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Schreiber JM, Limpens E, de Keijzer J. Distributing Plant Developmental Regulatory Proteins via Plasmodesmata. PLANTS (BASEL, SWITZERLAND) 2024; 13:684. [PMID: 38475529 DOI: 10.3390/plants13050684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
During plant development, mobile proteins, including transcription factors, abundantly serve as messengers between cells to activate transcriptional signaling cascades in distal tissues. These proteins travel from cell to cell via nanoscopic tunnels in the cell wall known as plasmodesmata. Cellular control over this intercellular movement can occur at two likely interdependent levels. It involves regulation at the level of plasmodesmata density and structure as well as at the level of the cargo proteins that traverse these tunnels. In this review, we cover the dynamics of plasmodesmata formation and structure in a developmental context together with recent insights into the mechanisms that may control these aspects. Furthermore, we explore the processes involved in cargo-specific mechanisms that control the transport of proteins via plasmodesmata. Instead of a one-fits-all mechanism, a pluriform repertoire of mechanisms is encountered that controls the intercellular transport of proteins via plasmodesmata to control plant development.
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Affiliation(s)
- Joyce M Schreiber
- Laboratory of Cell and Developmental Biology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Erik Limpens
- Laboratory of Molecular Biology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Jeroen de Keijzer
- Laboratory of Cell and Developmental Biology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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2
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Reagan BC, Dunlap JR, Burch-Smith TM. Focused Ion Beam-Scanning Electron Microscopy for Investigating Plasmodesmal Densities. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2457:109-123. [PMID: 35349135 DOI: 10.1007/978-1-0716-2132-5_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Plasmodesmata (PD) facilitate the exchange of nutrients and signaling molecules between neighboring plant cells, and they are therefore essential for proper growth and development. PD have been studied extensively in efforts to elucidate the ultrastructure of individual PD nanopores and the distribution of PD in a variety of cell walls. These studies often involved the use of serial ultrathin sections and manual quantification of PD by transmission electron microscopy (TEM). In recent years, a variety of techniques that offer more amenable approaches for quantifying PD distribution have been reported. Here, we describe the quantification of PD densities using the serial scanning electron microscopy technique called focused ion beam-scanning electron microscopy (FIB-SEM). For this, resin-embedded samples prepared by standard TEM methods undergo successive rounds of imaging by SEM interspersed with milling of the sample surface by a focused beam of gallium ions to reveal a new surface. In this way, the details of the sample are sequentially revealed and imaged. Over the course of a few hours, repetitive milling and imaging facilitates the automated collection of nanometer-resolution data of several μm of sample depth. FIB-SEM can be targeted to interrogate specific cell walls and cell wall junctions, and the subsequent three-dimensional renderings of the data can be used to visualize the ultrastructural details of the sample. PD densities can then be rapidly quantified by calculating the number of PD per μm2 of cell wall observed in the renderings.
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Affiliation(s)
- Brandon C Reagan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA.,Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - John R Dunlap
- The Joint Institute for Advanced Materials, University of Tennessee, Knoxville, TN, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA. .,Donald Danforth Plant Science Center, Saint Louis, MO, USA.
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3
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Fernandez JC, Burch-Smith TM. Investigating Plasmodesmata Function in Arabidopsis Thaliana Using a Low-Pressure Bombardment System and GFP Movement Assay. Methods Mol Biol 2022; 2457:273-283. [PMID: 35349147 DOI: 10.1007/978-1-0716-2132-5_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Plasmodesmata are nanopores in the plant cell wall that allow direct cell-to-cell communication. They are key for plant growth, development, and defense. However, studying these pores is challenging due to their small size, with diameters of 30-50 nm and lengths that match cell wall thickness. One particular challenge is measuring how much cell-to-cell trafficking is facilitated by the plasmodesmata in a tissue or between particular cells. Here, we present an approach for studying plasmodesmata-mediated trafficking in the model plant Arabidopsis thaliana by using an easy-to-build and affordable low-pressure particle bombardment apparatus. Using low-pressure particle bombardment at around 60 psi, we are able to transform individual cells in the leaf epidermis and study by confocal fluorescence microscopy the subsequent cell-to-cell trafficking of the diffusible molecule green fluorescent protein (GFP). The technique and equipment could be used by any plant biologist to measure intercellular trafficking through plasmodesmata under varying growth conditions including exposure to different stresses, light conditions, chemical treatments, or in various mutant backgrounds.
