51
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Yang W, Ren S, Zhang X, Gao M, Ye S, Qi Y, Zheng Y, Wang J, Zeng L, Li Q, Huang S, He Z. BENT UPPERMOST INTERNODE1 encodes the class II formin FH5 crucial for actin organization and rice development. THE PLANT CELL 2011; 23:661-80. [PMID: 21307285 PMCID: PMC3077787 DOI: 10.1105/tpc.110.081802] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/08/2011] [Accepted: 01/18/2011] [Indexed: 05/18/2023]
Abstract
The actin cytoskeleton is an important regulator of cell expansion and morphogenesis in plants. However, the molecular mechanisms linking the actin cytoskeleton to these processes remain largely unknown. Here, we report the functional analysis of rice (Oryza sativa) FH5/BENT UPPERMOST INTERNODE1 (BUI1), which encodes a formin-type actin nucleation factor and affects cell expansion and plant morphogenesis in rice. The bui1 mutant displayed pleiotropic phenotypes, including bent uppermost internode, dwarfism, wavy panicle rachis, and enhanced gravitropic response. Cytological observation indicated that the growth defects of bui1 were caused mainly by inhibition of cell expansion. Map-based cloning revealed that BUI1 encodes the class II formin FH5. FH5 contains a phosphatase tensin-like domain at its amino terminus and two highly conserved formin-homology domains, FH1 and FH2. In vitro biochemical analyses indicated that FH5 is capable of nucleating actin assembly from free or profilin-bound monomeric actin. FH5 also interacts with the barbed end of actin filaments and prevents the addition and loss of actin subunits from the same end. Interestingly, the FH2 domain of FH5 could bundle actin filaments directly and stabilize actin filaments in vitro. Consistent with these in vitro biochemical activities of FH5/BUI1, the amount of filamentous actin decreased, and the longitudinal actin cables almost disappeared in bui1 cells. The FH2 or FH1FH2 domains of FH5 could also bind to and bundle microtubules in vitro. Thus, our study identified a rice formin protein that regulates de novo actin nucleation and spatial organization of the actin filaments, which are important for proper cell expansion and rice morphogenesis.
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Affiliation(s)
- Weibing Yang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Sulin Ren
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaoming Zhang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Mingjun Gao
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Shenghai Ye
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yongbin Qi
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yiyan Zheng
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Juan Wang
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Longjun Zeng
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Qun Li
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Shanjin Huang
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zuhua He
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- Address correspondence to
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52
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Shi L, Wang B, Gong W, Zhang Y, Zhu L, Yang X. Actin filaments and microtubules of Arabidopsis suspension cells show different responses to changing turgor pressure. Biochem Biophys Res Commun 2011; 405:632-7. [PMID: 21277286 DOI: 10.1016/j.bbrc.2011.01.081] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 01/22/2011] [Indexed: 11/16/2022]
Abstract
Past decades have brought great advances in understanding the relationship between turgor pressure and plant cell growth. New studies have provided evidence that turgor pressure acts as a stimulus for cell growth, and is also a developmental cue for post-embryonic organogenesis. However, the subcellular mechanisms underlying plant cell turgor pressure sensing remain unclear. Here, using the relatively simple undifferentiated cells from suspension cultures, we report real-time in vivo observations of the reorganization of microtubules and actin microfilaments induced by turgor pressure changes. We found that these two cytoskeletal elements differed in their reorganization patterns. Our results will be useful in the understanding of the relationship between the cytoskeleton, turgor pressure, and stress in plant cell morphogenesis.
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Affiliation(s)
- Lanchun Shi
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, PR China
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53
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Ringli C. Monitoring the outside: cell wall-sensing mechanisms. PLANT PHYSIOLOGY 2010; 153:1445-52. [PMID: 20508141 PMCID: PMC2923904 DOI: 10.1104/pp.110.154518] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 05/23/2010] [Indexed: 05/18/2023]
Affiliation(s)
- Christoph Ringli
- Institute of Plant Biology, University of Zurich, 8008 Zurich, Switzerland.
