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Zhang X, Rogowski A, Zhao L, Hahn MG, Avci U, Knox JP, Gilbert HJ. Understanding how the complex molecular architecture of mannan-degrading hydrolases contributes to plant cell wall degradation. J Biol Chem 2014; 289:2002-12. [PMID: 24297170 PMCID: PMC3900950 DOI: 10.1074/jbc.m113.527770] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/25/2013] [Indexed: 12/16/2022] Open
Abstract
Microbial degradation of plant cell walls is a central component of the carbon cycle and is of increasing importance in environmentally significant industries. Plant cell wall-degrading enzymes have a complex molecular architecture consisting of catalytic modules and, frequently, multiple non-catalytic carbohydrate binding modules (CBMs). It is currently unclear whether the specificities of the CBMs or the topology of the catalytic modules are the primary drivers for the specificity of these enzymes against plant cell walls. Here, we have evaluated the relationship between CBM specificity and their capacity to enhance the activity of GH5 and GH26 mannanases and CE2 esterases against intact plant cell walls. The data show that cellulose and mannan binding CBMs have the greatest impact on the removal of mannan from tobacco and Physcomitrella cell walls, respectively. Although the action of the GH5 mannanase was independent of the context of mannan in tobacco cell walls, a significant proportion of the polysaccharide was inaccessible to the GH26 enzyme. The recalcitrant mannan, however, was fully accessible to the GH26 mannanase appended to a cellulose binding CBM. Although CE2 esterases display similar specificities against acetylated substrates in vitro, only CjCE2C was active against acetylated mannan in Physcomitrella. Appending a mannan binding CBM27 to CjCE2C potentiated its activity against Physcomitrella walls, whereas a xylan binding CBM reduced the capacity of esterases to deacetylate xylan in tobacco walls. This work provides insight into the biological significance for the complex array of hydrolytic enzymes expressed by plant cell wall-degrading microorganisms.
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Affiliation(s)
- Xiaoyang Zhang
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle-upon-Tyne, NE 4HH, United Kingdom
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Artur Rogowski
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle-upon-Tyne, NE 4HH, United Kingdom
| | - Lei Zhao
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Michael G. Hahn
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - Utku Avci
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
| | - J. Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Harry J. Gilbert
- From the Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle-upon-Tyne, NE 4HH, United Kingdom
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, and
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103
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Miart F, Desprez T, Biot E, Morin H, Belcram K, Höfte H, Gonneau M, Vernhettes S. Spatio-temporal analysis of cellulose synthesis during cell plate formation in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:71-84. [PMID: 24147885 DOI: 10.1111/tpj.12362] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 10/07/2013] [Accepted: 10/18/2013] [Indexed: 05/18/2023]
Abstract
During cytokinesis a new crosswall is rapidly laid down. This process involves the formation at the cell equator of a tubulo-vesicular membrane network (TVN). This TVN evolves into a tubular network (TN) and a planar fenestrated sheet, which extends at its periphery before fusing to the mother cell wall. The role of cell wall polymers in cell plate assembly is poorly understood. We used specific stains and GFP-labelled cellulose synthases (CESAs) to show that cellulose, as well as three distinct CESAs, accumulated in the cell plate already at the TVN stage. This early presence suggests that cellulose is extruded into the tubular membrane structures of the TVN. Co-localisation studies using GFP-CESAs suggest the delivery of cellulose synthase complexes (CSCs) to the cell plate via phragmoplast-associated vesicles. In the more mature TN part of the cell plate, we observed delivery of GFP-CESA from doughnut-shaped organelles, presumably Golgi bodies. During the conversion of the TN into a planar fenestrated sheet, the GFP-CESA density diminished, whereas GFP-CESA levels remained high in the TVN zone at the periphery of the expanding cell plate. We observed retrieval of GFP-CESA in clathrin-containing structures from the central zone of the cell plate and from the plasma membrane of the mother cell, which may contribute to the recycling of CESAs to the peripheral growth zone of the cell plate. These observations, together with mutant phenotypes of cellulose-deficient mutants and pharmacological experiments, suggest a key role for cellulose synthesis already at early stages of cell plate assembly.
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Affiliation(s)
- Fabien Miart
- INRA, UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, AgroParisTech, RD10, F-78000, Versailles, France
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105
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Book AJ, Yennamalli RM, Takasuka TE, Currie CR, Phillips GN, Fox BG. Evolution of substrate specificity in bacterial AA10 lytic polysaccharide monooxygenases. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:109. [PMID: 25161697 PMCID: PMC4144037 DOI: 10.1186/1754-6834-7-109] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/07/2014] [Indexed: 05/06/2023]
Abstract
BACKGROUND Understanding the diversity of lignocellulose-degrading enzymes in nature will provide insights for the improvement of cellulolytic enzyme cocktails used in the biofuels industry. Two families of enzymes, fungal AA9 and bacterial AA10, have recently been characterized as crystalline cellulose or chitin-cleaving lytic polysaccharide monooxygenases (LPMOs). Here we analyze the sequences, structures, and evolution of LPMOs to understand the factors that may influence substrate specificity both within and between these enzyme families. RESULTS Comparative analysis of sequences, solved structures, and homology models from AA9 and AA10 LPMO families demonstrated that, although these two LPMO families are highly conserved, structurally they have minimal sequence similarity outside the active site residues. Phylogenetic analysis of the AA10 family identified clades with putative chitinolytic and cellulolytic activities. Estimation of the rate of synonymous versus non-synonymous substitutions (dN/dS) within two major AA10 subclades showed distinct selective pressures between putative cellulolytic genes (subclade A) and CBP21-like chitinolytic genes (subclade D). Estimation of site-specific selection demonstrated that changes in the active sites were strongly negatively selected in all subclades. Furthermore, all codons in the subclade D had dN/dS values of less than 0.7, whereas codons in the cellulolytic subclade had dN/dS values of greater than 1.5. Positively selected codons were enriched at sites localized on the surface of the protein adjacent to the active site. CONCLUSIONS The structural similarity but absence of significant sequence similarity between AA9 and AA10 families suggests that these enzyme families share an ancient ancestral protein. Combined analysis of amino acid sites under Darwinian selection and structural homology modeling identified a subclade of AA10 with diversifying selection at different surfaces, potentially used for cellulose-binding and protein-protein interactions. Together, these data indicate that AA10 LPMOs are under selection to change their function, which may optimize cellulolytic activity. This work provides a phylogenetic basis for identifying and classifying additional cellulolytic or chitinolytic LPMOs.