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Affiliation(s)
- Jessica C Fernandez
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
- Department of Botany, University of Wisconsin, Madison, WI, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA.
- Donald Danforth Plant Science Center, Saint Louis, MO, USA.
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4
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Sankoh AF, Burch-Smith TM. Approaches for investigating plasmodesmata and effective communication. CURRENT OPINION IN PLANT BIOLOGY 2021; 64:102143. [PMID: 34826658 DOI: 10.1016/j.pbi.2021.102143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Plasmodesmata (PD) are integral plant cell wall components that provide routes for intercellular communication, signaling, and resource sharing. They are therefore essential for plant growth and survival. Much effort has been put forth to understand how PD are generated and their structure is refined for function and to determine how they regulate intercellular trafficking. This review provides an overview of some of the approaches that have been used to study PD structure and function, highlighting those that may be more widely adopted to address questions of PD cell biology and function. Extending our focus on the importance of communication, we address how effective communication strategies can increase diversity and accessibility in the research laboratory, focusing on challenges faced by our deaf/hard-of-hearing colleagues, and highlight successful approaches to including them in the research laboratory.
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Affiliation(s)
- Amie F Sankoh
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States.
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5
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Abstract
Auxin is an endogenous small molecule with an incredibly large impact on growth and development in plants. Movement of auxin between cells, due to its negative charge at most physiological pHs, strongly relies on families of active transporters. These proteins import auxin from the extracellular space or export it into the same. Mutations in these components have profound impacts on biological processes. Another transport route available to auxin, once the substance is inside the cell, are plasmodesmata connections. These small channels connect the cytoplasms of neighbouring plant cells and enable flow between them. Interestingly, the biological significance of this latter mode of transport is only recently starting to emerge with examples from roots, hypocotyls and leaves. The existence of two transport systems provides opportunities for reciprocal cross-regulation. Indeed, auxin levels influence proteins controlling plasmodesmata permeability, while cell-cell communication affects auxin biosynthesis and transport. In an evolutionary context, transporter driven cell-cell auxin movement and plasmodesmata seem to have evolved around the same time in the green lineage. This highlights a co-existence from early on and a likely functional specificity of the systems. Exploring more situations where auxin movement via plasmodesmata has relevance for plant growth and development, and clarifying the regulation of such transport, will be key aspects in coming years.This article has an associated Future Leader to Watch interview with the author of the paper.
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Affiliation(s)
- Andrea Paterlini
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1 LR, UK
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6
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Intercellular trafficking via plasmodesmata: molecular layers of complexity. Cell Mol Life Sci 2020; 78:799-816. [PMID: 32920696 PMCID: PMC7897608 DOI: 10.1007/s00018-020-03622-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/28/2020] [Accepted: 08/13/2020] [Indexed: 12/12/2022]
Abstract
Plasmodesmata are intercellular pores connecting together most plant cells. These structures consist of a central constricted form of the endoplasmic reticulum, encircled by some cytoplasmic space, in turn delimited by the plasma membrane, itself ultimately surrounded by the cell wall. The presence and structure of plasmodesmata create multiple routes for intercellular trafficking of a large spectrum of molecules (encompassing RNAs, proteins, hormones and metabolites) and also enable local signalling events. Movement across plasmodesmata is finely controlled in order to balance processes requiring communication with those necessitating symplastic isolation. Here, we describe the identities and roles of the molecular components (specific sets of lipids, proteins and wall polysaccharides) that shape and define plasmodesmata structural and functional domains. We highlight the extensive and dynamic interactions that exist between the plasma/endoplasmic reticulum membranes, cytoplasm and cell wall domains, binding them together to effectively define plasmodesmata shapes and purposes.