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54
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Conn S, Gilliham M. Comparative physiology of elemental distributions in plants. ANNALS OF BOTANY 2010; 105:1081-102. [PMID: 20410048 PMCID: PMC2887064 DOI: 10.1093/aob/mcq027] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 11/16/2009] [Accepted: 12/16/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plants contain relatively few cell types, each contributing a specialized role in shaping plant function. With respect to plant nutrition, different cell types accumulate certain elements in varying amounts within their storage vacuole. The role and mechanisms underlying cell-specific distribution of elements in plants is poorly understood. SCOPE The phenomenon of cell-specific elemental accumulation has been briefly reviewed previously, but recent technological advances with the potential to probe mechanisms underlying elemental compartmentation have warranted an updated evaluation. We have taken this opportunity to catalogue many of the studies, and techniques used for, recording cell-specific compartmentation of particular elements. More importantly, we use three case-study elements (Ca, Cd and Na) to highlight the basis of such phenomena in terms of their physiological implications and underpinning mechanisms; we also link such distributions to the expression of known ion or solute transporters. CONCLUSIONS Element accumulation patterns are clearly defined by expression of key ion or solute transporters. Although the location of element accumulation is fairly robust, alterations in expression of certain solute transporters, through genetic modifications or by growth under stress, result in perturbations to these patterns. However, redundancy or induced pleiotropic expression effects may complicate attempts to characterize the pathways that lead to cell-specific elemental distribution. Accumulation of one element often has consequences on the accumulation of others, which seems to be driven largely to maintain vacuolar and cytoplasmic osmolarity and charge balance, and also serves as a detoxification mechanism. Altered cell-specific transcriptomics can be shown, in part, to explain some of this compensation.
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Affiliation(s)
- Simon Conn
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
| | - Matthew Gilliham
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
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55
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White PJ, Brown PH. Plant nutrition for sustainable development and global health. ANNALS OF BOTANY 2010; 105:1073-80. [PMID: 20430785 PMCID: PMC2887071 DOI: 10.1093/aob/mcq085] [Citation(s) in RCA: 378] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 03/19/2010] [Accepted: 03/24/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plants require at least 14 mineral elements for their nutrition. These include the macronutrients nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S) and the micronutrients chlorine (Cl), boron (B), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), nickel (Ni) and molybdenum (Mo). These are generally obtained from the soil. Crop production is often limited by low phytoavailability of essential mineral elements and/or the presence of excessive concentrations of potentially toxic mineral elements, such as sodium (Na), Cl, B, Fe, Mn and aluminium (Al), in the soil solution. SCOPE This article provides the context for a Special Issue of the Annals of Botany on 'Plant Nutrition for Sustainable Development and Global Health'. It provides an introduction to plant mineral nutrition and explains how mineral elements are taken up by roots and distributed within plants. It introduces the concept of the ionome (the elemental composition of a subcellular structure, cell, tissue or organism), and observes that the activities of key transport proteins determine species-specific, tissue and cellular ionomes. It then describes how current research is addressing the problems of mineral toxicities in agricultural soils to provide food security and the optimization of fertilizer applications for economic and environmental sustainability. It concludes with a perspective on how agriculture can produce edible crops that contribute sufficient mineral elements for adequate animal and human nutrition.
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Affiliation(s)
- P J White
- Scottish Crop Research Institute, Invergowrie, Dundee DD25DA, UK.
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56
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Leiber RM, John F, Verhertbruggen Y, Diet A, Knox JP, Ringli C. The TOR pathway modulates the structure of cell walls in Arabidopsis. THE PLANT CELL 2010; 22:1898-908. [PMID: 20530756 PMCID: PMC2910960 DOI: 10.1105/tpc.109.073007] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Revised: 05/12/2010] [Accepted: 05/23/2010] [Indexed: 05/18/2023]
Abstract
Plant cell growth is limited by the extension of cell walls, which requires both the synthesis and rearrangement of cell wall components in a controlled fashion. The target of rapamycin (TOR) pathway is a major regulator of cell growth in eukaryotes, and inhibition of this pathway by rapamycin reduces cell growth. Here, we show that in plants, the TOR pathway affects cell wall structures. LRR-extensin1 (LRX1) of Arabidopsis thaliana is an extracellular protein involved in cell wall formation in root hairs, and lrx1 mutants develop aberrant root hairs. rol5 (for repressor of lrx1) was identified as a suppressor of lrx1. The functionally similar ROL5 homolog in yeast, Ncs6p (needs Cla4 to survive 6), was previously found to affect TOR signaling. Inhibition of TOR signaling by rapamycin led to suppression of the lrx1 mutant phenotype and caused specific changes to galactan/rhamnogalacturonan-I and arabinogalactan protein components of cell walls that were similar to those observed in the rol5 mutant. The ROL5 protein accumulates in mitochondria, a target of the TOR pathway and major source of reactive oxygen species (ROS), and rol5 mutants show an altered response to ROS. This suggests that ROL5 might function as a mitochondrial component of the TOR pathway that influences the plant's response to ROS.
