151
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Abou-Saleh RH, Hernandez-Gomez MC, Amsbury S, Paniagua C, Bourdon M, Miyashima S, Helariutta Y, Fuller M, Budtova T, Connell SD, Ries ME, Benitez-Alfonso Y. Interactions between callose and cellulose revealed through the analysis of biopolymer mixtures. Nat Commun 2018; 9:4538. [PMID: 30382102 PMCID: PMC6208431 DOI: 10.1038/s41467-018-06820-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 09/21/2018] [Indexed: 01/28/2023] Open
Abstract
The properties of (1,3)-β-glucans (i.e., callose) remain largely unknown despite their importance in plant development and defence. Here we use mixtures of (1,3)-β-glucan and cellulose, in ionic liquid solution and hydrogels, as proxies to understand the physico-mechanical properties of callose. We show that after callose addition the stiffness of cellulose hydrogels is reduced at a greater extent than predicted from the ideal mixing rule (i.e., the weighted average of the individual components’ properties). In contrast, yield behaviour after the elastic limit is more ductile in cellulose-callose hydrogels compared with sudden failure in 100% cellulose hydrogels. The viscoelastic behaviour and the diffusion of the ions in mixed ionic liquid solutions strongly indicate interactions between the polymers. Fourier-transform infrared analysis suggests that these interactions impact cellulose organisation in hydrogels and cell walls. We conclude that polymer interactions alter the properties of callose-cellulose mixtures beyond what it is expected by ideal mixing. Despite their importance in plant development and defence the properties of (1,3)-β-glucan remain largely unknown. Here, the authors find that addition of (1,3)-β-glucans increases the flexibility of cellulose and its resilience to high strain, an effect originating in molecular level interactions.
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Affiliation(s)
- Radwa H Abou-Saleh
- Centre for Plant Science, School of Biology, University of Leeds, Leeds, LS2 9JT, UK.,Faculty of Science, Biophysics Division, Department of Physics, Mansoura University, Mansoura, Egypt
| | | | - Sam Amsbury
- Centre for Plant Science, School of Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Candelas Paniagua
- Centre for Plant Science, School of Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Matthieu Bourdon
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK
| | - Shunsuke Miyashima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Ykä Helariutta
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK
| | - Martin Fuller
- Centre for Plant Science, School of Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Tatiana Budtova
- MINES ParisTech, Centre for Material Forming (CEMEF), PSL Research University, UMR CNRS 7635, CS 10207, 06904, Sophia Antipolis, France
| | - Simon D Connell
- Molecular and Nanoscale Physics Group, School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Michael E Ries
- Soft Matter Physics Research Group, School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
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152
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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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153
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Hofhuis HF, Heidstra R. Transcription factor dosage: more or less sufficient for growth. CURRENT OPINION IN PLANT BIOLOGY 2018; 45:50-58. [PMID: 29852330 DOI: 10.1016/j.pbi.2018.05.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/26/2018] [Accepted: 05/12/2018] [Indexed: 06/08/2023]
Abstract
Recent findings highlight three instances in which major aspects of plant development are controlled by dosage-dependent protein levels. In the shoot apical meristem the mobile transcription factor WUS displays an intricate function with respect to target regulation that involves WUS dosage, binding site affinity and protein dimerization. The size of the root meristem is controlled by dosage-dependent PLT protein activity. Recent identification of targets and feedbacks provide new insights and entry into possible mechanisms of dosage read-out. Finally, HD-ZIPIII dosage, enforced by a gradient of mobile miRNAs, presents a relatively unexplored case in the radial patterning of vasculature and ground tissue. We evaluate our current knowledge of these three examples and address molecular mechanisms of dosage translation where possible.
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Affiliation(s)
- Hugo F Hofhuis
- Department of Plant Sciences, Wageningen University Research, Netherlands
| | - Renze Heidstra
- Department of Plant Sciences, Wageningen University Research, Netherlands.
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154
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Lai YS, Stefano G, Zemelis-Durfee S, Ruberti C, Gibbons L, Brandizzi F. Systemic signaling contributes to the unfolded protein response of the plant endoplasmic reticulum. Nat Commun 2018; 9:3918. [PMID: 30254194 PMCID: PMC6156401 DOI: 10.1038/s41467-018-06289-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 08/29/2018] [Indexed: 01/06/2023] Open
Abstract
The unfolded protein response (UPR) of the endoplasmic reticulum constitutes a conserved and essential cytoprotective pathway designed to survive biotic and abiotic stresses that alter the proteostasis of the endoplasmic reticulum. The UPR is typically considered cell-autonomous and it is yet unclear whether it can also act systemically through non-cell autonomous signaling. We have addressed this question using a genetic approach coupled with micro-grafting and a suite of molecular reporters in the model plant species Arabidopsis thaliana. We show that the UPR has a non-cell autonomous component, and we demonstrate that this is partially mediated by the intercellular movement of the UPR transcription factor bZIP60 facilitating systemic UPR signaling. Therefore, in multicellular eukaryotes such as plants, non-cell autonomous UPR signaling relies on the systemic movement of at least a UPR transcriptional modulator.
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Affiliation(s)
- Ya-Shiuan Lai
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Cell and Molecular Biology Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Giovanni Stefano
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Plant Biology Department, Michigan State University, East Lansing, MI, 48824, USA
| | - Starla Zemelis-Durfee
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
- Plant Biology Department, Michigan State University, East Lansing, MI, 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824, USA
| | - Cristina Ruberti
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
| | - Lizzie Gibbons
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA
| | - Federica Brandizzi
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, 48824, USA.
- Plant Biology Department, Michigan State University, East Lansing, MI, 48824, USA.
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824, USA.
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155
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Rojek J, Kapusta M, Kozieradzka-Kiszkurno M, Majcher D, Górniak M, Sliwinska E, Sharbel TF, Bohdanowicz J. Establishing the cell biology of apomictic reproduction in diploid Boechera stricta (Brassicaceae). ANNALS OF BOTANY 2018; 122:513-539. [PMID: 29982367 PMCID: PMC6153484 DOI: 10.1093/aob/mcy114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/21/2018] [Indexed: 05/15/2023]
Abstract
Background and aims In the Brassicaceae family, apomictic development is characteristic of the genus Boechera. Hybridization, polyploidy and environmental adaptation that arose during the evolution of Boechera may serve as (epi)genetic regulators of apomictic initiation in this genus. Here we focus on Boechera stricta, a predominantly diploid species that reproduces sexually. However, apomictic development in this species has been reported in several studies, indicating non-obligate sexuality. Methods A progressive investigation of flower development was conducted using three accessions to assess the reproductive system of B. stricta. We employed molecular and cyto-embryological identification using histochemistry, transmission electron microscopy and Nomarski and epifluorescence microscopy. Key Results Data from internal transcribed spacer (ITS) and chloroplast haplotype sequencing, in addition to microsatellite variation, confirmed the B. stricta genotype for all lines. Embryological data indicated irregularities in sexual reproduction manifested by heterochronic ovule development, longevity of meiocyte and dyad stages, diverse callose accumulation during meiocyte-to-gametophyte development, and the formation of triads and tetrads in several patterns. The arabinogalactan-related sugar epitope recognized by JIM13 immunolocalized to one or more megaspores. Furthermore, pollen sterility and a high frequency of seed abortion appeared to accompany reproduction of the accession ES512, along with the initiation of parthenogenesis. Data from flow cytometric screening revealed both sexual and apomictic seed formation. Conclusion These results imply that B. stricta is a species with an underlying ability to initiate apomixis, at least with respect to the lines examined here. The existence of apomixis in an otherwise diploid sexual B. stricta may provide the genomic building blocks for establishing highly penetrant apomictic diploids and hybrid relatives. Our findings demonstrate that apomixis per se is a variable trait upon which natural selection could act.
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Affiliation(s)
- Joanna Rojek
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, Poland
| | - Małgorzata Kapusta
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, Poland
| | | | - Daria Majcher
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, Poland
| | - Marcin Górniak
- Department of Molecular Evolution, Faculty of Biology, University of Gdańsk, Poland
| | - Elwira Sliwinska
- Laboratory of Molecular Biology and Cytometry, Department of Agricultural Biotechnology, UTP University of Technology and Life Sciences in Bydgoszcz, Poland
| | - Timothy F Sharbel
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Jerzy Bohdanowicz
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, Poland
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156
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Feeding the Walls: How Does Nutrient Availability Regulate Cell Wall Composition? Int J Mol Sci 2018; 19:ijms19092691. [PMID: 30201905 PMCID: PMC6164997 DOI: 10.3390/ijms19092691] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 01/12/2023] Open
Abstract
Nutrients are critical for plants to grow and develop, and nutrient depletion severely affects crop yield. In order to optimize nutrient acquisition, plants adapt their growth and root architecture. Changes in growth are determined by modifications in the cell walls surrounding every plant cell. The plant cell wall, which is largely composed of complex polysaccharides, is essential for plants to attain their shape and to protect cells against the environment. Within the cell wall, cellulose strands form microfibrils that act as a framework for other wall components, including hemicelluloses, pectins, proteins, and, in some cases, callose, lignin, and suberin. Cell wall composition varies, depending on cell and tissue type. It is governed by synthesis, deposition and remodeling of wall components, and determines the physical and structural properties of the cell wall. How nutrient status affects cell wall synthesis and organization, and thus plant growth and morphology, remains poorly understood. In this review, we aim to summarize and synthesize research on the adaptation of root cell walls in response to nutrient availability and the potential role of cell walls in nutrient sensing.
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157
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Pierre-Jerome E, Drapek C, Benfey PN. Regulation of Division and Differentiation of Plant Stem Cells. Annu Rev Cell Dev Biol 2018; 34:289-310. [PMID: 30134119 DOI: 10.1146/annurev-cellbio-100617-062459] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A major challenge in developmental biology is unraveling the precise regulation of plant stem cell maintenance and the transition to a fully differentiated cell. In this review, we highlight major themes coordinating the acquisition of cell identity and subsequent differentiation in plants. Plant cells are immobile and establish position-dependent cell lineages that rely heavily on external cues. Central players are the hormones auxin and cytokinin, which balance cell division and differentiation during organogenesis. Transcription factors and miRNAs, many of which are mobile in plants, establish gene regulatory networks that communicate cell position and fate. Small peptide signaling also provides positional cues as new cell types emerge from stem cell division and progress through differentiation. These pathways recruit similar players for patterning different organs, emphasizing the modular nature of gene regulatory networks. Finally, we speculate on the outstanding questions in the field and discuss how they may be addressed by emerging technologies.