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7
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Hernández-Hernández V, Benítez M, Boudaoud A. Interplay between turgor pressure and plasmodesmata during plant development. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:768-777. [PMID: 31563945 DOI: 10.1093/jxb/erz434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 09/09/2019] [Indexed: 06/10/2023]
Abstract
Plasmodesmata traverse cell walls, generating connections between neighboring cells. They allow intercellular movement of molecules such as transcription factors, hormones, and sugars, and thus create a symplasmic continuity within a tissue. One important factor that determines plasmodesmal permeability is their aperture, which is regulated during developmental and physiological processes. Regulation of aperture has been shown to affect developmental events such as vascular differentiation in the root, initiation of lateral roots, or transition to flowering. Extensive research has unraveled molecular factors involved in the regulation of plasmodesmal permeability. Nevertheless, many plant developmental processes appear to involve feedbacks mediated by mechanical forces, raising the question of whether mechanical forces and plasmodesmal permeability affect each other. Here, we review experimental data on how one of these forces, turgor pressure, and plasmodesmal permeability may mutually influence each other during plant development, and we discuss the questions raised by these data. Addressing such questions will improve our knowledge of how cellular patterns emerge during development, shedding light on the evolution of complex multicellular plants.
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Affiliation(s)
- Valeria Hernández-Hernández
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France
| | - Mariana Benítez
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología & Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Arezki Boudaoud
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France
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8
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Deinum EE, Mulder BM, Benitez-Alfonso Y. From plasmodesma geometry to effective symplasmic permeability through biophysical modelling. eLife 2019; 8:49000. [PMID: 31755863 PMCID: PMC6994222 DOI: 10.7554/elife.49000] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 11/16/2019] [Indexed: 12/12/2022] Open
Abstract
Regulation of molecular transport via intercellular channels called plasmodesmata (PDs) is important for both coordinating developmental and environmental responses among neighbouring cells, and isolating (groups of) cells to execute distinct programs. Cell-to-cell mobility of fluorescent molecules and PD dimensions (measured from electron micrographs) are both used as methods to predict PD transport capacity (i.e., effective symplasmic permeability), but often yield very different values. Here, we build a theoretical bridge between both experimental approaches by calculating the effective symplasmic permeability from a geometrical description of individual PDs and considering the flow towards them. We find that a dilated central region has the strongest impact in thick cell walls and that clustering of PDs into pit fields strongly reduces predicted permeabilities. Moreover, our open source multi-level model allows to predict PD dimensions matching measured permeabilities and add a functional interpretation to structural differences observed between PDs in different cell walls.
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Affiliation(s)
- Eva E Deinum
- Mathematical and statistical methods (Biometris), Wageningen University, Wageningen, Netherlands
| | - Bela M Mulder
- Living Matter Department, Institute AMOLF, Amsterdam, Netherlands.,Laboratory of Cell Biology, Wageningen University, Wageningen, Netherlands
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9
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Day TA, Bliss MS, Placek SK, Tomes AR, Guénon R. Thermal abiotic emission of
CO
2
and
CH
4
from leaf litter and its significance in a photodegradation assessment. Ecosphere 2019. [DOI: 10.1002/ecs2.2745] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Thomas A. Day
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA
| | - Michael S. Bliss
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA
| | - Sarah K. Placek
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA
| | - Alexander R. Tomes
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA
| | - René Guénon
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA
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10
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Ganusova EE, Burch-Smith TM. Review: Plant-pathogen interactions through the plasmodesma prism. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 279:70-80. [PMID: 30709495 DOI: 10.1016/j.plantsci.2018.05.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/18/2018] [Accepted: 05/23/2018] [Indexed: 06/09/2023]
Abstract
Plasmodesmata (PD) allow membrane and cytoplasmic continuity between plant cells, and they are essential for intercellular communication and signaling in addition to metabolite partitioning. Plant pathogens have evolved a variety of mechanisms to subvert PD to facilitate their infection of plant hosts. PD are implicated not only in local spread around infection sites but also in the systemic spread of pathogens and pathogen-derived molecules. In turn, plants have developed strategies to limit pathogen spread via PD, and there is increasing evidence that PD may also be active players in plant defense responses. The last few years have seen important advances in understanding the roles of PD in plant-pathogen infection. Nonetheless, several critical areas remain to be addressed. Here we highlight some of these, focusing on the need to consider the effects of pathogen-PD interaction on the trafficking of endogenous molecules, and the involvement of chloroplasts in regulating PD during pathogen defense. By their very nature, PD are recalcitrant to most currently used investigative techniques, therefore answering these questions will require creative imaging and novel quantification approaches.