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Affiliation(s)
- Adam J Book
- />Department of Energy, Great Lakes Bioenergy Research Center, Madison, 1552 University Avenue, Madison, WI 53726 USA
- />Department of Bacteriology, University of Wisconsin-Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706 USA
| | - Ragothaman M Yennamalli
- />Department of Biochemistry, University of Wisconsin-Madison, Biochemistry Addition, 433 Babcock Dr., Madison, WI 53706 USA
- />Biosciences at Rice, Rice University, George R. Brown Hall, Houston, TX 77005 USA
| | - Taichi E Takasuka
- />Department of Energy, Great Lakes Bioenergy Research Center, Madison, 1552 University Avenue, Madison, WI 53726 USA
- />Department of Biochemistry, University of Wisconsin-Madison, Biochemistry Addition, 433 Babcock Dr., Madison, WI 53706 USA
| | - Cameron R Currie
- />Department of Energy, Great Lakes Bioenergy Research Center, Madison, 1552 University Avenue, Madison, WI 53726 USA
- />Department of Bacteriology, University of Wisconsin-Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706 USA
| | - George N Phillips
- />Department of Energy, Great Lakes Bioenergy Research Center, Madison, 1552 University Avenue, Madison, WI 53726 USA
- />Department of Biochemistry, University of Wisconsin-Madison, Biochemistry Addition, 433 Babcock Dr., Madison, WI 53706 USA
- />Biosciences at Rice, Rice University, George R. Brown Hall, Houston, TX 77005 USA
| | - Brian G Fox
- />Department of Energy, Great Lakes Bioenergy Research Center, Madison, 1552 University Avenue, Madison, WI 53726 USA
- />Department of Biochemistry, University of Wisconsin-Madison, Biochemistry Addition, 433 Babcock Dr., Madison, WI 53706 USA
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Yamazawa A, Iikura T, Morioka Y, Shino A, Ogata Y, Date Y, Kikuchi J. Cellulose digestion and metabolism induced biocatalytic transitions in anaerobic microbial ecosystems. Metabolites 2013; 4:36-52. [PMID: 24958386 PMCID: PMC4018678 DOI: 10.3390/metabo4010036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/18/2013] [Accepted: 12/20/2013] [Indexed: 01/07/2023] Open
Abstract
Anaerobic digestion of highly polymerized biomass by microbial communities present in diverse microbial ecosystems is an indispensable metabolic process for biogeochemical cycling in nature and for industrial activities required to maintain a sustainable society. Therefore, the evaluation of the complicated microbial metabolomics presents a significant challenge. We here describe a comprehensive strategy for characterizing the degradation of highly crystallized bacterial cellulose (BC) that is accompanied by metabolite production for identifying the responsible biocatalysts, including microorganisms and their metabolic functions. To this end, we employed two-dimensional solid- and one-dimensional solution-state nuclear magnetic resonance (NMR) profiling combined with a metagenomic approach using stable isotope labeling. The key components of biocatalytic reactions determined using a metagenomic approach were correlated with cellulose degradation and metabolic products. The results indicate that BC degradation was mediated by cellulases that contain carbohydrate-binding modules and that belong to structural type A. The degradation reactions induced the metabolic dynamics of the microbial community and produced organic compounds, such as acetic acid and propionic acid, mainly metabolized by clostridial species. This combinatorial, functional and structural metagenomic approach is useful for the comprehensive characterization of biomass degradation, metabolic dynamics and their key components in diverse ecosystems.
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Affiliation(s)
- Akira Yamazawa
- Research Planning and Management Group, Kajima Technical Research Institute, Kajima Corporation, 2-19-1 Tobitakyu, Chofu, Tokyo 182-0036, Japan.
| | - Tomohiro Iikura
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Yusuke Morioka
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Amiu Shino
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Yoshiyuki Ogata
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 599-8531, Japan.