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Affiliation(s)
- Ruth-Maria Leiber
- University of Zürich, Institute of Plant Biology, 8008 Zurich, Switzerland
| | - Florian John
- University of Zürich, Institute of Plant Biology, 8008 Zurich, Switzerland
| | - Yves Verhertbruggen
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Anouck Diet
- University of Zürich, Institute of Plant Biology, 8008 Zurich, Switzerland
| | - J. Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Christoph Ringli
- University of Zürich, Institute of Plant Biology, 8008 Zurich, Switzerland
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57
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Li XR, Wang L, Ruan YL. Developmental and molecular physiological evidence for the role of phosphoenolpyruvate carboxylase in rapid cotton fibre elongation. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:287-95. [PMID: 19815688 PMCID: PMC2791122 DOI: 10.1093/jxb/erp299] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/08/2009] [Accepted: 09/14/2009] [Indexed: 05/07/2023]
Abstract
Cotton fibres are hair-like single-cells that elongate to several centimetres long after their initiation from the ovule epidermis at anthesis. The accumulation of malate, along with K+ and sugars, is thought to play an important role in fibre elongation through osmotic regulation and charge balance. However, there is a lack of evidence for or against such an hypothesis. Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme responsible for the synthesis of malate. The potential role of PEPC in cotton fibre elongation is examined here. Developmentally, PEPC activity was higher at the rapid elongation phase than that at the slow elongation stage. Genotypically, PEPC activity correlated positively with the rate of fibre elongation and the final fibre length attained. Importantly, suppression of PEPC activity by LiCl that reduces its phosphorylation status decreased fibre length. To examine the molecular basis underlying PEPC activity, two cDNAs encoding PEPC, GhPEPC1 and 2, were cloned, which represents the major PEPC genes expressed in cotton fibre. RT-PCR analyses revealed that GhPEPC1 and 2 were highly expressed at the rapid elongation phase but weakly at the slow-to-terminal elongation period. In situ hybridization detected mRNA of GhPEPC1 and 2 in 1 d young fibres but not in the ovule epidermis prior to fibre initiation. Collectively, the data indicate that cotton fibre elongation requires high activity of PEPC, probably through the expression of the GhPEPC1 and 2 genes.
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Affiliation(s)
- Xiao-Rong Li
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- Australian–China Research Centre for Crop Improvement, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Lu Wang
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- Australian–China Research Centre for Crop Improvement, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Yong-Ling Ruan
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
- Australian–China Research Centre for Crop Improvement, The University of Newcastle, Callaghan, NSW 2308, Australia
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia
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58
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Kim HK, Verpoorte R. Sample preparation for plant metabolomics. PHYTOCHEMICAL ANALYSIS : PCA 2010; 21:4-13. [PMID: 19904733 DOI: 10.1002/pca.1188] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Sample preparation in plant metabolomics is a fundamental and critical step with important consequences for the accuracy of results. Depending on the analytical tools and the metabolites of interest, sample preparation has to be decided. However, the various methods reported in the literature have many steps in common and consequently the practical considerations concerning the pros and cons are similar. In this review, each step of the sample preparation - harvesting, drying, extraction and purification - will be discussed in detail.
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Affiliation(s)
- Hye Kyong Kim
- Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, PO Box 9502, 2333 CC Leiden, The Netherlands.
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59
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Gierlinger N, Luss S, König C, Konnerth J, Eder M, Fratzl P. Cellulose microfibril orientation of Picea abies and its variability at the micron-level determined by Raman imaging. JOURNAL OF EXPERIMENTAL BOTANY 2009; 61:587-95. [PMID: 20007198 PMCID: PMC2803219 DOI: 10.1093/jxb/erp325] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 10/21/2009] [Accepted: 10/21/2009] [Indexed: 05/18/2023]
Abstract
The functional characteristics of plant cell walls depend on the composition of the cell wall polymers, as well as on their highly ordered architecture at scales from a few nanometres to several microns. Raman spectra of wood acquired with linear polarized laser light include information about polymer composition as well as the alignment of cellulose microfibrils with respect to the fibre axis (microfibril angle). By changing the laser polarization direction in 3 degrees steps, the dependency between cellulose and laser orientation direction was investigated. Orientation-dependent changes of band height ratios and spectra were described by quadratic linear regression and partial least square regressions, respectively. Using the models and regressions with high coefficients of determination (R(2) > 0.99) microfibril orientation was predicted in the S1 and S2 layers distinguished by the Raman imaging approach in cross-sections of spruce normal, opposite, and compression wood. The determined microfibril angle (MFA) in the different S2 layers ranged from 0 degrees to 49.9 degrees and was in coincidence with X-ray diffraction determination. With the prerequisite of geometric sample and laser alignment, exact MFA prediction can complete the picture of the chemical cell wall design gained by the Raman imaging approach at the micron level in all plant tissues.