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Affiliation(s)
- Elena E Ganusova
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, United States.
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11
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Reagan BC, Ganusova EE, Fernandez JC, McCray TN, Burch-Smith TM. RNA on the move: The plasmodesmata perspective. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 275:1-10. [PMID: 30107876 DOI: 10.1016/j.plantsci.2018.07.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/25/2018] [Accepted: 07/04/2018] [Indexed: 05/11/2023]
Abstract
It is now widely accepted that plant RNAs can have effects at sites far away from their sites of synthesis. Cellular mRNA transcripts, endogenous small RNAs and defense-related small RNAs all move from cell to cell via plasmodesmata (PD), and may even move long distances in the phloem. Despite their small size, PD have complicated substructures, and the area of the pore available for RNA trafficking can be remarkably small. The intent of this review is to bring into focus the role of PD in cell-to-cell and long distance communication in plants. We consider how cellular RNAs could move through the cell to the PD and thence through PD. The protein composition of PD and the possible roles of PD proteins in RNA trafficking are also discussed. Recent evidence for RNA metabolism in organelles acting as a factor in controlling PD flux is also presented, highlighting new aspects of plant intra- and intercellular communication. It is clear that while the phenomenon of RNA mobility is common and essential, many questions remain, and these have been highlighted throughout this review.
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Affiliation(s)
- Brandon C Reagan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Elena E Ganusova
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Jessica C Fernandez
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tyra N McCray
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States; School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, United States.
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12
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O’Lexy R, Kasai K, Clark N, Fujiwara T, Sozzani R, Gallagher KL. Exposure to heavy metal stress triggers changes in plasmodesmatal permeability via deposition and breakdown of callose. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3715-3728. [PMID: 29901781 PMCID: PMC6022669 DOI: 10.1093/jxb/ery171] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 05/15/2018] [Indexed: 05/19/2023]
Abstract
Both plants and animals must contend with changes in their environment. The ability to respond appropriately to these changes often underlies the ability of the individual to survive. In plants, an early response to environmental stress is an alteration in plasmodesmatal permeability with accompanying changes in cell to cell signaling. However, the ways in which plasmodesmata are modified, the molecular players involved in this regulation, and the biological significance of these responses are not well understood. Here, we examine the effects of nutrient scarcity and excess on plasmodesmata-mediated transport in the Arabidopsis thaliana root and identify two CALLOSE SYNTHASES and two β-1,3-GLUCANASES as key regulators of these processes. Our results suggest that modification of plasmodesmata-mediated signaling underlies the ability of the plant to maintain root growth and properly partition nutrients when grown under conditions of excess nutrients.