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Affiliation(s)
- Edith Pierre-Jerome
- Department of Biology and Howard Hughes Medical Institute, Duke University, Durham, North Carolina 27708, USA;
| | - Colleen Drapek
- Department of Biology and Howard Hughes Medical Institute, Duke University, Durham, North Carolina 27708, USA;
| | - Philip N Benfey
- Department of Biology and Howard Hughes Medical Institute, Duke University, Durham, North Carolina 27708, USA;
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158
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Gating of miRNA movement at defined cell-cell interfaces governs their impact as positional signals. Nat Commun 2018; 9:3107. [PMID: 30082703 PMCID: PMC6079027 DOI: 10.1038/s41467-018-05571-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/13/2018] [Indexed: 01/02/2023] Open
Abstract
Mobile small RNAs serve as local positional signals in development and coordinate stress responses across the plant. Despite its central importance, an understanding of how the cell-to-cell movement of small RNAs is governed is lacking. Here, we show that miRNA mobility is precisely regulated through a gating mechanism polarised at defined cell–cell interfaces. This generates directional movement between neighbouring cells that limits long-distance shoot-to-root trafficking, and underpins domain-autonomous behaviours of small RNAs within stem cell niches. We further show that the gating of miRNA mobility occurs independent of mechanisms controlling protein movement, identifying the small RNA as the mobile unit. These findings reveal gate-keepers of cell-to-cell small RNA mobility generate selectivity in long-distance signalling, and help safeguard functional domains within dynamic stem cell niches while mitigating a ‘signalling gridlock’ in contexts where developmental patterning events occur in close spatial and temporal vicinity. Movement of small RNA between cells is critical to plant development and stress responses. Here the authors uncover a gate-keeping mechanism that can restrict small RNA movement at cell-cell interfaces, providing selectivity in long-distance signalling and limiting the scope of local mobility.
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159
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Julius BT, Slewinski TL, Baker RF, Tzin V, Zhou S, Bihmidine S, Jander G, Braun DM. Maize Carbohydrate partitioning defective1 impacts carbohydrate distribution, callose accumulation, and phloem function. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3917-3931. [PMID: 29846660 PMCID: PMC6054164 DOI: 10.1093/jxb/ery203] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/18/2018] [Indexed: 05/19/2023]
Abstract
Plants synthesize carbohydrates in photosynthetic tissues, with the majority of plants transporting sucrose to non-photosynthetic tissues to sustain growth and development. While the anatomical, biochemical, and physiological processes regulating sucrose long-distance transport are well characterized, little is known concerning the genes controlling whole-plant carbohydrate partitioning. To identify loci influencing carbon export from leaves, we screened mutagenized maize plants for phenotypes associated with reduced carbohydrate transport, including chlorosis and excessive starch and soluble sugars in leaves. Carbohydrate partitioning defective1 (Cpd1) was identified as a semi-dominant mutant exhibiting these phenotypes. Phloem transport experiments suggested that the hyperaccumulation of starch and soluble sugars in the Cpd1/+ mutant leaves was due to inhibited sucrose export. Interestingly, ectopic callose deposits were observed in the phloem of mutant leaves, and probably underlie the decreased transport. In addition to the carbohydrate hyperaccumulation phenotype, Cpd1/+ mutants overaccumulate benzoxazinoid defense compounds and exhibit increased tolerance when attacked by aphids. However, double mutant studies between Cpd1/+ and benzoxazinoid-less plants indicate that the ectopic callose and carbon hyperaccumulation are independent of benzoxazinoid production. Based on the formation of callose occlusions in the developing phloem, we hypothesize that the cpd1 gene functions early in phloem development, thereby impacting whole-plant carbohydrate partitioning.
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Affiliation(s)
- Benjamin T Julius
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
| | - Thomas L Slewinski
- Department of Biology, Pennsylvania State University, State College, PA, USA
| | - R Frank Baker
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
| | - Vered Tzin
- Boyce Thompson Institute, Ithaca, NY, USA
| | | | - Saadia Bihmidine
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
| | | | - David M Braun
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, MO, USA
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160
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Benítez M, Hernández-Hernández V, Newman SA, Niklas KJ. Dynamical Patterning Modules, Biogeneric Materials, and the Evolution of Multicellular Plants. FRONTIERS IN PLANT SCIENCE 2018; 9:871. [PMID: 30061903 PMCID: PMC6055014 DOI: 10.3389/fpls.2018.00871] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/04/2018] [Indexed: 05/18/2023]
Abstract
Comparative analyses of developmental processes across a broad spectrum of organisms are required to fully understand the mechanisms responsible for the major evolutionary transitions among eukaryotic photosynthetic lineages (defined here as the polyphyletic algae and the monophyletic land plants). The concepts of dynamical patterning modules (DPMs) and biogeneric materials provide a framework for studying developmental processes in the context of such comparative analyses. In the context of multicellularity, DPMs are defined as sets of conserved gene products and molecular networks, in conjunction with the physical morphogenetic and patterning processes they mobilize. A biogeneric material is defined as mesoscale matter with predictable morphogenetic capabilities that arise from complex cellular conglomerates. Using these concepts, we outline some of the main events and transitions in plant evolution, and describe the DPMs and biogeneric properties associated with and responsible for these transitions. We identify four primary DPMs that played critical roles in the evolution of multicellularity (i.e., the DPMs responsible for cell-to-cell adhesion, identifying the future cell wall, cell differentiation, and cell polarity). Three important conclusions emerge from a broad phyletic comparison: (1) DPMs have been achieved in different ways, even within the same clade (e.g., phycoplastic cell division in the Chlorophyta and phragmoplastic cell division in the Streptophyta), (2) DPMs had their origins in the co-option of molecular species present in the unicellular ancestors of multicellular plants, and (3) symplastic transport mediated by intercellular connections, particularly plasmodesmata, was critical for the evolution of complex multicellularity in plants.
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Affiliation(s)
- Mariana Benítez
- Centro de Ciencias de la Complejidad – Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Valeria Hernández-Hernández
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, École Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Lyon, France
| | - Stuart A. Newman
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, United States
| | - Karl J. Niklas
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
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161
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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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162
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Abstract
Plasmodesmata are cytoplasmic communication channels that are vital for the physiology and development of all plants. They facilitate the intercellular movement of various cargos - ranging from small molecules, such as sugars, ions and other essential nutrients and chemicals, to large complex molecules, such as proteins and different types of RNA species - by bridging neighboring cells across their cell walls. Structurally, an individual channel consists of the cytoplasmic sleeve that is formed between the endoplasmic reticulum and the plasma membrane leaflets. Plasmodesmata are highly versatile channels; they vary in number and structure, and undergo constant adjustments to their permeability in response to many internal and external cues. In this Cell Science at a Glance article and accompanying poster, we provide an overview of plasmodesmata form and function, with highlights on their development and variation, associated components and mobile factors. In addition, we present methodologies that are currently used to study plasmodesmata-mediated intercellular communication.
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Affiliation(s)
- Ross E Sager
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Jung-Youn Lee
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
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163
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Lu KJ, Danila FR, Cho Y, Faulkner C. Peeking at a plant through the holes in the wall - exploring the roles of plasmodesmata. THE NEW PHYTOLOGIST 2018; 218:1310-1314. [PMID: 29574753 DOI: 10.1111/nph.15130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Plasmodesmata (PD) are membrane-lined pores that connect neighbouring plant cells and allow molecular exchange via the symplast. Past studies have revealed the basic structure of PD, some of the transport mechanisms for molecules through PD, and a variety of physiological processes in which they function. Recently, with the help of newly developed technologies, several exciting new features of PD have been revealed. New PD structures were observed during early formation of PD and between phloem sieve elements and phloem pole pericycle cells in roots. Both observations challenge our current understanding of PD structure and function. Research into novel physiological responses, which are regulated by PD, indicates that we have not yet fully explored the potential contribution of PD to overall plant function. In this Viewpoint article, we summarize some of the recent advances in understanding the structure and function of PD and propose the challenges ahead for the community.
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Affiliation(s)
- Kuan-Ju Lu
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, the Netherlands
| | - Florence R Danila
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Yueh Cho
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Programme, National Chung Hsing University and Academia Sinica, Taipei, 11529, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan
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164
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Gerlitz N, Gerum R, Sauer N, Stadler R. Photoinducible DRONPA-s: a new tool for investigating cell-cell connectivity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:751-766. [PMID: 29654648 DOI: 10.1111/tpj.13918] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/02/2018] [Accepted: 03/26/2018] [Indexed: 06/08/2023]
Abstract
The development of multicellular plants relies on the ability of their cells to exchange solutes, proteins and signalling compounds through plasmodesmata, symplasmic pores in the plant cell wall. The aperture of plasmodesmata is regulated in response to developmental cues or external factors such as pathogen attack. This regulation enables tight control of symplasmic cell-to-cell transport. Here we report on an elegant non-invasive method to quantify the passive movement of protein between selected cells even in deeper tissue layers. The system is based on the fluorescent protein DRONPA-s, which can be switched on and off repeatedly by illumination with different light qualities. Using transgenic 35S::DRONPA-s Arabidopsis thaliana and a confocal microscope it was possible to activate DRONPA-s fluorescence in selected cells of the root meristem. This enabled us to compare movement of DRONPA-s from the activated cells into the respective neighbouring cells. Our analyses showed that pericycle cells display the highest efflux capacity with a good lateral connectivity. In contrast, root cap cells showed the lowest efflux of DRONPA-s. Plasmodesmata of quiescent centre cells mediated a stronger efflux into columella cells than into stele initials. To simplify measurements of fluorescence intensity in a complex tissue we developed software that allows simultaneous analyses of fluorescence intensities of several neighbouring cells. Our DRONPA-s system generates reproducible data and is a valuable tool for studying symplasmic connectivity.
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Affiliation(s)
- Nadja Gerlitz
- Molecular Plant Physiology, University of Erlangen, Staudtstrasse 5, Erlangen, 91058, Germany
| | - Richard Gerum
- Biophysics, University of Erlangen, Henkestrasse 91, Erlangen, 91052, Germany
| | - Norbert Sauer
- Molecular Plant Physiology, University of Erlangen, Staudtstrasse 5, Erlangen, 91058, Germany
| | - Ruth Stadler
- Molecular Plant Physiology, University of Erlangen, Staudtstrasse 5, Erlangen, 91058, Germany
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165
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Tucker MR, Lou H, Aubert MK, Wilkinson LG, Little A, Houston K, Pinto SC, Shirley NJ. Exploring the Role of Cell Wall-Related Genes and Polysaccharides during Plant Development. PLANTS (BASEL, SWITZERLAND) 2018; 7:E42. [PMID: 29857498 PMCID: PMC6028917 DOI: 10.3390/plants7020042] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 12/17/2022]
Abstract
The majority of organs in plants are not established until after germination, when pluripotent stem cells in the growing apices give rise to daughter cells that proliferate and subsequently differentiate into new tissues and organ primordia. This remarkable capacity is not only restricted to the meristem, since maturing cells in many organs can also rapidly alter their identity depending on the cues they receive. One general feature of plant cell differentiation is a change in cell wall composition at the cell surface. Historically, this has been viewed as a downstream response to primary cues controlling differentiation, but a closer inspection of the wall suggests that it may play a much more active role. Specific polymers within the wall can act as substrates for modifications that impact receptor binding, signal mobility, and cell flexibility. Therefore, far from being a static barrier, the cell wall and its constituent polysaccharides can dictate signal transmission and perception, and directly contribute to a cell's capacity to differentiate. In this review, we re-visit the role of plant cell wall-related genes and polysaccharides during various stages of development, with a particular focus on how changes in cell wall machinery accompany the exit of cells from the stem cell niche.