| | - Yasuhiro Date
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Jun Kikuchi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
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107
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Matos DA, Whitney IP, Harrington MJ, Hazen SP. Cell walls and the developmental anatomy of the Brachypodium distachyon stem internode. PLoS One 2013; 8:e80640. [PMID: 24278300 PMCID: PMC3836760 DOI: 10.1371/journal.pone.0080640] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 10/11/2013] [Indexed: 12/30/2022] Open
Abstract
While many aspects of plant cell wall polymer structure are known, their spatial and temporal distribution within the stem are not well understood. Here, we studied vascular system and fiber development, which has implication for both biofuel feedstock conversion efficiency and crop yield. The subject of this study, Brachypodium distachyon, has emerged as a grass model for food and energy crop research. Here, we conducted our investigation using B. distachyon by applying various histological approaches and Fourier transform infrared spectroscopy to the stem internode from three key developmental stages. While vascular bundle size and number did not change over time, the size of the interfascicular region increased dramatically, as did cell wall thickness. We also describe internal stem internode anatomy and demonstrate that lignin deposition continues after crystalline cellulose and xylan accumulation ceases. The vascular bundle anatomy of B. distachyon appears to be highly similar to domesticated grasses. While the arrangement of bundles within the stem is highly variable across grasses, B. distachyon appears to be a suitable model for the rind of large C4 grass crops. A better understanding of growth and various anatomical and cell wall features of B. distachyon will further our understanding of plant biomass accumulation processes.
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Affiliation(s)
- Dominick A. Matos
- Biology Department, University of Massachusetts, Amherst, Massachusetts, United States of America
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Ian P. Whitney
- Biology Department, University of Massachusetts, Amherst, Massachusetts, United States of America
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Michael J. Harrington
- Biology Department, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Samuel P. Hazen
- Biology Department, University of Massachusetts, Amherst, Massachusetts, United States of America
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108
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Reddy AP, Simmons CW, D’haeseleer P, Khudyakov J, Burd H, Hadi M, Simmons BA, Singer SW, Thelen MP, VanderGheynst JS. Discovery of microorganisms and enzymes involved in high-solids decomposition of rice straw using metagenomic analyses. PLoS One 2013; 8:e77985. [PMID: 24205054 PMCID: PMC3808287 DOI: 10.1371/journal.pone.0077985] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/16/2013] [Indexed: 02/01/2023] Open
Abstract
High-solids incubations were performed to enrich for microbial communities and enzymes that decompose rice straw under mesophilic (35°C) and thermophilic (55°C) conditions. Thermophilic enrichments yielded a community that was 7.5 times more metabolically active on rice straw than mesophilic enrichments. Extracted xylanase and endoglucanse activities were also 2.6 and 13.4 times greater, respectively, for thermophilic enrichments. Metagenome sequencing was performed on enriched communities to determine community composition and mine for genes encoding lignocellulolytic enzymes. Proteobacteria were found to dominate the mesophilic community while Actinobacteria were most abundant in the thermophilic community. Analysis of protein family representation in each metagenome indicated that cellobiohydrolases containing carbohydrate binding module 2 (CBM2) were significantly overrepresented in the thermophilic community. Micromonospora, a member of Actinobacteria, primarily housed these genes in the thermophilic community. In light of these findings, Micromonospora and other closely related Actinobacteria genera appear to be promising sources of thermophilic lignocellulolytic enzymes for rice straw deconstruction under high-solids conditions. Furthermore, these discoveries warrant future research to determine if exoglucanases with CBM2 represent thermostable enzymes tolerant to the process conditions expected to be encountered during industrial biofuel production.
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Affiliation(s)
- Amitha P. Reddy
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Biological and Agricultural Engineering, University of California Davis, Davis, California, United States of America
| | - Christopher W. Simmons
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Biological and Agricultural Engineering, University of California Davis, Davis, California, United States of America
- Food Science, University of California Davis, Davis, California, United States of America
| | - Patrik D’haeseleer
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Jane Khudyakov
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Helcio Burd
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Masood Hadi
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Biological and Materials Science Center, Sandia National Laboratories, Livermore, California, United States of America
| | - Blake A. Simmons
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Biological and Materials Science Center, Sandia National Laboratories, Livermore, California, United States of America
| | - Steven W. Singer
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Michael P. Thelen
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Jean S. VanderGheynst
- Joint BioEnergy Institute, Emeryville, California, United States of America
- Biological and Agricultural Engineering, University of California Davis, Davis, California, United States of America
- * E-mail:
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109
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Gilbert HJ, Knox JP, Boraston AB. Advances in understanding the molecular basis of plant cell wall polysaccharide recognition by carbohydrate-binding modules. Curr Opin Struct Biol 2013; 23:669-77. [DOI: 10.1016/j.sbi.2013.05.005] [Citation(s) in RCA: 236] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 05/03/2013] [Accepted: 05/09/2013] [Indexed: 11/25/2022]
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Zhang M, Wang B, Xu B. Measurements of single molecular affinity interactions between carbohydrate-binding modules and crystalline cellulose fibrils. Phys Chem Chem Phys 2013; 15:6508-15. [PMID: 23532050 DOI: 10.1039/c3cp51072g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Combining atomic force microscopy (AFM) recognition imaging and single molecule dynamic force spectroscopy (SMDFS), we studied the single molecule affinity interactions between the carbohydrate-binding module (CBM) and plant cell wall cellulose using the CBM3a (from Clostridium thermocellum) and CBM2a (from Cellvibrio japonicus) functionalized AFM tips. The binding efficiencies of the CBMs to the cellulose were determined by the binding areas on the crystalline cellulose fibrils surface using the recognition imaging. Several dynamic and kinetic parameters, such as the reconstructed free energy change, energy barrier and bond lifetime constant, were also obtained based on the measured single molecule unbinding forces, which are used to illuminate the affinity of the CBMs binding to the natural and single cellulose surface from a totally different aspect. It was found that CBM3a has a little higher binding efficiency and affinity than CBM2a to both natural and extracted cellulose surfaces and both the CBMs have higher affinities to the natural cell wall cellulose compared to the extracted single cellulose. The in-depth understanding of the binding mechanisms of the CBM-cellulose interactions of this study may pave the way for more efficient plant cell wall degradation and eventually facilitate biofuel production.
