transition in tobacco leaves
Protoplasma, 2001Co-Authors: I M Roberts, Petra C Boevink, Alison G Roberts, Norbert Sauer, C Reichel, Karl J OparkaAbstract:The sink-source transition in tobacco leaves was studied noninvasively using transgenic plants expressing the green-fluorescent protein (GFP) under control of theArabidopsis thaliana SUC2 promoter, and also by imaging transgenic plants that constitutively expressed a tobacco mosaic virus movement protein (MP) fused to GFP (MP-GFP). The sink-source transition was measured on intact leaves and progressed basipetally at rates of up to 600 μm/h. The transition was most rapid on the largest sink leaves. However, leaf size was a poor indicator of the current position of the sink-source transition. A quantitative study of Plasmodesmatal frequencies revealed the loss of enormous numbers of simple plasmodemata during the sink-source transition. In contrast, branched Plasmodesmata increased in frequency during the sink-source transition, particularly between periclinal cell walls of the spongy mesophyll. The progression of plasmodesmal branching, as mapped by the labelling of Plasmodesmata with MP-GFP fusion, occurred asynchronously in different cell layers, commencing in trichomes and appearing lastly in periclinal cell walls of the palisade layer. It appears that dividing cells retain simple Plasmodesmata for longer periods than nondividing cells. The rapid conversion of simple to branched Plasmodesmata is discussed in relation to the capacity for macromolecular trafficking in developing leaf tissues.
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simple but not branched Plasmodesmata allow the nonspecific trafficking of proteins in developing tobacco leaves
Cell, 1999Co-Authors: Karl J Oparka, I M Roberts, Petra C Boevink, Alison G Roberts, Norbert Sauer, Simon Santa Cruz, Guy Kotlizky, Katja S Pradel, Astrid Imlau, Bernard L. EpelAbstract:Abstract Leaves undergo a sink–source transition during which a physiological change occurs from carbon import to export. In sink leaves, biolistic bombardment of plasmids encoding GFP-fusion proteins demonstrated that proteins with an M r up to 50 kDa could move freely through Plasmodesmata. During the sink–source transition, the capacity to traffic proteins decreased substantially and was accompanied by a developmental switch from simple to branched forms of Plasmodesmata. Inoculation of sink leaves with a movement protein-defective virus showed that virally expressed GFP, but not viral RNA, was capable of trafficking between sink cells during infection. Contrary to dogma that Plasmodesmata have a size exclusion limit below 1 kDa, the data demonstrate that nonspecific "macromolecular trafficking" is a general feature of simple Plasmodesmata in sink leaves.
Patricia Zambryski - One of the best experts on this subject based on the ideXlab platform.
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Regulation of Plasmodesmal Transport and Modification of Plasmodesmata During Development and Following Infection by Viruses and Viral Proteins
Plant-Virus Interactions, 2016Co-Authors: Tessa M. Burch-smith, Patricia ZambryskiAbstract:Plant cells are encased in cellulose precluding direct contact. To enable intercellular communication, plants evolved cell wall-spanning channels called Plasmodesmata. Plasmodesmata are essential to facilitate transport of small molecules such as photosynthate, as well as critical signaling macromolecules such as transcription factors and RNAs. Plasmodesmata are indispensible for all stages of plant development, from embryogenesis, through vegetative and reproductive development. Plasmodesmata are not passive channels, but instead they are highly dynamic and change their apertures in response to intracellular signals such as reactive oxygen species, hormones, and chloroplast and mitochondrial homeostasis. To date the best-known mechanism for controlling the degree of Plasmodesmata transport is the reversible deposition of callose polysaccharides in the cell wall immediately surrounding Plasmodesmata channels. Plant viruses have evolved to counteract innate Plasmodesmata regulatory mechanisms and are well-known pirates of Plasmodesmata during infectious spread.
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identification of a developmental transition in Plasmodesmatal function during embryogenesis in arabidopsis thaliana
Development, 2002Co-Authors: Frederick D Hempel, Jennifer Pfluger, Patricia ZambryskiAbstract:Plasmodesmata provide routes for communication and nutrient transfer between plant cells by interconnecting the cytoplasm of adjacent cells. A simple fluorescent tracer loading assay was developed to monitor patterns of cell-to-cell transport via Plasmodesmata specifically during embryogenesis. A developmental transition in Plasmodesmatal size exclusion limit was found to occur at the torpedo stage of embryogenesis in Arabidopsis ; at this time, Plasmodesmata are down-regulated, allowing transport of small (approx. 0.5 kDa) but not large (approx. 10 kDa) tracers. This assay system was used to screen for embryo-defective mutants, designated increased size exclusion limit of Plasmodesmata ( ise ), that maintain dilated Plasmodesmata at the torpedo stage. The morphology of ise1 and ise2 mutants discussed here resembled that of the wild-type during embryo development, although the rate of their embryogenesis was slower. The ISE1 gene was mapped to position 13 cM on chromosome I using PCR-based biallelic markers. ise2 was found to be allelic to the previously characterized mutant emb25 which maps to position 100 cM on chromosome I. The results presented have implications for intercellular signaling pathways that regulate embryonic development, and furthermore represent the first attempt to screen directly for mutants of Arabidopsis with altered size exclusion limit of Plasmodesmata.