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Affiliation(s)
- Ruthsabel O’Lexy
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Koji Kasai
- Department of Agriculture and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Natalie Clark
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA
- Biomathematics Graduate Program, North Carolina State University, Raleigh, NC, USA
| | - Toru Fujiwara
- Department of Agriculture and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA
- Biomathematics Graduate Program, North Carolina State University, Raleigh, NC, USA
| | - Kimberly L Gallagher
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Correspondence:
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13
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Park MR, Seo JK, Kim KH. Viral and nonviral elements in potexvirus replication and movement and in antiviral responses. Adv Virus Res 2013; 87:75-112. [PMID: 23809921 DOI: 10.1016/b978-0-12-407698-3.00003-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In Potato virus X, a member of the genus Potexvirus, special sequences and structures at the 5' and 3' ends of the nontranslated region function as cis-acting elements for viral replication. These elements greatly affect interactions between viral RNAs and those between viral RNAs and host factors. The potexvirus genome encodes five open-reading frames. Viral replicase, which is required for the synthesis of viral RNA, binds viral RNA elements and host factors to form a viral replication complex at the host cellular membrane. The coat protein (CP) and three viral movement proteins (TGB1, TGB2, and TGB3) have critical roles in mediating cell-to-cell viral movement through plasmodesmata by virion formation or by nonvirion ribonucleoprotein (RNP) complex formation with viral movement proteins (TGBs). The RNP complex, like TGB1-CP-viral RNA, is associated with viral replicase and used for immediate reinitiation of viral replication in newly invaded cells. Higher plants have defense mechanisms against potexviruses such as Rx-mediated resistance and RNA silencing. The CP acts as an avirulence effector for plant defense mechanisms, while TGB1 functions as a viral suppressor of RNA silencing, which is the mechanism of innate immune resistance. Here, we describe recent findings concerning the involvement of viral and host factors in potexvirus replication and in antiviral responses to potexvirus infection.
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Affiliation(s)
- Mi-Ri Park
- Department of Agricultural Biotechnology, Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
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14
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Derendorp L, Wishkerman A, Keppler F, McRoberts C, Holzinger R, Röckmann T. Methyl chloride emissions from halophyte leaf litter: dependence on temperature and chloride content. CHEMOSPHERE 2012; 87:483-489. [PMID: 22225707 DOI: 10.1016/j.chemosphere.2011.12.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 05/31/2023]
Abstract
Methyl chloride (CH(3)Cl) is the most abundant natural chlorine containing compound in the atmosphere, and responsible for a significant fraction of stratospheric ozone destruction. Understanding the global CH(3)Cl budget is therefore of great importance. However, the strength of the individual sources and sinks is still uncertain. Leaf litter is a potentially important source of methyl chloride, but factors controlling the emissions are unclear. This study investigated CH(3)Cl emissions from leaf litter of twelve halophyte species. The emissions were not due to biological activity, and emission rates varied between halophyte species up to two orders of magnitude. For all species, the CH(3)Cl emission rates increased with temperature following the Arrhenius relation. Activation energies were similar for all investigated plant species, indicating that even though emissions vary largely between plant species, their response to changing temperatures is similar. The chloride and methoxyl group contents of the leaf litter samples were determined, but those parameters were not significantly correlated to the CH(3)Cl emission rate.
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Affiliation(s)
- Leonie Derendorp
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Princetonplein 5, 3584ED Utrecht, The Netherlands.
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15
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Betti C, Lico C, Maffi D, D'Angeli S, Altamura MM, Benvenuto E, Faoro F, Baschieri S. Potato virus X movement in Nicotiana benthamiana: new details revealed by chimeric coat protein variants. MOLECULAR PLANT PATHOLOGY 2012; 13:198-203. [PMID: 21851552 PMCID: PMC6638808 DOI: 10.1111/j.1364-3703.2011.00739.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Potato virus X coat protein is necessary for both cell-to-cell and phloem transfer, but it has not been clarified definitively whether it is needed in both movement phases solely as a component of the assembled particles or also of differently structured ribonucleoprotein complexes. To clarify this issue, we studied the infection progression of a mutant carrying an N-terminal deletion of the coat protein, which was used to construct chimeric virus particles displaying peptides selectively affecting phloem transfer or cell-to-cell movement. Nicotiana benthamiana plants inoculated with expression vectors encoding the wild-type, mutant and chimeric viral genomes were examined by microscopy techniques. These experiments showed that coat protein-peptide fusions promoting cell-to-cell transfer only were not competent for virion assembly, whereas long-distance movement was possible only for coat proteins compatible with virus particle formation. Moreover, the ability of the assembled PVX to enter and persist into developing xylem elements was revealed here for the first time.