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Affiliation(s)
- Mengmeng Zhang
- Single Molecule Study Laboratory, College of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, GA 30602, USA
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111
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Qi G, Hu R, Yu L, Chai G, Cao Y, Zuo R, Kong Y, Zhou G. Two poplar cellulose synthase-like D genes, PdCSLD5 and PdCSLD6, are functionally conserved with Arabidopsis CSLD3. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:1267-1276. [PMID: 23746994 DOI: 10.1016/j.jplph.2013.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 04/01/2013] [Accepted: 04/07/2013] [Indexed: 06/02/2023]
Abstract
Root hairs are tip-growing long tubular outgrowths of specialized epidermal cells, and are important for nutrient and water uptake and interaction with the soil microflora. Here we characterized two poplar cellulose synthase-like D (CSLD) genes, PdCSLD5 and PdCSLD6, the most probable orthologs to the Arabidopsis AtCSLD3/KOJAK gene. Both PdCSLD5 and PdCSLD6 are strongly expressed in roots, including in the root hairs. Subcellular localization experiments showed that these two proteins are located not only in the polarized plasma membrane of root hair tips, but also in Golgi apparatus of the root hair and non-hair-forming cells. Overexpression of these two poplar genes in the atcsld3 mutant was able to rescue most of the defects caused by disruption of AtCSLD3, including root hair morphological changes, altered cell wall monosaccharide composition, increased non-crystalline β-1,4-glucan and decreased crystalline cellulose contents. Taken together, our results provide evidence indicating that PdCSLD5 and PdCSLD6 are functionally conserved with AtCSLD3 and support a role for PdCSLD5 and PdCSL6 specifically in crystalline cellulose production in poplar root hair tips. The results presented here also suggest that at least part of the mechanism of root hair formation is conserved between herbaceous and woody plants.
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Affiliation(s)
- Guang Qi
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China
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Maschek D, Goodell B, Jellison J, Lessard M, Militz H. A new approach for the study of the chemical composition of bordered pit membranes: 4Pi and confocal laser scanning microscopy. AMERICAN JOURNAL OF BOTANY 2013; 100:1751-1756. [PMID: 24018857 DOI: 10.3732/ajb.1300004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PREMISE OF THE STUDY Coniferous bordered pits are some of the most unique and fascinating microstructures of the lignified cell wall. The pit membrane consists of a margo and a torus region, hence facilitating both xylary water transport and also limiting air intrusion by pit aspiration. Additionally, bordered pits have been reported to play a decisive role in the control of rapid liquid flow via the shrinkage and swelling of pectin. The study of the nanostructural chemical composition of pit membranes has been difficult with common imaging/chemical techniques, which involve drying and/or coating of the samples. • METHODS Using fluorescent tagging and antibodies specific to pectin, and a His-tagged cellulose-binding module that reacts with crystalline cellulose, in combination with confocal laser scanning microscopy (CLSM) and 4Pi microscopy, we generated three-dimensional images of intact pit membranes. • KEY RESULTS With enhanced resolution in the z-direction of the 4Pi microscope, it was possible to distinguish cellulose in the torus and the margo strands of Pinus strobus. The torus was surrounded by pectin, and a pectin ring was found at the margin of the torus. We also found differences in the structure of the pit membrane between aspirated and unaspirated pits, with a displacement of pectin to form a ring-like structure, the collapse of a void in the interior of the torus, and an apparent change in the chemical structure of cellulosic components, during the aspiration process. • CONCLUSIONS The 4Pi microscope is well suited to scanning pit membranes to discover previously undescribed anatomical features in bordered pits and can provide information on chemical composition when used in combination with appropriate probes.
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Affiliation(s)
- Daniela Maschek
- Georg-August-University of Göttingen, Institute for Wood Biology and Wood Products, Büsgenweg 4, D-37077, Göttingen, Germany
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113
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A single-molecule analysis reveals morphological targets for cellulase synergy. Nat Chem Biol 2013; 9:356-61. [DOI: 10.1038/nchembio.1227] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Accepted: 02/28/2013] [Indexed: 11/08/2022]
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114
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Yang F, Mitra P, Zhang L, Prak L, Verhertbruggen Y, Kim JS, Sun L, Zheng K, Tang K, Auer M, Scheller HV, Loqué D. Engineering secondary cell wall deposition in plants. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:325-35. [PMID: 23140549 PMCID: PMC3644865 DOI: 10.1111/pbi.12016] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/21/2012] [Accepted: 09/25/2012] [Indexed: 05/17/2023]
Abstract
Lignocellulosic biomass was used for thousands of years as animal feed and is now considered a great sugar source for biofuels production. It is composed mostly of secondary cell walls built with polysaccharide polymers that are embedded in lignin to reinforce the cell wall structure and maintain its integrity. Lignin is the primary material responsible for biomass recalcitrance to enzymatic hydrolysis. During plant development, deep reductions of lignin cause growth defects and often correlate with the loss of vessel integrity that adversely affects water and nutrient transport in plants. The work presented here describes a new approach to decrease lignin content while preventing vessel collapse and introduces a new strategy to boost transcription factor expression in native tissues. We used synthetic biology tools in Arabidopsis to rewire the secondary cell network by changing promoter-coding sequence associations. The result was a reduction in lignin and an increase in polysaccharide depositions in fibre cells. The promoter of a key lignin gene, C4H, was replaced by the vessel-specific promoter of transcription factor VND6. This rewired lignin biosynthesis specifically for vessel formation while disconnecting C4H expression from the fibre regulatory network. Secondly, the promoter of the IRX8 gene, secondary cell wall glycosyltransferase, was used to express a new copy of the fibre transcription factor NST1, and as the IRX8 promoter is induced by NST1, this also created an artificial positive feedback loop (APFL). The combination of strategies-lignin rewiring with APFL insertion-enhances polysaccharide deposition in stems without over-lignifying them, resulting in higher sugar yields after enzymatic hydrolysis.