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Affiliation(s)
- Matthew R Tucker
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA 5062, Australia.
| | - Haoyu Lou
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA 5062, Australia.
- Australian Research Council Centre of Excellence in Plant Cell Walls, The University of Adelaide, Glen Osmond, SA 5062, Australia.
| | - Matthew K Aubert
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA 5062, Australia.
- Australian Research Council Centre of Excellence in Plant Cell Walls, The University of Adelaide, Glen Osmond, SA 5062, Australia.
| | - Laura G Wilkinson
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA 5062, Australia.
- Australian Research Council Centre of Excellence in Plant Cell Walls, The University of Adelaide, Glen Osmond, SA 5062, Australia.
| | - Alan Little
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA 5062, Australia.
| | - Kelly Houston
- Cell and Molecular Sciences, The James Hutton Institute, Dundee DD2 5DA, UK.
| | - Sara C Pinto
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal.
| | - Neil J Shirley
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA 5062, Australia.
- Australian Research Council Centre of Excellence in Plant Cell Walls, The University of Adelaide, Glen Osmond, SA 5062, Australia.
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166
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Kehr J, Kragler F. Long distance RNA movement. THE NEW PHYTOLOGIST 2018; 218:29-40. [PMID: 29418002 DOI: 10.1111/nph.15025] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/28/2017] [Indexed: 05/06/2023]
Abstract
Contents Summary 29 I. Introduction 29 II. Phloem as a conduit for macromolecules 30 III. Classes of phloem transported RNAs and their function 32 IV. Mode of RNA transport 35 V. Conclusions 37 Acknowledgements 37 References 37 SUMMARY: In higher plants, small noncoding RNAs and large messenger RNA (mRNA) molecules are transported between cells and over long distances via the phloem. These large macromolecules are thought to get access to the sugar-conducting phloem vessels via specialized plasmodesmata (PD). Analyses of the phloem exudate suggest that all classes of RNA molecules, including silencing-induced RNAs (siRNAs), micro RNAs (miRNAs), transfer RNAs (tRNAs), ribosomal RNA (rRNAs) and mRNAs, are transported via the vasculature to distant tissues. Although the functions of mobile siRNAs and miRNAs as signalling molecules are well established, we lack a profound understanding of mobile mRNA function(s) in recipient cells and tissues, and how they are selected for transport. A surprisingly high number of up to thousands of mRNAs were described in diverse plant species such as cucumber, pumpkin, Arabidopsis and grapevine to move long distances over graft junctions to distinct body parts. In this review, we present an overview of the classes of mobile RNAs, the potential mechanisms facilitating RNA long-distance transport, and the roles of mobile RNAs in regulating transcription and translation. Furthermore, we address potential function(s) of mobile protein-encoding mRNAs with respect to their characteristics and evolutionary constraints.
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Affiliation(s)
- Julia Kehr
- Biocenter Klein Flottbek, Molekulare Pflanzengenetik, University Hamburg, Ohnhorststr. 18, Hamburg 22609, Germany
| | - Friedrich Kragler
- Department II, Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm 14476, Germany
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167
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Liang D. A Salutary Role of Reactive Oxygen Species in Intercellular Tunnel-Mediated Communication. Front Cell Dev Biol 2018; 6:2. [PMID: 29503816 PMCID: PMC5821100 DOI: 10.3389/fcell.2018.00002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/18/2018] [Indexed: 12/17/2022] Open
Abstract
The reactive oxygen species, generally labeled toxic due to high reactivity without target specificity, are gradually uncovered as signaling molecules involved in a myriad of biological processes. But one important feature of ROS roles in macromolecule movement has not caught attention until recent studies with technique advance and design elegance have shed lights on ROS signaling for intercellular and interorganelle communication. This review begins with the discussions of genetic and chemical studies on the regulation of symplastic dye movement through intercellular tunnels in plants (plasmodesmata), and focuses on the ROS regulatory mechanisms concerning macromolecule movement including small RNA-mediated gene silencing movement and protein shuttling between cells. Given the premise that intercellular tunnels (bridges) in mammalian cells are the key physical structures to sustain intercellular communication, movement of macromolecules and signals is efficiently facilitated by ROS-induced membrane protrusions formation, which is analogously applied to the interorganelle communication in plant cells. Although ROS regulatory differences between plant and mammalian cells exist, the basis for ROS-triggered conduit formation underlies a unifying conservative theme in multicellular organisms. These mechanisms may represent the evolutionary advances that have enabled multicellularity to gain the ability to generate and utilize ROS to govern material exchanges between individual cells in oxygenated environment.
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Affiliation(s)
- Dacheng Liang
- Hubei Collaborative Innovation Center for Grain Industry, School of Agriculture, Yangtze University, Jingzhou, China.,Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, Yangtze University, Jingzhou, China
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168
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Lu KJ, De Rybel B, van Mourik H, Weijers D. Regulation of intercellular TARGET OF MONOPTEROS 7 protein transport in the Arabidopsis root. Development 2018; 145:dev.152892. [PMID: 29358212 DOI: 10.1242/dev.152892] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 12/13/2017] [Indexed: 01/24/2023]
Abstract
Intercellular communication coordinates hypophysis establishment in the Arabidopsis embryo. Previously, TARGET OF MONOPTEROS 7 (TMO7) was reported to be transported to the hypophysis, the founder cell of the root cap, and RNA suppression experiments implicated its function in embryonic root development. However, the protein properties and mechanisms mediating TMO7 protein transport, and the role the movement plays in development remained unclear. Here, we report that in the post-embryonic root, TMO7 and its close relatives are transported into the root cap through plasmodesmata in a sequence-dependent manner. We also show that nuclear residence is crucial for TMO7 transport, and postulate that modification, potentially phosphorylation, labels TMO7 for transport. Additionally, three novel CRISPR/Cas9-induced tmo7 alleles confirmed a role in hypophysis division, but suggest complex redundancies with close relatives in root formation. Finally, we demonstrate that TMO7 transport is biologically meaningful, as local expression partially restores hypophysis division in a plasmodesmal protein transport mutant. Our study identifies motifs and amino acids that are pivotal for TMO7 protein transport, and establishes the importance of TMO7 in hypophysis and root development.
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Affiliation(s)
- Kuan-Ju Lu
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Bert De Rybel
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.,Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 927, 9052 Ghent, Belgium.,VIB Center for Plant Systems Biology, Technologiepark 927, 9052 Ghent, Belgium
| | - Hilda van Mourik
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
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169
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Leijon F, Melzer M, Zhou Q, Srivastava V, Bulone V. Proteomic Analysis of Plasmodesmata From Populus Cell Suspension Cultures in Relation With Callose Biosynthesis. FRONTIERS IN PLANT SCIENCE 2018; 9:1681. [PMID: 30510561 PMCID: PMC6252348 DOI: 10.3389/fpls.2018.01681] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/29/2018] [Indexed: 05/19/2023]
Abstract
Plasmodesmata are channels that link adjacent cells in plant tissues through which molecular exchanges take place. They are involved in multiple processes vital to plant cells, such as responses to hormonal signaling or environmental challenges including osmotic stress, wounding and pathogen attack. Despite the importance of plasmodesmata, their proteome is not well-defined. Here, we have isolated fractions enriched in plasmodesmata from cell suspension cultures of Populus trichocarpa and identified 201 proteins that are enriched in these fractions, thereby providing further insight on the multiple functions of plasmodesmata. Proteomics analysis revealed an enrichment of proteins specifically involved in responses to stress, transport, metabolism and signal transduction. Consistent with the role of callose deposition and turnover in the closure and aperture of the plasmodesmata and our proteomic analysis, we demonstrate the enrichment of callose synthase activity in the plasmodesmata represented by several gene products. A new form of calcium-independent callose synthase activity was detected, in addition to the typical calcium-dependent enzyme activity, suggesting a role of calcium in the regulation of plasmodesmata through two forms of callose synthase activities. Our report provides the first proteomic investigation of the plasmodesmata from a tree species and the direct biochemical evidence for the occurrence of several forms of active callose synthases in these structures. Data are available via ProteomeXchange with identifier PXD010692.
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Affiliation(s)
- Felicia Leijon
- Division of Glycoscience, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Michael Melzer
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Qi Zhou
- Division of Glycoscience, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Vaibhav Srivastava
- Division of Glycoscience, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
- *Correspondence: Vaibhav Srivastava, Vincent Bulone,
| | - Vincent Bulone
- Division of Glycoscience, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
- ARC Centre of Excellence in Plant Cell Walls and School of Agriculture, Food and Wine, The University of Adelaide, Adelaide, SA, Australia
- *Correspondence: Vaibhav Srivastava, Vincent Bulone,
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170
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Keppler BD, Song J, Nyman J, Voigt CA, Bent AF. 3-Aminobenzamide Blocks MAMP-Induced Callose Deposition Independently of Its Poly(ADPribosyl)ation Inhibiting Activity. FRONTIERS IN PLANT SCIENCE 2018; 9:1907. [PMID: 30619442 PMCID: PMC6305757 DOI: 10.3389/fpls.2018.01907] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 12/07/2018] [Indexed: 05/15/2023]
Abstract
Cell wall reinforcement with callose is a frequent plant response to infection. Poly(ADP-ribosyl)ation is a protein post-translational modification mediated by poly(ADP-ribose) polymerases (PARPs). Poly(ADP-ribosyl)ation has well-known roles in DNA damage repair and has more recently been shown to contribute to plant immune responses. 3-aminobenzamide (3AB) is an established PARP inhibitor and it blocks the callose deposition elicited by flg22 or elf18, two microbe-associated molecular patterns (MAMPs). However, we report that an Arabidopsis parp1parp2parp3 triple mutant does not exhibit loss of flg22-induced callose deposition. Additionally, the more specific PARP inhibitors PJ-34 and INH2BP inhibit PARP activity in Arabidopsis but do not block MAMP-induced callose deposition. These data demonstrate off-target activity of 3AB and indicate that 3AB inhibits callose deposition through a mechanism other than poly(ADP-ribosyl)ation. POWDERY MILDEW RESISTANT 4 (PMR4) is the callose synthase responsible for the majority of MAMP- and wound-induced callose deposition in Arabidopsis. 3AB does not block wound-induced callose deposition, and 3AB does not reduce the PMR4 mRNA abundance increase in response to flg22. Levels of PMR4-HA protein increase in response to flg22, and increase even more in flg22 + 3AB despite no callose being produced. The callose synthase inhibitor 2-deoxy-D-glucose does not cause similar impacts on PMR4-HA protein levels. Beyond MAMPs, we find that 3AB also reduces callose deposition induced by powdery mildew (Golovinomyces cichoracearum) and impairs the penetration resistance of a PMR4 overexpression line. 3AB thus reveals pathogenesis-associated pathways that activate callose synthase enzymatic activity distinct from those that elevate PMR4 mRNA and protein abundance.