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Affiliation(s)
- Notburga Gierlinger
- Johannes Kepler University Linz, Institute of Polymer Science, Altenberger Straße 69, 4040 Linz, Austria
| | - Saskia Luss
- Max-Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - Christian König
- Max-Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - Johannes Konnerth
- Institute of Wood Science and Technology, Department of Material Sciences and Process Engineering, BOKU-University of Natural Resources and Applied Life Sciences, Vienna, Austria
| | - Michaela Eder
- Max-Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - Peter Fratzl
- Max-Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
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60
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Moco S, Schneider B, Vervoort J. Plant Micrometabolomics: The Analysis of Endogenous Metabolites Present in a Plant Cell or Tissue. J Proteome Res 2009; 8:1694-703. [DOI: 10.1021/pr800973r] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Sofia Moco
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, and Max-Planck-Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
| | - Bernd Schneider
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, and Max-Planck-Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
| | - Jacques Vervoort
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, and Max-Planck-Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
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61
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Guan YF, Huang XY, Zhu J, Gao JF, Zhang HX, Yang ZN. RUPTURED POLLEN GRAIN1, a member of the MtN3/saliva gene family, is crucial for exine pattern formation and cell integrity of microspores in Arabidopsis. PLANT PHYSIOLOGY 2008; 147:852-63. [PMID: 18434608 PMCID: PMC2409014 DOI: 10.1104/pp.108.118026] [Citation(s) in RCA: 201] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 04/16/2008] [Indexed: 05/18/2023]
Abstract
During microsporogenesis, the microsporocyte (or microspore) plasma membrane plays multiple roles in pollen wall development, including callose secretion, primexine deposition, and exine pattern determination. However, plasma membrane proteins that participate in these processes are still not well known. Here, we report that a new gene, RUPTURED POLLEN GRAIN1 (RPG1), encodes a plasma membrane protein and is required for exine pattern formation of microspores in Arabidopsis (Arabidopsis thaliana). The rpg1 mutant exhibits severely reduced male fertility with an otherwise normal phenotype, which is largely due to the postmeiotic abortion of microspores. Scanning electron microscopy examination showed that exine pattern formation in the mutant is impaired, as sporopollenin is randomly deposited on the pollen surface. Transmission electron microscopy examination further revealed that the primexine formation of mutant microspores is aberrant at the tetrad stage, which leads to defective sporopollenin deposition on microspores and the locule wall. In addition, microspore rupture and cytoplasmic leakage were evident in the rpg1 mutant, which indicates impaired cell integrity of the mutant microspores. RPG1 encodes an MtN3/saliva family protein that is integral to the plasma membrane. In situ hybridization analysis revealed that RPG1 is strongly expressed in microsporocyte (or microspores) and tapetum during male meiosis. The possible role of RPG1 in microsporogenesis is discussed.
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Affiliation(s)
- Yue-Feng Guan
- National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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62
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Ringli C, Bigler L, Kuhn BM, Leiber RM, Diet A, Santelia D, Frey B, Pollmann S, Klein M. The modified flavonol glycosylation profile in the Arabidopsis rol1 mutants results in alterations in plant growth and cell shape formation. THE PLANT CELL 2008; 20:1470-81. [PMID: 18567791 PMCID: PMC2483361 DOI: 10.1105/tpc.107.053249] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 06/02/2008] [Accepted: 06/05/2008] [Indexed: 05/18/2023]
Abstract
Flavonoids are secondary metabolites known to modulate plant growth and development. A primary function of flavonols, a subgroup of flavonoids, is thought to be the modification of auxin fluxes in the plant. Flavonols in the cell are glycosylated, and the repressor of lrx1 (rol1) mutants of Arabidopsis thaliana, affected in rhamnose biosynthesis, have a modified flavonol glycosylation profile. A detailed analysis of the rol1-2 allele revealed hyponastic growth, aberrant pavement cell and stomatal morphology in cotyledons, and defective trichome formation. Blocking flavonoid biosynthesis suppresses the rol1-2 shoot phenotype, suggesting that it is induced by the modified flavonol profile. The hyponastic cotyledons of rol1-2 are likely to be the result of a flavonol-induced increase in auxin concentration. By contrast, the pavement cell, stomata, and trichome formation phenotypes appear not to be induced by the modified auxin distribution. Together, these results suggest that changes in the composition of flavonols can have a tremendous impact on plant development through both auxin-induced and auxin-independent processes.