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Plasmodesmata: Gatekeepers for Cell-to-Cell Transport of Developmental Signals in Plants
Annual review of cell and developmental biology, 2000Co-Authors: Patricia Zambryski, Katrina M. CrawfordAbstract:▪ Abstract Cell walls separate individual plant cells. To enable essential intercellular communication, plants have evolved membrane-lined channels, termed Plasmodesmata, that interconnect the cytoplasm between neighboring cells. Historically, Plasmodesmata were viewed as facilitating traffic of low-molecular weight growth regulators and nutrients critical to growth. Evidence for macromolecular transport via Plasmodesmata was solely based on the exploitation of Plasmodesmata by plant viruses during infectious spread. Now Plasmodesmata are revealed to transport endogenous proteins, including transcription factors important for development. Two general types of proteins, non-targeted and Plasmodesmata-targeted, traffic Plasmodesmata channels. Size and subcellular location influence non-targeted protein transportability. Superimposed on cargo-specific parameters, Plasmodesmata themselves fluctuate in aperture between closed, open, and dilated. Furthermore, Plasmodesmata alter their transport capacity tempora...
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Tobacco mosaic virus movement protein associates with the cytoskeleton in tobacco cells.
The Plant cell, 1995Co-Authors: B G Mclean, J Zupan, Patricia ZambryskiAbstract:Tobacco mosaic virus movement protein P30 complexes with genomic viral RNA for transport through Plasmodesmata, the plant intercellular connections. Although most research with P30 focuses on its targeting to and gating of Plasmodesmata, the mechanisms of P30 intracellular movement to Plasmodesmata have not been defined. To examine P30 intracellular localization, we used tobacco protoplasts, which lack Plasmodesmata, for transfection with plasmids carrying P30 coding sequences under a constitutive promoter and for infection with tobacco mosaic virus particles. In both systems, P30 appears as filaments that colocalize primarily with microtubules. To a lesser extent, P30 filaments colocalize with actin filaments, and in vitro experiments suggested that P30 can bind directly to actin and tubulin. This association of P30 with cytoskeletal elements may play a critical role in intracellular transport of the P30-viral RNA complex through the cytoplasm to and possibly through Plasmodesmata.
William J Lucas - One of the best experts on this subject based on the ideXlab platform.
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Mechanism of Plasmodesmata formation in characean algae in relation to evolution of intercellular communication in higher plants
Planta, 1994Co-Authors: Vincent R. Franceschi, Biao Ding, William J LucasAbstract:It is generally accepted that higher plants evolved from ancestral forms of the modern charophytes. For this reason, we chose the characean alga, Chara corallina Klein ex Willd., em. R.D.W. ( C. australis R. Br.), to determine whether this transition species produces Plasmodesmata in a manner analogous to higher plants. As with higher plants and unlike most green algae, Chara utilizes a phragmoplast for cell division; however, in contrast with the situation in both lower and higher vascular plants, the developing cell plate and newly formed cell wall were found to be completely free of Plasmodesmata. Only when the daughter cells had separated completely were Plasmodesmata formed across the division wall. Presumably, highly localized activity of wall-degrading (or loosening) enzymes inserted into the plasma membrane play a central role in this process. In general appearance characean Plasmodesmata are similar to those of higher plants with the notable exception that they lack an appressed endoplasmic reticulum. Further secondary modifications in plasmodesmal structure were found to occur as a function of cell development, giving rise to highly branched Plasmodesmata in mature cell walls. These findings are discussed in terms of the evolution of the mechanism for Plasmodesmata formation in algae and higher plants.
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secondary Plasmodesmata are specific sites of localization of the tobacco mosaic virus movement protein in transgenic tobacco plants
The Plant Cell, 1992Co-Authors: Biao Ding, James S Haudenshield, Richard J Hull, Shmuel Wolf, Roger Beachy, William J LucasAbstract:Expression of the tobacco mosaic virus 30-kD movement protein (TMV MP) gene in tobacco plants increases the Plasmodesmatal size exclusion limit (SEL) 10-fold between mesophyll cells in mature leaves. In the present study, we examined the structure of Plasmodesmata as a function of leaf development. In young leaves of 30-kD TMV MP transgenic (line 274) and vector control (line 306) plants, almost all Plasmodesmata were primary in nature. In both plant lines, secondary Plasmodesmata were formed, in a basipetal pattern, as the leaves underwent expansion growth. Ultrastructural and immunolabeling studies demonstrated that in line 274 the TMV MP accumulated predominantly in secondary Plasmodesmata of nonvascular tissues and was associated with a filamentous material. A developmental progression was detected in terms of the presence of TMV MP; all secondary Plasmodesmata in the tip of the fourth leaf contained TMV MP in association with the filamentous material. Dye-coupling experiments demonstrated that the TMV MP-induced increase in Plasmodesmatal SEL could be routinely detected in the tip of the fourth leaf, but was restricted to mesophyll and bundle sheath cells. These findings are discussed with respect to the structure and function of Plasmodesmata, particularly those aspects related to virus movement.