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Affiliation(s)
- Brian D. Keppler
- Department of Plant Pathology, University of Wisconsin–Madison, Madison, WI, United States
| | - Junqi Song
- Department of Plant Pathology, University of Wisconsin–Madison, Madison, WI, United States
| | - Jackson Nyman
- Department of Plant Pathology, University of Wisconsin–Madison, Madison, WI, United States
| | - Christian A. Voigt
- Phytopathology and Biochemistry, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Andrew F. Bent
- Department of Plant Pathology, University of Wisconsin–Madison, Madison, WI, United States
- *Correspondence: Andrew F. Bent,
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171
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Long Y, Stahl Y, Weidtkamp-Peters S, Smet W, Du Y, Gadella TWJ, Goedhart J, Scheres B, Blilou I. Optimizing FRET-FLIM Labeling Conditions to Detect Nuclear Protein Interactions at Native Expression Levels in Living Arabidopsis Roots. FRONTIERS IN PLANT SCIENCE 2018; 9:639. [PMID: 29868092 PMCID: PMC5962846 DOI: 10.3389/fpls.2018.00639] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 04/25/2018] [Indexed: 05/21/2023]
Abstract
Protein complex formation has been extensively studied using Förster resonance energy transfer (FRET) measured by Fluorescence Lifetime Imaging Microscopy (FLIM). However, implementing this technology to detect protein interactions in living multicellular organism at single-cell resolution and under native condition is still difficult to achieve. Here we describe the optimization of the labeling conditions to detect FRET-FLIM in living plants. This study exemplifies optimization procedure involving the identification of the optimal position for the labels either at the N or C terminal region and the selection of the bright and suitable, fluorescent proteins as donor and acceptor labels for the FRET study. With an effective optimization strategy, we were able to detect the interaction between the stem cell regulators SHORT-ROOT and SCARECROW at endogenous expression levels in the root pole of living Arabidopsis embryos and developing lateral roots by FRET-FLIM. Using this approach we show that the spatial profile of interaction between two transcription factors can be highly modulated in reoccurring and structurally resembling organs, thus providing new information on the dynamic redistribution of nuclear protein complex configurations in different developmental stages. In principle, our optimization procedure for transcription factor complexes is applicable to any biological system.
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Affiliation(s)
- Yuchen Long
- Plant Developmental Biology, Wageningen University and Research Centre, Wageningen, Netherlands
| | - Yvonne Stahl
- Institute for Developmental Genetics, Heinrich Heine University, Düsseldorf, Germany
| | | | - Wouter Smet
- Plant Developmental Biology, Wageningen University and Research Centre, Wageningen, Netherlands
| | - Yujuan Du
- Plant Developmental Biology, Wageningen University and Research Centre, Wageningen, Netherlands
| | - Theodorus W. J. Gadella
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Joachim Goedhart
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Ben Scheres
- Plant Developmental Biology, Wageningen University and Research Centre, Wageningen, Netherlands
| | - Ikram Blilou
- Plant Developmental Biology, Wageningen University and Research Centre, Wageningen, Netherlands
- Plant Cell and Developmental Biology, King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering (BESE), Thuwal, Saudi Arabia
- *Correspondence: Ikram Blilou
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172
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173
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Nicolas WJ, Grison MS, Bayer EM. Shaping intercellular channels of plasmodesmata: the structure-to-function missing link. JOURNAL OF EXPERIMENTAL BOTANY 2017; 69:91-103. [PMID: 28992136 DOI: 10.1093/jxb/erx225] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
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.
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Affiliation(s)
- William J Nicolas
- Laboratoire de Biogénèse Membranaire, UMR 5200 CNRS, University of Bordeaux, France
| | - Magali S Grison
- Laboratoire de Biogénèse Membranaire, UMR 5200 CNRS, University of Bordeaux, France
| | - Emmanuelle M Bayer
- Laboratoire de Biogénèse Membranaire, UMR 5200 CNRS, University of Bordeaux, France
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174
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Amsbury S, Kirk P, Benitez-Alfonso Y. Emerging models on the regulation of intercellular transport by plasmodesmata-associated callose. JOURNAL OF EXPERIMENTAL BOTANY 2017; 69:105-115. [PMID: 29040641 DOI: 10.1093/jxb/erx337] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The intercellular transport of molecules through membranous channels that traverse the cell walls-so-called plasmodesmata-is of fundamental importance for plant development. Regulation of plasmodesmata aperture (and transport capacity) is mediated by changes in the flanking cell walls, mainly via the synthesis/degradation (turnover) of the (1,3)-β-glucan polymer callose. The role of callose in organ development and in plant environmental responses is well recognized, but detailed understanding of the mechanisms regulating its accumulation and its effects on the structure and permeability of the channels is still missing. We compiled information on the molecular components and signalling pathways involved in callose turnover at plasmodesmata and, more generally, on the structural and mechanical properties of (1,3)-β-glucan polymers in cell walls. Based on this revision, we propose models integrating callose, cell walls, and the regulation of plasmodesmata structure and intercellular communication. We also highlight new tools and interdisciplinary approaches that can be applied to gain further insight into the effects of modifying callose in cell walls and its consequences for intercellular signalling.
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Affiliation(s)
- Sam Amsbury
- Centre for Plant Science, School of Biology, University of Leeds, UK
| | - Philip Kirk
- Centre for Plant Science, School of Biology, University of Leeds, UK
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175
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Gao YQ, Chen JG, Chen ZR, An D, Lv QY, Han ML, Wang YL, Salt DE, Chao DY. A new vesicle trafficking regulator CTL1 plays a crucial role in ion homeostasis. PLoS Biol 2017; 15:e2002978. [PMID: 29284002 PMCID: PMC5746208 DOI: 10.1371/journal.pbio.2002978] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Ion homeostasis is essential for plant growth and environmental adaptation, and maintaining ion homeostasis requires the precise regulation of various ion transporters, as well as correct root patterning. However, the mechanisms underlying these processes remain largely elusive. Here, we reported that a choline transporter gene, CTL1, controls ionome homeostasis by regulating the secretory trafficking of proteins required for plasmodesmata (PD) development, as well as the transport of some ion transporters. Map-based cloning studies revealed that CTL1 mutations alter the ion profile of Arabidopsis thaliana. We found that the phenotypes associated with these mutations are caused by a combination of PD defects and ion transporter misregulation. We also established that CTL1 is involved in regulating vesicle trafficking and is thus required for the trafficking of proteins essential for ion transport and PD development. Characterizing choline transporter-like 1 (CTL1) as a new regulator of protein sorting may enable researchers to understand not only ion homeostasis in plants but also vesicle trafficking in general.
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Affiliation(s)
- Yi-Qun Gao
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiu-Geng Chen
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zi-Ru Chen
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dong An
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qiao-Yan Lv
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mei-Ling Han
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ya-Ling Wang
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - David E. Salt
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Dai-Yin Chao
- National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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176
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Kawade K, Tanimoto H, Horiguchi G, Tsukaya H. Spatially Different Tissue-Scale Diffusivity Shapes ANGUSTIFOLIA3 Gradient in Growing Leaves. Biophys J 2017; 113:1109-1120. [PMID: 28877493 DOI: 10.1016/j.bpj.2017.06.072] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 12/01/2022] Open
Abstract
The spatial gradient of signaling molecules is pivotal for establishing developmental patterns of multicellular organisms. It has long been proposed that these gradients could arise from the pure diffusion process of signaling molecules between cells, but whether this simplest mechanism establishes the formation of the tissue-scale gradient remains unclear. Plasmodesmata are unique channel structures in plants that connect neighboring cells for molecular transport. In this study, we measured cellular- and tissue-scale kinetics of molecular transport through plasmodesmata in Arabidopsis thaliana developing leaf primordia by fluorescence recovery assays. These trans-scale measurements revealed biophysical properties of diffusive molecular transport through plasmodesmata and revealed that the tissue-scale diffusivity, but not the cellular-scale diffusivity, is spatially different along the leaf proximal-to-distal axis. We found that the gradient in cell size along the developmental axis underlies this spatially different tissue-scale diffusivity. We then asked how this diffusion-based framework functions in establishing a signaling gradient of endogenous molecules. ANGUSTIFOLIA3 (AN3) is a transcriptional co-activator, and as we have shown here, it forms a long-range signaling gradient along the leaf proximal-to-distal axis to determine a cell-proliferation domain. By genetically engineering AN3 mobility, we assessed each contribution of cell-to-cell movement and tissue growth to the distribution of the AN3 gradient. We constructed a diffusion-based theoretical model using these quantitative data to analyze the AN3 gradient formation and demonstrated that it could be achieved solely by the diffusive molecular transport in a growing tissue. Our results indicate that the spatially different tissue-scale diffusivity is a core mechanism for AN3 gradient formation. This provides evidence that the pure diffusion process establishes the formation of the long-range signaling gradient in leaf development.
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Affiliation(s)
- Kensuke Kawade
- Okazaki Institute for Integrative Bioscience, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan; National Institute for Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan; Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan.
| | | | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan; Research Center for Life Science, Rikkyo University, Tokyo, Japan
| | - Hirokazu Tsukaya
- Okazaki Institute for Integrative Bioscience, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan; Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
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177
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Záveská Drábková L, Honys D. Evolutionary history of callose synthases in terrestrial plants with emphasis on proteins involved in male gametophyte development. PLoS One 2017; 12:e0187331. [PMID: 29131847 PMCID: PMC5683620 DOI: 10.1371/journal.pone.0187331] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/17/2017] [Indexed: 11/30/2022] Open
Abstract
Callose is a plant-specific polysaccharide (β-1,3-glucan) playing an important role in angiosperms in many developmental processes and responses to biotic and abiotic stresses. Callose is synthesised at the plasma membrane of plant cells by callose synthase (CalS) and, among others, represents the main polysaccharide in the callose wall surrounding the tetrads of developing microspores and in the growing pollen tube wall. CalS proteins involvement in spore development is a plesiomorphic feature of terrestrial plants, but very little is known about their evolutionary origin and relationships amongst the members of this protein family. We performed thorough comparative analyses of callose synthase family proteins from major plant lineages to determine their evolutionary history across the plant kingdom. A total of 1211 candidate CalS sequences were identified and compared amongst diverse taxonomic groups of plants, from bryophytes to angiosperms. Phylogenetic analyses identified six main clades of CalS proteins and suggested duplications during the evolution of specialised functions. Twelve family members had previously been identified in Arabidopsis thaliana. We focused on five CalS subfamilies directly linked to pollen function and found that proteins expressed in pollen evolved twice. CalS9/10 and CalS11/12 formed well-defined clades, whereas pollen-specific CalS5 was found within subfamilies that mostly did not express in mature pollen vegetative cell, although were found in sperm cells. Expression of five out of seven mature pollen-expressed CalS genes was affected by mutations in bzip transcription factors. Only three subfamilies, CalS5, CalS10, and CalS11, however, formed monophyletic, mostly conserved clades. The pairs CalS9/CalS10, CalS11/CalS12 and CalS3 may have diverged after angiosperms diversified from lycophytes and bryophytes. Our analysis of fully sequenced plant proteins identified new evolutionary lineages of callose synthase subfamilies and has established a basis for understanding their functional evolution in terrestrial plants.