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Affiliation(s)
- Christoph Ringli
- Institute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland.
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63
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Ruan YL. Rapid cell expansion and cellulose synthesis regulated by plasmodesmata and sugar: insights from the single-celled cotton fibre. FUNCTIONAL PLANT BIOLOGY : FPB 2007; 34:1-10. [PMID: 32689326 DOI: 10.1071/fp06234] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Accepted: 11/21/2006] [Indexed: 05/24/2023]
Abstract
Higher plants comprise mixtures of some 40 different cell types, and this often complicates the interpretation of data obtained at the tissue level. Studies for a given cell type may provide novel insights into the mechanisms underlying defined cellular and developmental processes. In this regard, the cotton fibre represents an excellent single-cell model to study the control of rapid cell elongation and cellulose synthesis. These single cells, initiated from the ovule epidermis at anthesis, typically elongate to ~3-5 cm in the tetraploid species before they switch to intensive secondary cell wall cellulose synthesis. By maturity, more than 94% of fibre weight is cellulose. To unravel the mechanisms of fibre elongation and cellulose synthesis, two hypotheses have been examined: (a) that sucrose degradation and utilisation mediated by sucrose synthase (Sus) may play roles in fibre development and (b) that symplastic isolation of the fibre cells may be required for their rapid elongation. Reverse genetic and biochemical analyses have revealed the critical role that Sus plays in fibre initiation and early elongation. Late in development, plasma-membrane and cell wall association of Sus protein seems to be involved in rapid cellulose synthesis. Cell biology and gene expression studies showed a temporary closure of fibre plasmodesmata (PD), probably due to the deposition of callose, at the rapid phase of elongation. The duration of the PD closure correlates positively with the final fibre length attained. These data support the view that PD closure may be required for fibres to achieve extended elongation. The branching of PD towards the secondary cell wall stage is postulated to function as a molecule sieve for tight control of macromolecule trafficking into fibres to sustain intensive cellulose synthesis.
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Affiliation(s)
- Yong-Ling Ruan
- CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.Email
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64
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Sardar HS, Showalter AM. A Cellular Networking Model Involving Interactions Among Glycosyl-Phosphatidylinositol (GPI)-Anchored Plasma Membrane Arabinogalactan Proteins (AGPs), Microtubules and F-actin in Tobacco BY-2 Cells. PLANT SIGNALING & BEHAVIOR 2007; 2:8-9. [PMID: 19704796 PMCID: PMC2633886 DOI: 10.4161/psb.2.1.3599] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 11/14/2006] [Indexed: 05/28/2023]
Abstract
Arabinogalactan-proteins (AGPs) are perhaps the most abundantly expressed set of proteins at the plant cell surface and play probable roles in cellular architecture and signaling. Although considerable progress has been made to understand the role of AGPs in plant growth and development, their exact functional roles and the molecular mechanisms underlying their interactions with either intra- or extra-cellular molecules are unknown. These unknown interactions were addressed in a recent research article in Plant Physiology. This study reported molecular interactions between AGPs and the cytoskeleton [microtubules, (MTs) and F-actin] in tobacco BY-2 cells. Here in this addendum, a summary of this recent publication and additional perspectives are presented. As reported, perturbation studies were conducted in tobacco BY-2 cells to analyze the effects of an AGP inhibitor (beta-Yariv reagent) on the organization of microtubules [labeled by GFP-MBD (green fluorescent protein-microtubule binding domain)] and F-actin (labeled by rhodamine-phalloidin) and conversely to analyze the effects of a microtubule inhibitor (amiprophosmethyl) and an F-actin inhibitor (cytochalasin-D) on the localization of GPI-anchored GFP-LeAGP-1. These studies implicate a role for GPI-anchored LeAGP-1 in mediating a cell wall-plasma membrane-cytoskeleton connection.