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Affiliation(s)
- Camilla Betti
- Unità Tecnica Biologia delle Radiazioni e Salute dell'Uomo, Laboratorio di Biotecnologie, ENEA CR Casaccia, Via Anguillarese 301, 00123, Rome, Italy
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16
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Tilsner J, Amari K, Torrance L. Plasmodesmata viewed as specialised membrane adhesion sites. PROTOPLASMA 2011; 248:39-60. [PMID: 20938697 DOI: 10.1007/s00709-010-0217-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Accepted: 09/27/2010] [Indexed: 05/20/2023]
Abstract
A significant amount of work has been expended to identify the elusive components of plasmodesmata (PD) to help understand their structure, as well as how proteins are targeted to them. This review focuses on the role that lipid membranes may play in defining PD both structurally and as subcellular targeting addresses. Parallels are drawn to findings in other areas of research which focus on the lateral segregation of membrane domains and the generation of three-dimensional organellar shapes from flat lipid bilayers. We conclude that consideration of the protein-lipid interactions in cell biological studies of PD components and PD-targeted proteins may yield new insights into some of the many open questions regarding these unique structures.
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Affiliation(s)
- Jens Tilsner
- Institute of Molecular Plant Sciences, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3JH, UK.
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17
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Verchot-Lubicz J, Torrance L, Solovyev AG, Morozov SY, Jackson AO, Gilmer D. Varied movement strategies employed by triple gene block-encoding viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1231-47. [PMID: 20831404 DOI: 10.1094/mpmi-04-10-0086] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Several RNA virus genera belonging to the Virgaviridae and Flexiviridae families encode proteins organized in a triple gene block (TGB) that facilitate cell-to-cell and long-distance movement. The TGB proteins have been traditionally classified as hordei-like or potex-like based on phylogenetic comparisons and differences in movement mechanisms of the Hordeivirus and Potexvirus spp. However, accumulating data from other model viruses suggests that a revised framework is needed to accommodate the profound differences in protein interactions occurring during infection and ancillary capsid protein requirements for movement. The goal of this article is to highlight common features of the TGB proteins and salient differences in movement properties exhibited by individual viruses encoding these proteins. We discuss common and divergent aspects of the TGB transport machinery, describe putative nucleoprotein movement complexes, highlight recent data on TGB protein interactions and topological properties, and review membrane associations occurring during subcellular targeting and cell-to-cell movement. We conclude that the existing models cannot be used to explain all TGB viruses, and we propose provisional Potexvirus, Hordeivirus, and Pomovirus models. We also suggest areas that might profit from future research on viruses harboring this intriguing arrangement of movement proteins.
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Affiliation(s)
- Jeanmarie Verchot-Lubicz
- Oklahoma State University, Department of Entomology and Plant Pathology, Stillwater, OK 74078, USA.
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Simpson C, Thomas C, Findlay K, Bayer E, Maule AJ. An Arabidopsis GPI-anchor plasmodesmal neck protein with callose binding activity and potential to regulate cell-to-cell trafficking. THE PLANT CELL 2009; 21:581-94. [PMID: 19223515 PMCID: PMC2660613 DOI: 10.1105/tpc.108.060145] [Citation(s) in RCA: 215] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 01/05/2009] [Accepted: 01/26/2009] [Indexed: 05/18/2023]
Abstract
Plasmodesmata (Pds) traverse the cell wall to establish a symplastic continuum through most of the plant. Rapid and reversible deposition of callose in the cell wall surrounding the Pd apertures is proposed to provide a regulatory process through physical constriction of the symplastic channel. We identified members within a larger family of X8 domain-containing proteins that targeted to Pds. This subgroup of proteins contains signal sequences for a glycosylphosphatidylinositol linkage to the extracellular face of the plasma membrane. We focused our attention on three closely related members of this family, two of which specifically bind to 1,3-beta-glucans (callose) in vitro. We named this family of proteins Pd callose binding proteins (PDCBs). Yellow fluorescent protein-PDCB1 was found to localize to the neck region of Pds with potential to provide a structural anchor between the plasma membrane component of Pds and the cell wall. PDCB1, PDCB2, and PDCB3 had overlapping and widespread patterns of expression, but neither single nor combined insertional mutants for PDCB2 and PDCB3 showed any visible phenotype. However, increased expression of PDCB1 led to an increase in callose accumulation and a reduction of green fluorescent protein (GFP) movement in a GFP diffusion assay, identifying a potential association between PDCB-mediated callose deposition and plant cell-to-cell communication.