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Affiliation(s)
- Fan Yang
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Prajakta Mitra
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Ling Zhang
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
- FSN Plant Biotechnology R&D Centre, Shanghai Jiaotong UniversityShanghai, China
| | - Lina Prak
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Yves Verhertbruggen
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Jin-Sun Kim
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Lan Sun
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Kejian Zheng
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Kexuan Tang
- FSN Plant Biotechnology R&D Centre, Shanghai Jiaotong UniversityShanghai, China
| | - Manfred Auer
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Henrik V Scheller
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Dominique Loqué
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
- *Correspondence (fax 510 486 4252; email )
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Chebli Y, Pujol L, Shojaeifard A, Brouwer I, van Loon JJWA, Geitmann A. Cell wall assembly and intracellular trafficking in plant cells are directly affected by changes in the magnitude of gravitational acceleration. PLoS One 2013; 8:e58246. [PMID: 23516452 PMCID: PMC3596410 DOI: 10.1371/journal.pone.0058246] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 02/05/2013] [Indexed: 01/17/2023] Open
Abstract
Plants are able to sense the magnitude and direction of gravity. This capacity is thought to reside in selected cell types within the plant body that are equipped with specialized organelles called statoliths. However, most plant cells do not possess statoliths, yet they respond to changes in gravitational acceleration. To understand the effect of gravity on the metabolism and cellular functioning of non-specialized plant cells, we investigated a rapidly growing plant cell devoid of known statoliths and without gravitropic behavior, the pollen tube. The effects of hyper-gravity and omnidirectional exposure to gravity on intracellular trafficking and on cell wall assembly were assessed in Camellia pollen tubes, a model system with highly reproducible growth behavior in vitro. Using an epi-fluorescence microscope mounted on the Large Diameter Centrifuge at the European Space Agency, we were able to demonstrate that vesicular trafficking is reduced under hyper-gravity conditions. Immuno-cytochemistry confirmed that both in hyper and omnidirectional gravity conditions, the characteristic spatial profiles of cellulose and callose distribution in the pollen tube wall were altered, in accordance with a dose-dependent effect on pollen tube diameter. Our findings suggest that in response to gravity induced stress, the pollen tube responds by modifying cell wall assembly to compensate for the altered mechanical load. The effect was reversible within few minutes demonstrating that the pollen tube is able to quickly adapt to changing stress conditions.
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Affiliation(s)
- Youssef Chebli
- Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Lauranne Pujol
- Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Anahid Shojaeifard
- Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, Montréal, Québec, Canada
| | | | - Jack J. W. A. van Loon
- Department of Craniofacial Surgery & Oral Cell Biology, Academisch Centrum Tandheelkunde Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Research Institute MOVE, Amsterdam, The Netherlands
- Life and Physical Sciences Instrumentation and Life Support Section (TEC-MMG), European Space Agency (ESA), Noordwijk, The Netherlands
| | - Anja Geitmann
- Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
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116
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Mollet JC, Leroux C, Dardelle F, Lehner A. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth. PLANTS 2013; 2:107-47. [PMID: 27137369 PMCID: PMC4844286 DOI: 10.3390/plants2010107] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 02/19/2013] [Accepted: 02/19/2013] [Indexed: 01/01/2023]
Abstract
The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.
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Affiliation(s)
- Jean-Claude Mollet
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, Normandy University, University of Rouen, 76821 Mont Saint-Aignan, France.
| | - Christelle Leroux
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, Normandy University, University of Rouen, 76821 Mont Saint-Aignan, France.
| | - Flavien Dardelle
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, Normandy University, University of Rouen, 76821 Mont Saint-Aignan, France.
| | - Arnaud Lehner
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, Normandy University, University of Rouen, 76821 Mont Saint-Aignan, France.
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117
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Kim WC, Ko JH, Kim JY, Kim J, Bae HJ, Han KH. MYB46 directly regulates the gene expression of secondary wall-associated cellulose synthases in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:26-36. [PMID: 26011122 DOI: 10.1111/j.1365-313x.2012.05124.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 08/05/2012] [Accepted: 08/08/2012] [Indexed: 05/21/2023]
Abstract
Cellulose is the most abundant biopolymer on Earth. Three cellulose synthases (CESA4, CESA7 and CESA8) are necessary for cellulose production in the secondary cell walls of Arabidopsis. Little is known about how expression of these CESA genes is regulated. We recently identified a cis-regulatory element (M46RE) that is recognized by MYB46, which is a master switch for secondary wall formation in Arabidopsis. A genome-wide survey of promoter sequences for the presence of M46REs led to the hypothesis that MYB46 may function as a direct regulator of all three secondary wall-associated cellulose synthase genes: CESA4, CESA7 and CESA8. We tested this hypothesis using several lines of experimental evidence. All three CESA genes are highly up-regulated by both constitutive and inducible over-expression of MYB46 in planta. Using a steroid receptor-based inducible activation system, we show that MYB46 directly activates transcription of the three CESA genes. We then used an electrophoretic mobility shift assay and chromatin immunoprecipitation analysis to confirm that MYB46 protein directly binds to the promoters of the three CESA genes both in vitro and in vivo. Furthermore, ectopic up-regulation of MYB46 resulted in a significant increase of crystalline cellulose content in Arabidopsis. Taken together, we have identified MYB46 as a transcription factor that directly regulates all three secondary wall-associated CESA genes. Yeast one-hybrid screening identified additional transcription factors that regulate the CESA genes. However, none of the putative regulators appears to be regulated by MYB46, suggesting the multi-faceted nature of transcriptional regulation of secondary wall cellulose biosynthesis.