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Affiliation(s)
- Lenka Záveská Drábková
- Laboratory of Pollen Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, Praha 6, Czech Republic
- * E-mail: (LZD); (DH)
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, Praha 6, Czech Republic
- * E-mail: (LZD); (DH)
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178
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Fernández-Crespo E, Navarro JA, Serra-Soriano M, Finiti I, García-Agustín P, Pallás V, González-Bosch C. Hexanoic Acid Treatment Prevents Systemic MNSV Movement in Cucumis melo Plants by Priming Callose Deposition Correlating SA and OPDA Accumulation. FRONTIERS IN PLANT SCIENCE 2017; 8:1793. [PMID: 29104580 PMCID: PMC5655017 DOI: 10.3389/fpls.2017.01793] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 10/02/2017] [Indexed: 05/25/2023]
Abstract
Unlike fungal and bacterial diseases, no direct method is available to control viral diseases. The use of resistance-inducing compounds can be an alternative strategy for plant viruses. Here we studied the basal response of melon to Melon necrotic spot virus (MNSV) and demonstrated the efficacy of hexanoic acid (Hx) priming, which prevents the virus from systemically spreading. We analysed callose deposition and the hormonal profile and gene expression at the whole plant level. This allowed us to determine hormonal homeostasis in the melon roots, cotyledons, hypocotyls, stems and leaves involved in basal and hexanoic acid-induced resistance (Hx-IR) to MNSV. Our data indicate important roles of salicylic acid (SA), 12-oxo-phytodienoic acid (OPDA), jasmonic-isoleucine, and ferulic acid in both responses to MNSV. The hormonal and metabolites balance, depending on the time and location associated with basal and Hx-IR, demonstrated the reprogramming of plant metabolism in MNSV-inoculated plants. The treatment with both SA and OPDA prior to virus infection significantly reduced MNSV systemic movement by inducing callose deposition. This demonstrates their relevance in Hx-IR against MNSV and a high correlation with callose deposition. Our data also provide valuable evidence to unravel priming mechanisms by natural compounds.
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Affiliation(s)
- Emma Fernández-Crespo
- Grupo de Bioquímica y Biotecnología, Área de Fisiología Vegetal, Universitat Jaume I, Castellon de la Plana, Spain
| | - Jose A. Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Valencia, Spain
| | - Marta Serra-Soriano
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Valencia, Spain
| | - Iván Finiti
- Departament de Bioquímica, Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Universitat de València, Valencia, Spain
| | - Pilar García-Agustín
- Grupo de Bioquímica y Biotecnología, Área de Fisiología Vegetal, Universitat Jaume I, Castellon de la Plana, Spain
| | - Vicente Pallás
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Valencia, Spain
| | - Carmen González-Bosch
- Departament de Bioquímica, Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Universitat de València, Valencia, Spain
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179
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Collum TD, Culver JN. Tobacco mosaic virus infection disproportionately impacts phloem associated translatomes in Arabidopsis thaliana and Nicotiana benthamiana. Virology 2017; 510:76-89. [PMID: 28710959 DOI: 10.1016/j.virol.2017.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/27/2017] [Accepted: 07/03/2017] [Indexed: 02/07/2023]
Abstract
In this study we use vascular specific promoters and a translating ribosome affinity purification strategy to identify phloem associated translatome responses to infection by tobacco mosaic virus (TMV) in systemic hosts Arabidopsis thaliana ecotype Shahdara and Nicotiana benthamiana. Results demonstrate that in both hosts the number of translatome gene alterations that occurred in response to infection is at least four fold higher in phloem specific translatomes than in non-phloem translatomes. This finding indicates that phloem functions as a key responsive tissue to TMV infection. In addition, host comparisons of translatome alterations reveal both similarities and differences in phloem responses to infection, representing both conserved virus induced phloem alterations involved in promoting infection and virus spread as well as host specific alterations that reflect differences in symptom responses. Combined these results suggest phloem tissues play a disproportion role in the mediation and control of host responses to virus infection.
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Affiliation(s)
- Tamara D Collum
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - James N Culver
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA.
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180
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Lora J, Herrero M, Tucker MR, Hormaza JI. The transition from somatic to germline identity shows conserved and specialized features during angiosperm evolution. THE NEW PHYTOLOGIST 2017; 216:495-509. [PMID: 27878998 DOI: 10.1111/nph.14330] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/13/2016] [Indexed: 05/27/2023]
Abstract
How and why specific plant cells adopt germline identity during ovule development has proved challenging to address, and the pathways that are active in the ovules of basal/early-divergent angiosperms possessing a multilayered nucellus are still unclear. Here, we compare megasporogenesis between two early-divergent angiosperms (Annona cherimola and Persea americana) and the evolutionarily derived Arabidopsis thaliana, studying the three-dimensional spatial position of the megaspore mother cell (MMC), the compositional details of the MMC wall and the location of PIN1 expression. Specific wall polymers distinguished the central position of the MMC and its meiotic products from surrounding tissues in early-divergent angiosperms, whereas, in A. thaliana, only callose (in mature MMCs) and arabinogalactan proteins (AGPs) (in megaspores) distinguished the germline. However, PIN1 expression, which regulates polar auxin transport, was observed around the MMC in the single-layer nucellus of A. thaliana and in the multilayered nucellus of A. cherimola, or close to the MMC in P. americana. The data reveal a similar microenvironment in relation to auxin during megasporogenesis in all three species. However, the different wall polymers that mark MMC fate in early-divergent angiosperms may reflect a specific response to mechanical stress during differentiation, or the specific recruitment of polymers to sustain MMC growth.
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Affiliation(s)
- Jorge Lora
- Department of Subtropical Fruits, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Algarrobo-Costa, 29750, Málaga, Spain
| | - María Herrero
- Department of Pomology, Estación Experimental Aula Dei, CSIC, Apdo. 13034, Zaragoza, 50080, Spain
| | - Matthew R Tucker
- Australian Research Council Centre of Excellence in Plant Cell Walls and School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - José I Hormaza
- Department of Subtropical Fruits, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Algarrobo-Costa, 29750, Málaga, Spain
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181
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Stavolone L, Lionetti V. Extracellular Matrix in Plants and Animals: Hooks and Locks for Viruses. Front Microbiol 2017; 8:1760. [PMID: 28955324 PMCID: PMC5600933 DOI: 10.3389/fmicb.2017.01760] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 08/30/2017] [Indexed: 01/15/2023] Open
Abstract
The extracellular matrix (ECM) of animal and plants cells plays important roles in viral diseases. While in animal cells extracellular matrix components can be exploited by viruses for recognition, attachment and entry, the plant cell wall acts as a physical barrier to viral entry and adds a higher level of difficulty to intercellular movement of viruses. Interestingly, both in plant and animal systems, ECM can be strongly remodeled during virus infection, and the understanding of remodeling mechanisms and molecular players offers new perspectives for therapeutic intervention. This review focuses on the different roles played by the ECM in plant and animal hosts during virus infection with special emphasis on the similarities and differences. Possible biotechnological applications aimed at improving viral resistance are discussed.
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Affiliation(s)
- Livia Stavolone
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle RicercheBari, Italy.,International Institute of Tropical AgricultureIbadan, Nigeria
| | - Vincenzo Lionetti
- Dipartimento di Biologia e Biotecnologie "C. Darwin", "Sapienza" Università di RomaRome, Italy
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182
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Gu Y, Zavaliev R, Dong X. Membrane Trafficking in Plant Immunity. MOLECULAR PLANT 2017; 10:1026-1034. [PMID: 28698057 PMCID: PMC5673114 DOI: 10.1016/j.molp.2017.07.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/02/2017] [Accepted: 07/03/2017] [Indexed: 05/20/2023]
Abstract
Plants employ sophisticated mechanisms to interact with pathogenic as well as beneficial microbes. Of those, membrane trafficking is key in establishing a rapid and precise response. Upon interaction with pathogenic microbes, surface-localized immune receptors undergo endocytosis for signal transduction and activity regulation while cell wall components, antimicrobial compounds, and defense proteins are delivered to pathogen invasion sites through polarized secretion. To sustain mutualistic associations, host cells also reprogram the membrane trafficking system to accommodate invasive structures of symbiotic microbes. Here, we provide an analysis of recent advances in understanding the roles of secretory and endocytic membrane trafficking pathways in plant immune activation. We also discuss strategies deployed by adapted microbes to manipulate these pathways to subvert or inhibit plant defense.
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Affiliation(s)
- Yangnan Gu
- Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China; Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA.
| | - Raul Zavaliev
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
| | - Xinnian Dong
- Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC 27708, USA
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183
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Drapek C, Sparks EE, Benfey PN. Uncovering Gene Regulatory Networks Controlling Plant Cell Differentiation. Trends Genet 2017; 33:529-539. [PMID: 28647055 PMCID: PMC5522350 DOI: 10.1016/j.tig.2017.05.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 05/17/2017] [Accepted: 05/18/2017] [Indexed: 01/05/2023]
Abstract
The development of multicellular organisms relies on the precise regulation of cellular differentiation. As such, there has been significant effort invested to understand the process through which an immature cell undergoes differentiation. In this review, we highlight key discoveries and advances that have contributed to our understanding of the transcriptional networks underlying Arabidopsis root endodermal differentiation. To conclude, we propose perspectives on how advances in molecular biology, microscopy, and nucleotide sequencing will provide the tools to test the biological significance of these gene regulatory networks (GRN).
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Affiliation(s)
| | | | - Philip N Benfey
- Duke University, Durham, NC 27708, USA; Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA.
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184
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Wang M, Thomas N, Jin H. Cross-kingdom RNA trafficking and environmental RNAi for powerful innovative pre- and post-harvest plant protection. CURRENT OPINION IN PLANT BIOLOGY 2017; 38:133-141. [PMID: 28570950 PMCID: PMC5720367 DOI: 10.1016/j.pbi.2017.05.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 05/19/2023]
Abstract
Small RNA (sRNA) induces RNA interference (RNAi) in almost all eukaryotes. While sRNAs can move within an organism, they can also move between interacting organisms to induce gene silencing, a phenomenon called 'cross-kingdom RNAi'. Some sRNAs from pathogens or pests move into host cells and suppress host immunity in both plants and animals; whereas some host sRNAs travel into pathogen/pest cells to inhibit their virulence. Moreover, uptake of exogenous RNAs from the environment was recently discovered in certain fungal pathogens, which makes it possible to suppress fungal diseases by directly applying pathogen-targeting RNAs on crops and post-harvest products. This new-generation of RNA-based fungicides is powerful, environmentally friendly, and can be easily adapted to control multiple diseases simultaneously.
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Affiliation(s)
- Ming Wang
- Department of Plant Pathology & Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, United States
| | - Nicholas Thomas
- Department of Plant Pathology & Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, United States
| | - Hailing Jin
- Department of Plant Pathology & Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, United States.