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Affiliation(s)
- Harjinder Singh Sardar
- Department of Environmental and Plant Biology and Molecular and Cellular Biology Program; Ohio University; Athens, Ohio USA
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65
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Zhou J, Wang B, Zhu L, Li Y, Wang Y. A system for studying the effect of mechanical stress on the elongation behavior of immobilized plant cells. Colloids Surf B Biointerfaces 2006; 49:165-74. [PMID: 16632335 DOI: 10.1016/j.colsurfb.2006.03.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Accepted: 03/06/2006] [Indexed: 10/24/2022]
Abstract
The ability to apply controllable mechanical compressive force is essential for the study of plant cells responses to environmental stimulations. The work presented here aims towards establishing a system, which consists of a fabricated apparatus (including a loading unit, displacement sensor, data collector and processor, and a feedback control) and a protocol for test specimen preparation and force loading. By using a force-feedback control circuit coupled to a microchip, delivering the pre-defined and actual controlled stimulus is achieved. To calibrate the apparatus, the corresponding voltages are compared to the known weights. A linear regression is fit to the experimental data and a standardized coefficient of 0.998 is calculated. The morphological changes in response to mechanical stresses were investigated in agarose gel embedded chrysanthemum protoplasts, which tended to be elongated with a preferential axis oriented perpendicularly to the compressive stress direction. The results also indicated that there existed a certain dose-dependent relationship between the intensity of compressive force and the stress-induced responses. Additionally, the elongation response with preferential orientation was inhibited by application of RGD peptides, and its inverted sequence, DGR peptides failed to antagonize the effect of mechanical force on elongation performance.
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Affiliation(s)
- Jing Zhou
- Key Lab for Biomechanics and Tissue Engineering under the State Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, PR China
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66
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Harries PA, Pan A, Quatrano RS. Actin-related protein2/3 complex component ARPC1 is required for proper cell morphogenesis and polarized cell growth in Physcomitrella patens. THE PLANT CELL 2005; 17:2327-39. [PMID: 16006580 PMCID: PMC1182492 DOI: 10.1105/tpc.105.033266] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 05/25/2005] [Accepted: 06/22/2005] [Indexed: 05/03/2023]
Abstract
The actin-related protein2/3 (Arp2/3) complex functions as a regulator of actin filament dynamics in a wide array of eukaryotic cells. Here, we focus on the role of the Arp2/3 complex subunit ARPC1 in elongating tip cells of protonemal filaments of the moss Physcomitrella patens. Using RNA interference (RNAi) to generate loss-of-function mutants, we show dramatic defects in cell morphology manifested as short, irregularly shaped cells with abnormal division patterns. The arpc1 RNAi plants lack the rapidly elongating caulonemal cell type found in wild-type protonemal tissue. The absence of this cell type prevents normal bud formation even in response to cytokinin treatment and results in filamentous colonies lacking leafy gametophores. In addition, arpc1 protoplasts show an increased sensitivity to osmotic shock and are defective in their ability to properly establish a polarized outgrowth during regeneration from a single cell. This failure of arpc1 protoplasts to undergo proper tip growth is rescued by ARPC1 overexpression and is phenocopied in wild-type protoplasts treated with Latrunculin B, a potent inhibitor of actin polymerization. We show in moss that ARPC1, and by inference the Arp2/3 complex, plays a critical role in controlling polarized growth and cell division patterning through its regulation of actin dynamics at the cell apex.