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Affiliation(s)
- Won-Chan Kim
- Department of Horticulture and Department of Forestry, Michigan State University, East Lansing, MI, 48824-1222, USA
- Department of Energy-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824-1222, USA
| | - Jae-Heung Ko
- Department of Plant & Environmental New Resources, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do, 446-701, Korea
- Bioenergy Center, Kyung Hee University, Yongin, Korea
| | - Joo-Yeol Kim
- Department of Horticulture and Department of Forestry, Michigan State University, East Lansing, MI, 48824-1222, USA
- Department of Energy-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824-1222, USA
| | - Jungmook Kim
- Department of Bioenergy Science and Technology, Chonnam National University, 333 Yongbongro, Buk-gu, Gwangju, 500-757, Korea
| | - Hyeun-Jong Bae
- Department of Bioenergy Science and Technology, Chonnam National University, 333 Yongbongro, Buk-gu, Gwangju, 500-757, Korea
| | - Kyung-Hwan Han
- Department of Horticulture and Department of Forestry, Michigan State University, East Lansing, MI, 48824-1222, USA
- Department of Energy-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824-1222, USA
- Department of Bioenergy Science and Technology, Chonnam National University, 333 Yongbongro, Buk-gu, Gwangju, 500-757, Korea
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118
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Abstract
Many microorganisms contain cellulases that are important for plant cell wall degradation and overall soil ecosystem functioning. At present, we have extensive biochemical knowledge of cellulases but little is known about the phylogenetic distribution of these enzymes. To address this, we analyzed the distribution of 21,985 genes encoding proteins related to cellulose utilization in 5,123 sequenced bacterial genomes. First, we identified the distribution of glycoside hydrolases involved in cellulose utilization and synthesis at different taxonomic levels, from the phylum to the strain. Cellulose degradation/utilization capabilities appeared in nearly all major groups and resulted in strains displaying various enzyme gene combinations. Potential cellulose degraders, having both cellulases and β-glucosidases, constituted 24% of all genomes whereas potential opportunistic strains, having β-glucosidases only, accounted for 56%. Finally, 20% of the bacteria have no relevant enzymes and do not rely on cellulose utilization. The latter group was primarily connected to specific bacterial lifestyles like autotrophy and parasitism. Cellulose degraders, as well as opportunists, have multiple enzymes with similar functions. However, the potential degraders systematically harbor about twice more β-glucosidases than their potential opportunistic relatives. Although scattered, the distribution of functional types, in bacterial lineages, is not random but mostly follows a Brownian motion evolution model. Degraders form clusters of relatives at the species level, whereas opportunists are clustered at the genus level. This information can form a mechanistic basis for the linking of changes in microbial community composition to soil ecosystem processes.
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119
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Chebli Y, Kaneda M, Zerzour R, Geitmann A. The cell wall of the Arabidopsis pollen tube--spatial distribution, recycling, and network formation of polysaccharides. PLANT PHYSIOLOGY 2012; 160:1940-55. [PMID: 23037507 PMCID: PMC3510122 DOI: 10.1104/pp.112.199729] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 10/02/2012] [Indexed: 05/17/2023]
Abstract
The pollen tube is a cellular protuberance formed by the pollen grain, or male gametophyte, in flowering plants. Its principal metabolic activity is the synthesis and assembly of cell wall material, which must be precisely coordinated to sustain the characteristic rapid growth rate and to ensure geometrically correct and efficient cellular morphogenesis. Unlike other model species, the cell wall of the Arabidopsis (Arabidopsis thaliana) pollen tube has not been described in detail. We used immunohistochemistry and quantitative image analysis to provide a detailed profile of the spatial distribution of the major cell wall polymers composing the Arabidopsis pollen tube cell wall. Comparison with predictions made by a mechanical model for pollen tube growth revealed the importance of pectin deesterification in determining the cell diameter. Scanning electron microscopy demonstrated that cellulose microfibrils are oriented in near longitudinal orientation in the Arabidopsis pollen tube cell wall, consistent with a linear arrangement of cellulose synthase CESA6 in the plasma membrane. The cellulose label was also found inside cytoplasmic vesicles and might originate from an early activation of cellulose synthases prior to their insertion into the plasma membrane or from recycling of short cellulose polymers by endocytosis. A series of strategic enzymatic treatments also suggests that pectins, cellulose, and callose are highly cross linked to each other.