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185
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In vivo FRET-FLIM reveals cell-type-specific protein interactions in Arabidopsis roots. Nature 2017; 548:97-102. [PMID: 28746306 DOI: 10.1038/nature23317] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 06/19/2017] [Indexed: 01/04/2023]
Abstract
During multicellular development, specification of distinct cell fates is often regulated by the same transcription factors operating differently in distinct cis-regulatory modules, either through different protein complexes, conformational modification of protein complexes, or combinations of both. Direct visualization of different transcription factor complex states guiding specific gene expression programs has been challenging. Here we use in vivo FRET-FLIM (Förster resonance energy transfer measured by fluorescence lifetime microscopy) to reveal spatial partitioning of protein interactions in relation to specification of cell fate. We show that, in Arabidopsis roots, three fully functional fluorescently tagged cell fate regulators establish cell-type-specific interactions at endogenous expression levels and can form higher order complexes. We reveal that cell-type-specific in vivo FRET-FLIM distributions reflect conformational changes of these complexes to differentially regulate target genes and specify distinct cell fates.
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186
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Nicolas WJ, Grison MS, Trépout S, Gaston A, Fouché M, Cordelières FP, Oparka K, Tilsner J, Brocard L, Bayer EM. Architecture and permeability of post-cytokinesis plasmodesmata lacking cytoplasmic sleeves. NATURE PLANTS 2017; 3:17082. [PMID: 28604682 DOI: 10.1038/nplants.2017.82] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 05/08/2017] [Indexed: 05/08/2023]
Abstract
Plasmodesmata are remarkable cellular machines responsible for the controlled exchange of proteins, small RNAs and signalling molecules between cells. They are lined by the plasma membrane (PM), contain a strand of tubular endoplasmic reticulum (ER), and the space between these two membranes is thought to control plasmodesmata permeability. Here, we have reconstructed plasmodesmata three-dimensional (3D) ultrastructure with an unprecedented level of 3D information using electron tomography. We show that within plasmodesmata, ER-PM contact sites undergo substantial remodelling events during cell differentiation. Instead of being open pores, post-cytokinesis plasmodesmata present such intimate ER-PM contact along the entire length of the pores that no intermembrane gap is visible. Later on, during cell expansion, the plasmodesmata pore widens and the two membranes separate, leaving a cytosolic sleeve spanned by tethers whose presence correlates with the appearance of the intermembrane gap. Surprisingly, the post-cytokinesis plasmodesmata allow diffusion of macromolecules despite the apparent lack of an open cytoplasmic sleeve, forcing the reassessment of the mechanisms that control plant cell-cell communication.
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Affiliation(s)
- William J Nicolas
- Laboratory of Membrane Biogenesis, UMR5200 CNRS, University of Bordeaux, 71 Avenue Edouard Bourlaux, 33883 Villenave d'Ornon Cedex, France
| | - Magali S Grison
- Laboratory of Membrane Biogenesis, UMR5200 CNRS, University of Bordeaux, 71 Avenue Edouard Bourlaux, 33883 Villenave d'Ornon Cedex, France
| | - Sylvain Trépout
- Institut Curie, Centre de Recherche, Bât. 112, Centre Universitaire, 91405 Orsay Cedex, France
| | - Amélia Gaston
- Laboratory of Membrane Biogenesis, UMR5200 CNRS, University of Bordeaux, 71 Avenue Edouard Bourlaux, 33883 Villenave d'Ornon Cedex, France
| | - Mathieu Fouché
- Laboratory of Membrane Biogenesis, UMR5200 CNRS, University of Bordeaux, 71 Avenue Edouard Bourlaux, 33883 Villenave d'Ornon Cedex, France
| | - Fabrice P Cordelières
- Bordeaux Imaging Centre, UMS 3420 CNRS, CNRS-INSERM-University of Bordeaux 146, rue Léo Saignat, 33076 Bordeaux Cedex, France
| | - Karl Oparka
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Jens Tilsner
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
- Cell and Molecular Sciences, James Hutton Institute, Dundee DD2 5DA, UK
| | - Lysiane Brocard
- Bordeaux Imaging Centre, Plant Imaging Plateform, UMS 3420, INRA-CNRS-INSERM-University of Bordeaux, 71 Avenue Edouard Bourlaux, 33883 Villenave-d'Ornon Cedex, France
| | - Emmanuelle M Bayer
- Laboratory of Membrane Biogenesis, UMR5200 CNRS, University of Bordeaux, 71 Avenue Edouard Bourlaux, 33883 Villenave d'Ornon Cedex, France
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187
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Choi WG, Miller G, Wallace I, Harper J, Mittler R, Gilroy S. Orchestrating rapid long-distance signaling in plants with Ca 2+ , ROS and electrical signals. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:698-707. [PMID: 28112437 PMCID: PMC5677518 DOI: 10.1111/tpj.13492] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/15/2017] [Accepted: 01/17/2017] [Indexed: 05/18/2023]
Abstract
Plants show a rapid systemic response to a wide range of environmental stresses, where the signals from the site of stimulus perception are transmitted to distal organs to elicit plant-wide responses. A wide range of signaling molecules are trafficked through the plant, but a trio of potentially interacting messengers, reactive oxygen species (ROS), Ca2+ and electrical signaling ('trio signaling') appear to form a network supporting rapid signal transmission. The molecular components underlying this rapid communication are beginning to be identified, such as the ROS producing NAPDH oxidase RBOHD, the ion channel two pore channel 1 (TPC1), and glutamate receptor-like channels GLR3.3 and GLR3.6. The plant cell wall presents a plant-specific route for possible propagation of signals from cell to cell. However, the degree to which the cell wall limits information exchange between cells via transfer of small molecules through an extracellular route, or whether it provides an environment to facilitate transmission of regulators such as ROS or H+ remains to be determined. Similarly, the role of plasmodesmata as both conduits and gatekeepers for the propagation of rapid cell-to-cell signaling remains a key open question. Regardless of how signals move from cell to cell, they help prepare distant parts of the plant for impending challenges from specific biotic or abiotic stresses.
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Affiliation(s)
- Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, University of Nevada, 1664 North Virginia Street, Reno, NV 89557, USA
- For correspondence ( or )
| | - Gad Miller
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, The Gonda Medical Diagnostic Research Building (204), Room 211, Ramat-Gan 52900, Israel
| | - Ian Wallace
- Department of Biochemistry and Molecular Biology, University of Nevada, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Jeffrey Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, 1664 North Virginia Street, Reno, NV 89557, USA
- For correspondence ( or )
| | - Ron Mittler
- Department of Biological Sciences, College of Arts and Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203, USA
| | - Simon Gilroy
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Drive, Madison, WI 53706, USA
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188
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Strigolactone- and Karrikin-Independent SMXL Proteins Are Central Regulators of Phloem Formation. Curr Biol 2017; 27:1241-1247. [PMID: 28392107 PMCID: PMC5405109 DOI: 10.1016/j.cub.2017.03.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/01/2017] [Accepted: 03/08/2017] [Indexed: 11/25/2022]
Abstract
Plant stem cell niches, the meristems, require long-distance transport of energy metabolites and signaling molecules along the phloem tissue. However, currently it is unclear how specification of phloem cells is controlled. Here we show that the genes SUPPRESSOR OF MAX2 1-LIKE3 (SMXL3), SMXL4, and SMXL5 act as cell-autonomous key regulators of phloem formation in Arabidopsis thaliana. The three genes form an uncharacterized subclade of the SMXL gene family that mediates hormonal strigolactone and karrikin signaling. Strigolactones are endogenous signaling molecules regulating shoot and root branching [1] whereas exogenous karrikin molecules induce germination after wildfires [2]. Both activities depend on the F-box protein and SCF (Skp, Cullin, F-box) complex component MORE AXILLARY GROWTH2 (MAX2) [3, 4, 5]. Strigolactone and karrikin perception leads to MAX2-dependent degradation of distinct SMXL protein family members, which is key for mediating hormonal effects [6, 7, 8, 9, 10, 11, 12]. However, the nature of events immediately downstream of SMXL protein degradation and whether all SMXL proteins mediate strigolactone or karrikin signaling is unknown. In this study we demonstrate that, within the SMXL gene family, specifically SMXL3/4/5 deficiency results in strong defects in phloem formation, altered sugar accumulation, and seedling lethality. By comparing protein stabilities, we show that SMXL3/4/5 proteins function differently to canonical strigolactone and karrikin signaling mediators, although being functionally interchangeable with those under low strigolactone/karrikin signaling conditions. Our observations reveal a fundamental mechanism of phloem formation and indicate that diversity of SMXL protein functions is essential for a steady fuelling of plant meristems. SMXL3/4/5 genes act as general promoters of phloem formation SMXL3/4/5 proteins are expressed and function very early during phloem development SMXL3/4/5 proteins do not mediate strigolactone or karrikin signaling Strigolactone/karrkin-dependent SMXL proteins are able to replace SMXL5
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189
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Iswanto ABB, Kim JY. Lipid Raft, Regulator of Plasmodesmal Callose Homeostasis. PLANTS 2017; 6:plants6020015. [PMID: 28368351 PMCID: PMC5489787 DOI: 10.3390/plants6020015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 11/16/2022]
Abstract
Abstract: The specialized plasma membrane microdomains known as lipid rafts are enriched by sterols and sphingolipids. Lipid rafts facilitate cellular signal transduction by controlling the assembly of signaling molecules and membrane protein trafficking. Another specialized compartment of plant cells, the plasmodesmata (PD), which regulates the symplasmic intercellular movement of certain molecules between adjacent cells, also contains a phospholipid bilayer membrane. The dynamic permeability of plasmodesmata (PDs) is highly controlled by plasmodesmata callose (PDC), which is synthesized by callose synthases (CalS) and degraded by β-1,3-glucanases (BGs). In recent studies, remarkable observations regarding the correlation between lipid raft formation and symplasmic intracellular trafficking have been reported, and the PDC has been suggested to be the regulator of the size exclusion limit of PDs. It has been suggested that the alteration of lipid raft substances impairs PDC homeostasis, subsequently affecting PD functions. In this review, we discuss the substantial role of membrane lipid rafts in PDC homeostasis and provide avenues for understanding the fundamental behavior of the lipid raft-processed PDC.
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Affiliation(s)
- Arya Bagus Boedi Iswanto
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
| | - Jae-Yean Kim
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
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190
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Symplastic communication spatially directs local auxin biosynthesis to maintain root stem cell niche in Arabidopsis. Proc Natl Acad Sci U S A 2017; 114:4005-4010. [PMID: 28348232 DOI: 10.1073/pnas.1616387114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Stem cells serve as the source of new cells for plant development. A group of stem cells form a stem cell niche (SCN) at the root tip and in the center of the SCN are slowly dividing cells called the quiescent center (QC). QC is thought to function as a signaling hub that inhibits differentiation of surrounding stem cells. Although it has been generally assumed that cell-to-cell communication provides positional information for QC and SCN maintenance, the tools for testing this hypothesis have long been lacking. Here we exploit a system that effectively blocks plasmodesmata (PD)-mediated signaling to explore how cell-to-cell communication functions in the SCN. We showed that the symplastic signaling between the QC and adjacent cells directs the formation of local auxin maxima and establishment of AP2-domain transcription factors, PLETHORA gradients. Interestingly we found symplastic signaling is essential for local auxin biosynthesis, which acts together with auxin polar transport to provide the guidance for local auxin enrichment. Therefore, we demonstrate the crucial role of cell-to-cell communication in the SCN maintenance and further uncover a mechanism by which symplastic signaling initiates and reinforces the positional information during stem cell maintenance via auxin regulation.