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Affiliation(s)
| | | | - Ralph S. Quatrano
- Department of Biology, Washington University, St. Louis, Missouri 63130-4899
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Fusconi A, Lingua G, Trotta A, Berta G. Effects of arbuscular mycorrhizal colonization and phosphorus application on nuclear ploidy in Allium porrum plants. MYCORRHIZA 2005; 15:313-321. [PMID: 15565274 DOI: 10.1007/s00572-004-0338-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Accepted: 10/15/2004] [Indexed: 05/24/2023]
Abstract
Arbuscular mycorrhizal (AM) colonization can strongly affect the plant cell nucleus, causing displacement from the periphery to the center of the cell, hypertrophy and polyploidization. The hypertrophy response has been shown in a variety of AM plants whilst polyploidization has been reported only in Lycopersicon esculentum, a multiploid species with a small genome. In order to determine whether polyploidization is a general plant response to AM colonization, analyses were performed on Allium porrum, a plant with a large genome, which is much less subject to polyploidization than L. esculentum. The ploidy status of leaves, complete root systems and four zones of the adventitious roots was investigated in relation to phosphorus content, AM colonization and root differentiation in A. porrum plants grown under two different regimes of phosphate nutrition in order to distinguish direct effects of the fungus from those of improved nutrition. Results showed the presence of two nuclear populations (2C and 4C) in all treatments and samples. Linear regression analyses suggested a general negative correlation between phosphorus content and the proportion of 2C nuclei. The percentage of 2C nuclei (and consequently that of 4C nuclei), was also influenced by AM colonization, differentiation and ageing of the root cells, which resulted in earlier occurrence, in time and space, of polyploid nuclei.
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Affiliation(s)
- Anna Fusconi
- Dipartimento di Biologia Vegetale, Università di Torino, Viale Mattioli 25, 10125 Torino, Italy.
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Vissenberg K, Oyama M, Osato Y, Yokoyama R, Verbelen JP, Nishitani K. Differential Expression of AtXTH17, AtXTH18, AtXTH19 and AtXTH20 Genes in Arabidopsis Roots. Physiological Roles in Specification in Cell Wall Construction. ACTA ACUST UNITED AC 2005; 46:192-200. [PMID: 15659443 DOI: 10.1093/pcp/pci013] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Xyloglucan endotransglucosylase/hydrolases (XTHs) are a class of enzymes that are capable of splitting and reconnecting xyloglucan molecules, and are implicated in the construction and restructuring of the cellulose/xyloglucan framework. Thirty-three members of the XTH gene family are found in the genome of Arabidopsis thaliana, but their roles remain unclear. Here, we describe the tissue-specific and growth stage-dependent expression profiles of promoter::GUS fusion constructs for four Arabidopsis XTH genes, AtXTH17, AtXTH18, AtXTH19 and AtXTH20, which are phylogenetically closely related to one another. AtXTH17 and AtXTH18 were expressed in all cell types in the elongating and differentiating region of the root, while AtXTH19 was expressed in the apical dividing and elongating regions, as well as in the differentiation zone, and was up-regulated by auxin. In contrast, AtXTH20 was expressed specifically in vascular tissues in the basal mature region of the root. This expression analysis also disclosed cis-regulatory sequences that are conserved among the four genes, and are responsible for the root-specific expression profile. These results indicate that the four XTH genes, which were generated by gene duplication, have diversified their expression profile within the root in such a way as to take responsibility for particular physiological roles in the cell wall dynamics.
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Affiliation(s)
- Kris Vissenberg
- University of Antwerp, Department of Biology, Plant Physiology and Morphology, Universiteitsplein 1, B-2610 Wilrijk, Belgium
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69
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Ruan YL, Xu SM, White R, Furbank RT. Genotypic and developmental evidence for the role of plasmodesmatal regulation in cotton fiber elongation mediated by callose turnover. PLANT PHYSIOLOGY 2004; 136:4104-13. [PMID: 15557097 PMCID: PMC535841 DOI: 10.1104/pp.104.051540] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 09/27/2004] [Accepted: 09/28/2004] [Indexed: 05/18/2023]
Abstract
Cotton fibers are single-celled hairs that elongate to several centimeters long from the seed coat epidermis of the tetraploid species (Gossypium hirsutum and Gossypium barbadense). Thus, cotton fiber is a unique system to study the mechanisms of rapid cell expansion. Previous work has shown a transient closure of plasmodesmata during fiber elongation (Y.-L. Ruan, D.J. Llewellyn, R.T. Furbank [2001] Plant Cell 13: 47-60). To examine the importance of this closure in fiber elongation, we compared the duration of the plasmodesmata closure among different cotton genotypes differing in fiber length. Confocal imaging of the membrane-impermeant fluorescent molecule carboxyfluorescein revealed a genotypic difference in the duration of the plasmodesmata closure that positively correlates with fiber length among three tetraploid genotypes and two diploid progenitors. In all cases, the closure occurred at the rapid phase of elongation. Aniline blue staining and immunolocalization studies showed that callose deposition and degradation at the fiber base correlates with the timing of plasmodesmata closure and reopening, respectively. Northern analyses showed that the expression of a fiber-specific beta-1,3-glucanase gene, GhGluc1, was undetectable when callose was deposited at the fiber base but became evident at the time of callose degradation. Genotypically, the level of GhGluc1 expression was high in the short fiber genotype and weak in the intermediate and long fiber genotypes. The data provide genotypic and developmental evidence that (1) plasmodesmata closure appears to play an important role in elongating cotton fibers, (2) callose deposition and degradation may be involved in the plasmodesmata closure and reopening, respectively, and (3) the expression of GhGluc1 could play a role in this process by degrading callose, thus opening the plasmodesmata.