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Affiliation(s)
- Youssef Chebli
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montreal, Quebec, Canada
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120
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del Campillo E, Gaddam S, Mettle-Amuah D, Heneks J. A tale of two tissues: AtGH9C1 is an endo-β-1,4-glucanase involved in root hair and endosperm development in Arabidopsis. PLoS One 2012; 7:e49363. [PMID: 23173056 PMCID: PMC3500288 DOI: 10.1371/journal.pone.0049363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 10/11/2012] [Indexed: 11/19/2022] Open
Abstract
Arabidopsis AtGH9C1 is an endo-β-1,4-glucanase possessing a carbohydrate-binding domain (CBM49). Analysis of AtGH9C1 expression by promoter-reporter GUS, RT-PCR, public transcriptome databases and GFP protein tagging demonstrated a high and selective expression of AtGH9C1 in root hairs and in the endosperm. Expression in root hair cells started prior to bulge formation and continued during hair elongation. AtGH9C1 expression increased with treatments that increase density (ACC) or length (sucrose) of root hairs. Expression in the endosperm extended sequentially to the micropylar, peripheral and chalazal compartments. A mutant with reduced AtGH9C1 expression had a delay in germination and a marked reduction in root hair presence. Complementation of the mutant partially improved both germination and root hair density. Experiments with ectopically expressed AtGH9C1-GFP with and without the CBM49, demonstrated that both forms of the protein are secreted and that CBM49 targets the protein to specific regions of the cell wall, but what makes these regions special is still unknown. The amino acid alignment of angiosperm GH9 genes with C-terminal extensions illustrate that AtGH9C1 belongs to a different clade than its tomato homolog, S1GH9C1. The latter has a CBM49 that was shown to bind crystalline cellulose. We suggest that AtGH9C1 is associated with the weakening of the cell wall during formation and growth of the root hair as well as with the sequential anterior-posterior breakdown of the endosperm cell wall that provides space for the growing embryo. Thus, is likely that the CBM49 of AtGH9C1 recognizes a form of cellulose or glucan polymer that is prevalent in the wall of these specialized tissues and that is different than the one recognized by S1GH9C1.
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Affiliation(s)
- Elena del Campillo
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America.
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121
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Leroux O. Collenchyma: a versatile mechanical tissue with dynamic cell walls. ANNALS OF BOTANY 2012; 110:1083-98. [PMID: 22933416 PMCID: PMC3478049 DOI: 10.1093/aob/mcs186] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Accepted: 07/06/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND Collenchyma has remained in the shadow of commercially exploited mechanical tissues such as wood and fibres, and therefore has received little attention since it was first described. However, collenchyma is highly dynamic, especially compared with sclerenchyma. It is the main supporting tissue of growing organs with walls thickening during and after elongation. In older organs, collenchyma may become more rigid due to changes in cell wall composition or may undergo sclerification through lignification of newly deposited cell wall material. While much is known about the systematic and organographic distribution of collenchyma, there is rather less information regarding the molecular architecture and properties of its cell walls. SCOPE AND CONCLUSIONS This review summarizes several aspects that have not previously been extensively discussed including the origin of the term 'collenchyma' and the history of its typology. As the cell walls of collenchyma largely determine the dynamic characteristics of this tissue, I summarize the current state of knowledge regarding their structure and molecular composition. Unfortunately, to date, detailed studies specifically focusing on collenchyma cell walls have not been undertaken. However, generating a more detailed understanding of the structural and compositional modifications associated with the transition from plastic to elastic collenchyma cell wall properties is likely to provide significant insights into how specific configurations of cell wall polymers result in specific functional properties. This approach, focusing on architecture and functional properties, is likely to provide improved clarity on the controversial definition of collenchyma.
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Affiliation(s)
- Olivier Leroux
- Botany and Plant Science and Ryan Institute, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland.
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122
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Davies LJ, Lilley CJ, Paul Knox J, Urwin PE. Syncytia formed by adult female Heterodera schachtii in Arabidopsis thaliana roots have a distinct cell wall molecular architecture. THE NEW PHYTOLOGIST 2012; 196:238-246. [PMID: 22803660 DOI: 10.1111/j.1469-8137.2012.04238.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
• Plant-parasitic cyst nematodes form a feeding site, termed a syncytium, through which the nematode obtains nutrients from the host plant to support nematode development. The structural features of cell walls of syncytial cells have yet to be elucidated. • Monoclonal antibodies to defined glycans and a cellulose-binding module were used to determine the cell wall architectures of syncytial and surrounding cells in the roots of Arabidopsis thaliana infected with the cyst nematode Heterodera schachtii. • Fluorescence imaging revealed that the cell walls of syncytia contain cellulose and the hemicelluloses xyloglucan and heteromannan. Heavily methyl-esterified pectic homogalacturonan and arabinan are abundant in syncytial cell walls; galactan could not be detected. This is suggestive of highly flexible syncytial cell walls. • This work provides important information on the structural architecture of the cell walls of this novel cell type and reveals factors that enable the feeding site to perform its functional requirements to support nematode development.