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191
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Pompa A, De Marchis F, Pallotta MT, Benitez-Alfonso Y, Jones A, Schipper K, Moreau K, Žárský V, Di Sansebastiano GP, Bellucci M. Unconventional Transport Routes of Soluble and Membrane Proteins and Their Role in Developmental Biology. Int J Mol Sci 2017; 18:ijms18040703. [PMID: 28346345 PMCID: PMC5412289 DOI: 10.3390/ijms18040703] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 12/30/2022] Open
Abstract
Many proteins and cargoes in eukaryotic cells are secreted through the conventional secretory pathway that brings proteins and membranes from the endoplasmic reticulum to the plasma membrane, passing through various cell compartments, and then the extracellular space. The recent identification of an increasing number of leaderless secreted proteins bypassing the Golgi apparatus unveiled the existence of alternative protein secretion pathways. Moreover, other unconventional routes for secretion of soluble or transmembrane proteins with initial endoplasmic reticulum localization were identified. Furthermore, other proteins normally functioning in conventional membrane traffic or in the biogenesis of unique plant/fungi organelles or in plasmodesmata transport seem to be involved in unconventional secretory pathways. These alternative pathways are functionally related to biotic stress and development, and are becoming more and more important in cell biology studies in yeast, mammalian cells and in plants. The city of Lecce hosted specialists working on mammals, plants and microorganisms for the inaugural meeting on “Unconventional Protein and Membrane Traffic” (UPMT) during 4–7 October 2016. The main aim of the meeting was to include the highest number of topics, summarized in this report, related to the unconventional transport routes of protein and membranes.
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Affiliation(s)
- Andrea Pompa
- Institute of Biosciences and Bioresources-Research Division of Perugia, National Research Council (CNR), via della Madonna Alta 130, 06128 Perugia, Italy.
| | - Francesca De Marchis
- Institute of Biosciences and Bioresources-Research Division of Perugia, National Research Council (CNR), via della Madonna Alta 130, 06128 Perugia, Italy.
| | | | | | - Alexandra Jones
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
| | - Kerstin Schipper
- Institute for Microbiology, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany.
| | - Kevin Moreau
- Clinical Biochemistry, Institute of Metabolic Science, University of Cambridge, Cambridge CB2 1TN, UK.
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844, Prague 2, Czech Republic.
- Institute of Experimental Botany, v.v.i., the Czech Academy of Sciences, 16502, Prague 6, Czech Republic.
| | - Gian Pietro Di Sansebastiano
- Department of Biological and Environmental Sciences and Technologies (DISTEBA), University of Salento, S.P. 6, 73100 Lecce, Italy.
| | - Michele Bellucci
- Institute of Biosciences and Bioresources-Research Division of Perugia, National Research Council (CNR), via della Madonna Alta 130, 06128 Perugia, Italy.
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192
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Raissig MT, Matos JL, Anleu Gil MX, Kornfeld A, Bettadapur A, Abrash E, Allison HR, Badgley G, Vogel JP, Berry JA, Bergmann DC. Mobile MUTE specifies subsidiary cells to build physiologically improved grass stomata. Science 2017; 355:1215-1218. [PMID: 28302860 DOI: 10.1126/science.aal3254] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 02/16/2017] [Indexed: 01/19/2023]
Abstract
Plants optimize carbon assimilation while limiting water loss by adjusting stomatal aperture. In grasses, a developmental innovation-the addition of subsidiary cells (SCs) flanking two dumbbell-shaped guard cells (GCs)-is linked to improved stomatal physiology. Here, we identify a transcription factor necessary and sufficient for SC formation in the wheat relative Brachypodium distachyon. Unexpectedly, the transcription factor is an ortholog of the stomatal regulator AtMUTE, which defines GC precursor fate in Arabidopsis The novel role of BdMUTE in specifying lateral SCs appears linked to its acquisition of cell-to-cell mobility in Brachypodium Physiological analyses on SC-less plants experimentally support classic hypotheses that SCs permit greater stomatal responsiveness and larger range of pore apertures. Manipulation of SC formation and function in crops, therefore, may be an effective approach to enhance plant performance.
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Affiliation(s)
- Michael T Raissig
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA.
| | - Juliana L Matos
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - M Ximena Anleu Gil
- Howard Hughes Medical Institute (HHMI), Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - Ari Kornfeld
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA
| | - Akhila Bettadapur
- Howard Hughes Medical Institute (HHMI), Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - Emily Abrash
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - Hannah R Allison
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - Grayson Badgley
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA
| | - John P Vogel
- U.S. Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598, USA
| | - Joseph A Berry
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA
| | - Dominique C Bergmann
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA. .,Howard Hughes Medical Institute (HHMI), Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
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193
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Ross-Elliott TJ, Jensen KH, Haaning KS, Wager BM, Knoblauch J, Howell AH, Mullendore DL, Monteith AG, Paultre D, Yan D, Otero S, Bourdon M, Sager R, Lee JY, Helariutta Y, Knoblauch M, Oparka KJ. Phloem unloading in Arabidopsis roots is convective and regulated by the phloem-pole pericycle. eLife 2017; 6. [PMID: 28230527 PMCID: PMC5365319 DOI: 10.7554/elife.24125] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 02/17/2017] [Indexed: 02/05/2023] Open
Abstract
In plants, a complex mixture of solutes and macromolecules is transported by the phloem. Here, we examined how solutes and macromolecules are separated when they exit the phloem during the unloading process. We used a combination of approaches (non-invasive imaging, 3D-electron microscopy, and mathematical modelling) to show that phloem unloading of solutes in Arabidopsis roots occurs through plasmodesmata by a combination of mass flow and diffusion (convective phloem unloading). During unloading, solutes and proteins are diverted into the phloem-pole pericycle, a tissue connected to the protophloem by a unique class of ‘funnel plasmodesmata’. While solutes are unloaded without restriction, large proteins are released through funnel plasmodesmata in discrete pulses, a phenomenon we refer to as ‘batch unloading’. Unlike solutes, these proteins remain restricted to the phloem-pole pericycle. Our data demonstrate a major role for the phloem-pole pericycle in regulating phloem unloading in roots. DOI:http://dx.doi.org/10.7554/eLife.24125.001 A mechanism called photosynthesis allows plants to use energy from sunlight to make sugars from carbon dioxide gas and water. These sugars can then be used as fuel, or as building blocks for wood and other plant structures. Every part of the plant requires sugars, but most photosynthesis happens in the leaves and stems, so the sugars need to be able to move around the plant to wherever they are needed. Phloem tubes form a network that transports sugar, proteins and other molecules around the plant within a fluid known as sap. Because this network is so extensive, it is very difficult to study, which has left researchers with major questions about how it works. For example, it is not clear how the sugar and other molecules leave the phloem when they reach their destination. Ross-Elliot et al. used a combination of microscopy and mathematical modeling to investigate how sugars and other molecules leave the phloem in the roots of a plant called Arabidopsis thaliana. The experiments show that these molecules move directly into cells within a neighboring tissue called the phloem-pole pericycle via pores known as funnel plasmodesmata. Ross-Elliot et al. incorporated the experimental data into a mathematical model of phloem unloading. This model suggests that sugars and other small molecules move freely through the funnel plasmodesmata, but large proteins pass through these pores in pulses. Future challenges include finding out exactly how plants control phloem unloading and to investigate whether it is possible to modify the delivery of specific molecules to particular parts of the plant. DOI:http://dx.doi.org/10.7554/eLife.24125.002
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Affiliation(s)
| | - Kaare H Jensen
- Department of Physics, Technical University of Denmark, Lyngby, Denmark
| | - Katrine S Haaning
- Department of Physics, Technical University of Denmark, Lyngby, Denmark
| | - Brittney M Wager
- School of Biological Sciences, Washington State University, Pullman, United States
| | - Jan Knoblauch
- School of Biological Sciences, Washington State University, Pullman, United States
| | - Alexander H Howell
- School of Biological Sciences, Washington State University, Pullman, United States
| | - Daniel L Mullendore
- School of Biological Sciences, Washington State University, Pullman, United States
| | - Alexander G Monteith
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington, Oxford, United Kingdom
| | - Danae Paultre
- Institute of Molecular Plant Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Dawei Yan
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Sofia Otero
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Matthieu Bourdon
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Ross Sager
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, United States
| | - Jung-Youn Lee
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, United States
| | - Ykä Helariutta
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, United States
| | - Karl J Oparka
- Institute of Molecular Plant Science, University of Edinburgh, Edinburgh, United Kingdom
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194
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Ingram GC. Dying to live: cell elimination as a developmental strategy in angiosperm seeds. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:785-796. [PMID: 27702990 DOI: 10.1093/jxb/erw364] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The complete elimination of unwanted cells during development is a repeated theme in both multicellular animals and in plants. In plants, such events have been extensively studied and reviewed in terms of their molecular regulation, of marker genes and proteins expressed, and in terms of cellular changes associated with their progression. This review will take a slightly different view of developmental cell elimination and will concentrate specifically on the numerous elimination events that occur during ovule and seed development (here grouped together as seed development). It asks why this cell elimination occurs in specific seed tissues, in order to understand something about the commonalities underlying how seemingly disparate events are triggered and regulated. Finally, by placing the seed in its broader evolutionary context, the question of why cell elimination may have emerged as such a key component of the seed developmental toolbox will be considered.
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Affiliation(s)
- Gwyneth C Ingram
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, CNRS (UMR 5667), INRA (UMR 0879), UCB Lyon 1, Ecole Normale Supérieure de Lyon, F-69342 Lyon, France
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195
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Klink VP, Sharma K, Pant SR, McNeece B, Niraula P, Lawrence GW. Components of the SNARE-containing regulon are co-regulated in root cells undergoing defense. PLANT SIGNALING & BEHAVIOR 2017; 12:e1274481. [PMID: 28010187 PMCID: PMC5351740 DOI: 10.1080/15592324.2016.1274481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/14/2016] [Accepted: 12/15/2016] [Indexed: 05/23/2023]
Abstract
The term regulon has been coined in the genetic model plant Arabidopsis thaliana, denoting a structural and physiological defense apparatus defined genetically through the identification of the penetration (pen) mutants. The regulon is composed partially by the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) syntaxin PEN1. PEN1 has homology to a Saccharomyces cerevisae gene that regulates a Secretion (Sec) protein, Suppressor of Sec 1 (Sso1p). The regulon is also composed of the β-glucosidase (PEN2) and an ATP binding cassette (ABC) transporter (PEN3). While important in inhibiting pathogen infection, limited observations have been made regarding the transcriptional regulation of regulon genes until now. Experiments made using the model agricultural Glycine max (soybean) have identified co-regulated gene expression of regulon components. The results explain the observation of hundreds of genes expressed specifically in the root cells undergoing the natural process of defense. Data regarding additional G. max genes functioning within the context of the regulon are presented here, including Sec 14, Sec 4 and Sec 23. Other examined G. max homologs of membrane fusion genes include an endosomal bromo domain-containing protein1 (Bro1), syntaxin6 (SYP6), SYP131, SYP71, SYP8, Bet1, coatomer epsilon (ϵ-COP), a coatomer zeta (ζ-COP) paralog and an ER to Golgi component (ERGIC) protein. Furthermore, the effectiveness of biochemical pathways that would function within the context of the regulon ave been examined, including xyloglucan xylosyltransferase (XXT), reticuline oxidase (RO) and galactinol synthase (GS). The experiments have unveiled the importance of the regulon during defense in the root and show how the deposition of callose relates to the process.