Bernard L. Epel - One of the best experts on this subject based on the ideXlab platform.
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Plasmodesmata and plant cytoskeleton.
Trends in Plant Science, 2001Co-Authors: Rachid Aaziz, Sylvie Dinant, Bernard L. EpelAbstract:Abstract Plant cell-to-cell communication is achieved by membranous conduits called Plasmodesmata, which bridge the cytoplasm of neighboring cells. A growing body of immunolocalization data shows an association of the cytoskeleton machinery with Plasmodesmata. The role of the cytoskeleton in the Plasmodesmata-mediated transport has been well documented for virus movement. Because viruses are known to exploit existing host pathways and because the cytoskeleton is involved in intracellular trafficking, the cytoskeleton is thought to drive and target macromolecules to Plasmodesmata. It is this link between Plasmodesmata and the cytoskeleton that will be described here.
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simple but not branched Plasmodesmata allow the nonspecific trafficking of proteins in developing tobacco leaves
Cell, 1999Co-Authors: Karl J Oparka, I M Roberts, Petra C Boevink, Alison G Roberts, Norbert Sauer, Simon Santa Cruz, Guy Kotlizky, Katja S Pradel, Astrid Imlau, Bernard L. EpelAbstract:Abstract Leaves undergo a sink–source transition during which a physiological change occurs from carbon import to export. In sink leaves, biolistic bombardment of plasmids encoding GFP-fusion proteins demonstrated that proteins with an M r up to 50 kDa could move freely through Plasmodesmata. During the sink–source transition, the capacity to traffic proteins decreased substantially and was accompanied by a developmental switch from simple to branched forms of Plasmodesmata. Inoculation of sink leaves with a movement protein-defective virus showed that virally expressed GFP, but not viral RNA, was capable of trafficking between sink cells during infection. Contrary to dogma that Plasmodesmata have a size exclusion limit below 1 kDa, the data demonstrate that nonspecific "macromolecular trafficking" is a general feature of simple Plasmodesmata in sink leaves.
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ISOLATION AND CHARACTERIZATION OF Plasmodesmata
Methods in cell biology, 1995Co-Authors: Bernard L. Epel, Kuchuck B, Guy Kotlizky, Shurtz S, Erlanger M, Avital YahalomAbstract:Publisher Summary This chapter discusses the isolation and characterization of Plasmodesmata. Plasmodesmata are dynamic membrane specializations that traverse plant cell walls forming aqueous channels linking adjacent cells. The plasmodesma—like its animal counterpart, the gap junction—functions in the cytoplasmic movement of metabolites and ions. There is strong evidence that Plasmodesmata may function to provide a mechanism for intercellular signaling. In addition to their normal physiological function, Plasmodesmata can be altered and exploited by viruses as conduits for viral spread from cell to cell. There are also some indications that Plasmodesmata in companion cells may be specialized, allowing for the transport of proteins from the companion cells to sieve tube elements. The outer limit of a plasmodesma is formed by the plasmalemma, which is continuous from cell to cell. Within the interior of the plasmalemma tubular envelope runs a strand of modified endoplasmic reticulum that is apparently appressed as seen in static endoplasmic reticulum (ER) micrograph studies and has been termed by various workers as “desmotubule” or “appressed endoplasmic reticulum.”
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Plasmodesmata: composition, structure and trafficking.
Plant molecular biology, 1994Co-Authors: Bernard L. EpelAbstract:Plasmodesmata are highly specialized gatable trans-wall channels that interconnect contiguous cells and function in direct cytoplasm-to-cytoplasm intercellular transport. Computer-enhanced digital imaging analysis of electron micrographs of Plasmodesmata has provided new information on Plasmodesmatal fine structure. It is now becoming clear that Plasmodesmata are dynamic quasi-organelles whose conductivity can be regulated by environmental and developmental signals. New findings suggest that signalling mechanisms exist which allow the Plasmodesmatal pore to dilate to allow macromolecular transport. Plant viruses spread from cell to cell via Plasmodesmata. Two distinct movement mechanisms have been elucidated. One movement mechanism involves the movement of the complete virus particle along virus-induced tubular structures within a modified plasmodesma. Apparently two virus-coded movement proteins are involved. A second movement mechanism involves the movement of a non-virion form through existing Plasmodesmata. In this mechanism, the viral movement protein causes a rapid dilation of existing Plasmodesmata to facilitate protein and nucleic acid movement. Techniques for the isolation of Plasmodesmata have been developed and information on plasmodesma-associated proteins is now becoming available. New evidence is reviewed which suggests that Plasmodesmatal composition and regulation may differ in different cells and tissues.