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Affiliation(s)
- Clare Simpson
- John Ines Centre, Norwich Research Park, Colney, Norwich, Norfolk NR4 7UH, United Kingdom
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Dashevskaya S, Kopito RB, Friedman R, Elbaum M, Epel BL. Diffusion of anionic and neutral GFP derivatives through plasmodesmata in epidermal cells of Nicotiana benthamiana. PROTOPLASMA 2008; 234:13-23. [PMID: 18797983 DOI: 10.1007/s00709-008-0014-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 07/24/2008] [Indexed: 05/08/2023]
Abstract
Plasmodesmata (Pd) are trans-wall membrane channels that permit cell-to-cell transport of metabolites and other small molecules, proteins, RNAs, and signaling molecules. The transport of cytoplasmic soluble macromolecules is a function of the electrochemical gradient between adjacent cells, the number of Pd per interface between adjacent cells, Stokes radius (R(S)), area of the cytoplasmic annulus, and channel length. The size of the largest molecule that can pass through Pd defines the Pd size exclusion limit. However, since the shape and size of a molecule determines its capacity to diffuse through pores or tubes, R(S) is a better measure. Relatively small changes in R(S) can cause large differences in the mobility of molecular probes, particularly if the pore size is close to that of the probe. In addition, as the dimensions of a macromolecule approach that of the channel, membrane charge effects may become important. We employed quantitative tools and molecular modeling to measure the apparent coefficient of conductivity of Pd, C(Pd), for the non-targeted transport of macromolecules. This method allowed us to examine the influence of protein charge and R(S) on C(Pd) in Nicotiana benthamiana. The C(Pd) of modified green fluorescent proteins (GFPs) of different sizes but with the same charge as native GFP and of a more negatively charged derivative were determined. We found that the C(Pd) of cytoplasmic soluble GFP and cytoplasmic forms of modified GFP were the most strongly correlated with R(S) and that the apparent aberrant increase in C(Pd) of a negatively charged GFP derivative was, at least in part, the result of the charge effect on R(S).
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Maule AJ. Plasmodesmata: structure, function and biogenesis. CURRENT OPINION IN PLANT BIOLOGY 2008; 11:680-6. [PMID: 18824402 DOI: 10.1016/j.pbi.2008.08.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 08/01/2008] [Accepted: 08/12/2008] [Indexed: 05/07/2023]
Abstract
Plasmodesmata remain one of the outstanding mysteries in plant biology. In providing conduits for the exchange of small and large, informational molecules they are central to the growth, development and defence of all higher plants. In the past few years, strategies have been devised for the molecular dissection of plasmodesmal composition and function, and we are beginning to see how these enigmatic structures will become to be understood.
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Affiliation(s)
- Andrew J Maule
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK.
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Verchot-Lubicz J. Plasmodesmata transport of GFP and GFP fusions requires little energy and transitions during leaf expansion. PLANT SIGNALING & BEHAVIOR 2008; 3:902-905. [PMID: 19704536 PMCID: PMC2634411 DOI: 10.4161/psb.3.10.6600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 07/14/2008] [Indexed: 05/28/2023]
Abstract
Plasmodesmata (Pd) are symplastic channels between neighboring plant cells and are key in plant cell-cell signaling. Viruses of proteins, nucleic acids, and a wide range of signaling macromolecules move across Pd. Protein transport Pd is regulated by development and biotic signals. Recent investigations utilizing the Arrhenius equation or Coefficient of conductivity showed that fundamental energetic measurements used to describe transport of proteins across membrane pores or the nuclear pore can also apply to protein movement across Pd. As leaves continue to expand, Pd transport of proteins declines which may result from changes in cell volume, Pd density or Pd structure.
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Affiliation(s)
- Jeanmarie Verchot-Lubicz
- Department of Entomology and Plant Pathology; Noble Research Center; Oklahoma State University; Stillwater, Oklahoma USA
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