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Affiliation(s)
- Yong-Ling Ruan
- CSIRO Plant Industry, Canberra, Australian Capital Territory 2601, Australia.
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Kaźmierczak A. Aminooxyacetic acid inhibits antheridiogenesis and development of Anemia phyllitidis gametophytes. PLANT CELL REPORTS 2004; 23:203-210. [PMID: 15480681 DOI: 10.1007/s00299-004-0829-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Revised: 06/01/2004] [Accepted: 06/06/2004] [Indexed: 05/24/2023]
Abstract
Cytomorphological studies of the development of young fern gametophytes (Anemia phyllitidis) have been used to investigate combined effects of gibberellic acid and ethylene on male sex expression. ACC (the key by-product in ethylene biosynthesis pathway) was found to exert a synergetic effect on the gibberellic acid-induced antheridia formation, and this phenomenon could be related with the specific stimulation of cell growth and activity of their differentiation. To complete and verify those observations male sex expression in the fern gametophytes treated with ACC-biosynthesis inhibitor was reinvestigated. Aminooxyacetic acid (AOA) restrained antheridia formation via inhibition of cell divisions. AOA influenced the arrangement and flexibility of cellulose microfibrils in the antheridial zone cells, thus affecting cell expansion. On the other hand, the level of DNA synthesis was not reduced. Transient increase in the number of S-phase cells, followed by the accumulation of G2-phase cells led to the enhancement of cell polyploidization. All these findings correspond with the previous observations and support participation of ethylene in gibberellic acid-induced male sex expression in ferns.
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Affiliation(s)
- Andrzej Kaźmierczak
- Department of Cytophysiology, University of Łódź, Pilarskiego 14, 90231, Poland.
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Yokoyama R, Nishitani K. Genomic basis for cell-wall diversity in plants. A comparative approach to gene families in rice and Arabidopsis. PLANT & CELL PHYSIOLOGY 2004; 45:1111-21. [PMID: 15509833 DOI: 10.1093/pcp/pch151] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Monocotyledons and dicotyledons are distinct, not only in their body plans and developmental patterns, but also in the structural features of their cell walls. The recent completion of the rice (Oryza sativa) genomic sequence and publication of the sequence data, together with the completed database of the Arabidopsis thaliana genome, provide the first opportunity to compare the full complement of cell-wall-related genes from the two distinct classes of flowering plants. We made this comparison by exploiting the fact that Arabidopsis and rice have type I and type II walls, respectively, and therefore represent the two extremes in terms of the structural features of plant cell walls. In this review article, we classify all cell-wall-related genes into 32 gene families, and generate their phylogenetic trees. Using these data, we can phylogenetically compare individual genes of particular interest between Arabidopsis and rice. This comparative genome approach shows that the differences in wall architecture in the two plant groups actually mirror the diversity of the individual gene families involved in the cell-wall dynamics of the respective plant species. This study also identifies putative rice orthologs of genes with well-defined functions in Arabidopsis and other plant species.
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Affiliation(s)
- Ryusuke Yokoyama
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, 980-8578 Japan
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Abstract
In the turgid cells of plants, protists, fungi, and bacteria, walls resist swelling; they also confer shape on the cell. These two functions are not unrelated: cell physiologists have generally agreed that morphogenesis turns on the deformation of existing wall and the deposition of new wall, while turgor pressure produces the work of expansion. In 1990, I summed up consensus in a phrase: "localized compliance with the global force of turgor pressure." My purpose here is to survey the impact of recent discoveries on the traditional conceptual framework. Topics include the recognition of a cytoskeleton in bacteria; the tide of information and insight about budding in yeast; the role of the Spitzenkörper in hyphal extension; calcium ions and actin dynamics in shaping a tip; and the interplay of protons, expansins and cellulose fibrils in cells of higher plants.
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Affiliation(s)
- Franklin M Harold
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
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