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Affiliation(s)
- Vincent P. Klink
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Keshav Sharma
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Shankar R. Pant
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Brant McNeece
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Prakash Niraula
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Gary W. Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS, USA
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196
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Michalko J, Renner T, Mészáros P, Socha P, Moravčíková J, Blehová A, Libantová J, Polóniová Z, Matušíková I. Molecular characterization and evolution of carnivorous sundew (Drosera rotundifolia L.) class V β-1,3-glucanase. PLANTA 2017; 245:77-91. [PMID: 27580619 DOI: 10.1007/s00425-016-2592-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 08/25/2016] [Indexed: 06/06/2023]
Abstract
MAIN CONCLUSION A gene for β-1,3-glucanase was isolated from carnivorous sundew. It is active in leaves and roots, but not in digestive glands. Analyses in transgenic tobacco suggest its function in germination. Ancestral plant β-1,3-glucanases (EC 3.2.1.39) played a role in cell division and cell wall remodelling, but divergent evolution has extended their roles in plant defense against stresses to decomposition of prey in carnivorous plants. As available gene sequences from carnivorous plants are rare, we isolated a glucanase gene from roundleaf sundew (Drosera rotundifolia L.) by a genome walking approach. Computational predictions recognized typical gene features and protein motifs described for other plant β-1,3-glucanases. Phylogenetic reconstructions suggest strong support for evolutionary relatedness to class V β-1,3-glucanases, including homologs that are active in the traps of related carnivorous species. The gene is expressed in sundew vegetative tissues but not in flowers and digestive glands, and encodes for a functional enzyme when expressed in transgenic tobacco. Detailed analyses of the supposed promoter both in silico and in transgenic tobacco suggest that this glucanase plays a role in development. Specific spatiotemporal activity was observed during transgenic seed germination. Later during growth, the sundew promoter was active in marginal and sub-marginal areas of apical true leaf meristems of young tobacco plants. These results suggest that the isolated glucanase gene is regulated endogenously, possibly by auxin. This is the first report on a nuclear gene study from sundew.
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Affiliation(s)
- Jaroslav Michalko
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademická 2, P.O. Box 39A, 950 07, Nitra, Slovak Republic
| | - Tanya Renner
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182-4614, USA
| | - Patrik Mészáros
- Department of Botany and Genetics, Faculty of Natural Sciences, Constantine the Philosopher University, Nábrežie mládeže 91, 949 74, Nitra, Slovak Republic
| | - Peter Socha
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademická 2, P.O. Box 39A, 950 07, Nitra, Slovak Republic
| | - Jana Moravčíková
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademická 2, P.O. Box 39A, 950 07, Nitra, Slovak Republic
| | - Alžbeta Blehová
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University, Mlynská dolina B2, 842 15, Bratislava, Slovak Republic
| | - Jana Libantová
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademická 2, P.O. Box 39A, 950 07, Nitra, Slovak Republic
| | - Zuzana Polóniová
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademická 2, P.O. Box 39A, 950 07, Nitra, Slovak Republic
| | - Ildikó Matušíková
- Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences, Akademická 2, P.O. Box 39A, 950 07, Nitra, Slovak Republic.
- Department of Ecochemistry and Radioecology, University of SS. Cyril and Methodius, J. Herdu 2, 917 01, Trnava, Slovak Republic.
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Ramachandran P, Carlsbecker A, Etchells JP. Class III HD-ZIPs govern vascular cell fate: an HD view on patterning and differentiation. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:55-69. [PMID: 27794018 DOI: 10.1093/jxb/erw370] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plant vasculature is required for the transport of water and solutes throughout the plant body. It is constituted of xylem, specialized for transport of water, and phloem, that transports photosynthates. These two differentiated tissues are specified early in development and arise from divisions in the procambium, which is the vascular meristem during primary growth. During secondary growth, the xylem and phloem are further expanded via differentiation of cells derived from divisions in the cambium. Almost all of the developmental fate decisions in this process, including vascular specification, patterning, and differentiation, are regulated by transcription factors belonging to the class III homeodomain-leucine zipper (HD-ZIP III) family. This review draws together the literature describing the roles that these genes play in vascular development, looking at how HD-ZIP IIIs are regulated, and how they in turn influence other regulators of vascular development. Themes covered vary, from interactions between HD-ZIP IIIs and auxin, cytokinin, and brassinosteroids, to the requirement for exquisite spatial and temporal regulation of HD-ZIP III expression through miRNA-mediated post-transcriptional regulation, and interactions with other transcription factors. The literature described places the HD-ZIP III family at the centre of a complex network required for initiating and maintaining plant vascular tissues.
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Affiliation(s)
- Prashanth Ramachandran
- Physiological Botany, Department of Organismal Biology and Linnean Centre for Plant Biology in Uppsala, Uppsala University, Ulls väg 24E, SE-756 51 Uppsala, Sweden
| | - Annelie Carlsbecker
- Physiological Botany, Department of Organismal Biology and Linnean Centre for Plant Biology in Uppsala, Uppsala University, Ulls väg 24E, SE-756 51 Uppsala, Sweden
| | - J Peter Etchells
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
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198
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Majumdar R, Rajasekaran K, Cary JW. RNA Interference (RNAi) as a Potential Tool for Control of Mycotoxin Contamination in Crop Plants: Concepts and Considerations. FRONTIERS IN PLANT SCIENCE 2017; 8:200. [PMID: 28261252 PMCID: PMC5306134 DOI: 10.3389/fpls.2017.00200] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/02/2017] [Indexed: 05/20/2023]
Abstract
Mycotoxin contamination in food and feed crops is a major concern worldwide. Fungal pathogens of the genera Aspergillus. Fusarium, and Penicillium are a major threat to food and feed crops due to production of mycotoxins such as aflatoxins, 4-deoxynivalenol, patulin, and numerous other toxic secondary metabolites that substantially reduce the value of the crop. While host resistance genes are frequently used to introgress disease resistance into elite germplasm, either through traditional breeding or transgenic approaches, such resistance is often compromised by the evolving pathogen over time. RNAi-based host-induced gene silencing of key genes required by the pathogen for optimal growth, virulence and/or toxin production, can serve as an alternative, pre-harvest approach for disease control. RNAi represents a robust and efficient tool that can be used in a highly targeted, tissue specific manner to combat mycotoxigenic fungi infecting crop plants. Successful transgenic RNAi implementation depends on several factors including (1) designing vectors to produce double-stranded RNAs (dsRNAs) that will generate small interfering RNA (siRNA) species for optimal gene silencing and reduced potential for off-target effects; (2) availability of ample target siRNAs at the infection site; (3) efficient uptake of siRNAs by the fungus; (4) siRNA half-life and (5) amplification of the silencing effect. This review provides a critical and comprehensive evaluation of the published literature on the use of RNAi-based approaches to control mycotoxin contamination in crop plants. It also examines experimental strategies used to better understand the mode of action of RNAi with the aim of eliminating mycotoxin contamination, thereby improving food and feed safety.
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199
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Song L, Wang R, Zhang L, Wang Y, Yao S. CRR1 encoding callose synthase functions in ovary expansion by affecting vascular cell patterning in rice. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:620-632. [PMID: 27464824 DOI: 10.1111/tpj.13287] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 07/19/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
The ovary of rice undergoes rapid expansion immediately after fertilization, and this process determines the final sink strength potential of caryopses. To date, work on rice grain development has mainly focused on endosperm filling, whereas information on the essential elements for ovary expansion remains limited. We report here a functional analysis of the ovary expansion retarded mutant crr1 in rice. Map-based cloning revealed that CRR1 encodes a protein homologous to the Arabidopsis callose synthases AtGSL8 and AtGSL10. Point mutation in crr1 resulted in alternative splicing, which led to the formation of the truncated crr1 protein without the β-glucan synthase domain. Iodine staining showed that there were few starch granules and these were unevenly distributed in the pericarp of crr1, and a 5,6-carboxyfluorescein diacetate transport assay revealed that carbohydrates were less efficiently unloaded from the lateral vasculature into the developing caryopsis. CRR1 transcripts were detected in all plant organs, with the highest level found in receptacles, which are mainly composed of vascular tissues. Analysis of pCRR1::GUS transgenic plants showed that CRR1 was specifically expressed in vascular bundle cells. Consistently, loss of function of CRR1 led to disordered patterns of vascular cells in the ovaries and receptacles of the mutant. Furthermore, a small portion of cells in the vascular bundles of crr1 showed defective cell wall formation, and callose deposition was specifically reduced at the plasmodesmata (PD) of cells with aberrant walls. Our results suggest that CRR1 performs a pivotal role in determining initial ovary expansion in rice, possibly via the PD-mediated permeability of cell fate determinants for vascular cell differentiation.
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Affiliation(s)
- Longzhen Song
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ruci Wang
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Li Zhang
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yueming Wang
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Shanguo Yao
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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DNA-dependent homodimerization, sub-cellular partitioning, and protein destabilization control WUSCHEL levels and spatial patterning. Proc Natl Acad Sci U S A 2016; 113:E6307-E6315. [PMID: 27671631 DOI: 10.1073/pnas.1607673113] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The homeodomain transcription factor WUSCHEL (WUS) promotes stem cell maintenance in inflorescence meristems of Arabidopsis thaliana WUS, which is synthesized in the rib meristem, migrates and accumulates at lower levels in adjacent cells. Maintenance of WUS protein levels and spatial patterning distribution is not well-understood. Here, we show that the last 63-aa stretch of WUS is necessary for maintaining different levels of WUS protein in the rib meristem and adjacent cells. The 63-aa region contains the following transcriptional regulatory domains: the acidic region, the WUS-box, which is conserved in WUS-related HOMEOBOX family members, and the ethylene-responsive element binding factor-associated amphiphilic repression (EAR-like) domain. Our analysis reveals that the opposing functions of WUS-box, which is required for nuclear retention, and EAR-like domain, which participates in nuclear export, are necessary to maintain higher nuclear levels of WUS in cells of the rib meristem and lower nuclear levels in adjacent cells. We also show that the N-terminal DNA binding domain, which is required for both DNA binding and homodimerization, along with the homodimerization sequence located in the central part of the protein, restricts WUS from spreading excessively and show that the homodimerization is critical for WUS function. Our analysis also reveals that a higher level of WUS outside the rib meristem leads to protein destabilization, suggesting a new tier of regulation in WUS protein regulation. Taken together our data show that processes that influence WUS protein levels and spatial distribution are highly coupled to its transcriptional activity.
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