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Affiliation(s)
- Laura J Davies
- Centre for Plant Sciences, University of Leeds, Leeds, West Yorkshire LS2 9JT, UK
| | - Catherine J Lilley
- Centre for Plant Sciences, University of Leeds, Leeds, West Yorkshire LS2 9JT, UK
| | - J Paul Knox
- Centre for Plant Sciences, University of Leeds, Leeds, West Yorkshire LS2 9JT, UK
| | - P E Urwin
- Centre for Plant Sciences, University of Leeds, Leeds, West Yorkshire LS2 9JT, UK
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123
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Ruel K, Nishiyama Y, Joseleau JP. Crystalline and amorphous cellulose in the secondary walls of Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 193-194:48-61. [PMID: 22794918 DOI: 10.1016/j.plantsci.2012.05.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 05/09/2012] [Accepted: 05/11/2012] [Indexed: 06/01/2023]
Abstract
In the cell walls of higher plants, cellulose chains are present in crystalline microfibril, with an amorphous part at the surface, or present as amorphous material. To assess the distribution and relative occurrence of the two forms of cellulose in the inflorescence stem of Arabidopsis, we used two carbohydrate-binding modules, CBM3a and CBM28, specific for crystalline and amorphous cellulose, respectively, with immunogold detection in TEM. The binding of the two CBMs displayed specific patterns suggesting that the synthesis of cellulose leads to variable nanodomains of cellulose structures according to cell type. In developing cell walls, only CBM3a bound significantly to the incipient primary walls, indicating that at the onset of its deposition cellulose is in a crystalline structure. As the secondary wall develops, the labeling with both CBMs becomes more intense. The variation of the labeling pattern by CBM3a between transverse and longitudinal sections appeared related to microfibril orientation and differed between fibers and vessels. Although the two CBMs do not allow the description of the complete status of cellulose microstructures, they revealed the dynamics of the deposition of crystalline and amorphous forms of cellulose during wall formation and between cell types adapting cellulose microstructures to the cell function.
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Affiliation(s)
- Katia Ruel
- Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS UPR 5301), BP 53 38041 Grenoble CEDEX 9, France
| | - Yoshiharu Nishiyama
- Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS UPR 5301), BP 53 38041 Grenoble CEDEX 9, France
| | - Jean-Paul Joseleau
- Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS UPR 5301), BP 53 38041 Grenoble CEDEX 9, France.
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124
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Zhang M, Wu SC, Zhou W, Xu B. Imaging and Measuring Single-Molecule Interaction between a Carbohydrate-Binding Module and Natural Plant Cell Wall Cellulose. J Phys Chem B 2012; 116:9949-56. [DOI: 10.1021/jp304686q] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Mengmeng Zhang
- Single Molecule Study Laboratory,
Faculty of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, Georgia 30602, United
States
| | - Sheng-Cheng Wu
- Complex Carbohydrate
Research
Center and Department of Cellular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Wen Zhou
- Department of Chemical Engineering, Michigan Tech University, Houghton, Michigan 49931,
United States
| | - Bingqian Xu
- Single Molecule Study Laboratory,
Faculty of Engineering and Nanoscale Science and Engineering Center, University of Georgia, Athens, Georgia 30602, United
States
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125
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Domozych DS. The quest for four-dimensional imaging in plant cell biology: it's just a matter of time. ANNALS OF BOTANY 2012; 110:461-74. [PMID: 22628381 PMCID: PMC3394652 DOI: 10.1093/aob/mcs107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/04/2012] [Indexed: 05/22/2023]
Abstract
BACKGROUND Analysis of plant cell dynamics over time, or four-dimensional imaging (4-DI), represents a major goal of plant science. The ability to resolve structures in the third dimension within the cell or tissue during developmental events or in response to environmental or experimental stresses (i.e. 4-DI) is critical to our understanding of gene expression, post-expression modulations of macromolecules and sub-cellular system interactions. SCOPE Microscopy-based technologies have been profoundly integral to this type of investigation, and new and refined microscopy technologies now allow for the visualization of cell dynamics with unprecedented resolution, contrast and experimental versatility. However, certain realities of light and electron microscopy, choice of specimen and specimen preparation techniques limit the scope of readily attaining 4-DI. Today, the plant microscopist must use a combinatorial strategy whereby multiple microscopy-based investigations are used. Modern fluorescence, confocal laser scanning, transmission electron and scanning electron microscopy provide effective conduits for synthesizing data detailing live cell dynamics and highly resolved snapshots of specific cell structures that will ultimately lead to 4-DI. This review provides a synopsis of such technologies available.
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Affiliation(s)
- David S Domozych
- Department of Biology and Skidmore Microscopy Imaging Center, Skidmore College, Saratoga Springs, NY 12866, USA.
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126
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Anderson I, Abt B, Lykidis A, Klenk HP, Kyrpides N, Ivanova N. Genomics of aerobic cellulose utilization systems in actinobacteria. PLoS One 2012; 7:e39331. [PMID: 22723998 PMCID: PMC3377646 DOI: 10.1371/journal.pone.0039331] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 05/23/2012] [Indexed: 11/22/2022] Open
Abstract
Cellulose degrading enzymes have important functions in the biotechnology industry, including the production of biofuels from lignocellulosic biomass. Anaerobes including Clostridium species organize cellulases and other glycosyl hydrolases into large complexes known as cellulosomes. In contrast, aerobic actinobacteria utilize systems comprised of independently acting enzymes, often with carbohydrate binding domains. Numerous actinobacterial genomes have become available through the Genomic Encyclopedia of Bacteria and Archaea (GEBA) project. We identified putative cellulose-degrading enzymes belonging to families GH5, GH6, GH8, GH9, GH12, GH48, and GH51 in the genomes of eleven members of the actinobacteria. The eleven organisms were tested in several assays for cellulose degradation, and eight of the organisms showed evidence of cellulase activity. The three with the highest cellulase activity were Actinosynnema mirum, Cellulomonas flavigena, and Xylanimonas cellulosilytica. Cellobiose is known to induce cellulolytic enzymes in the model organism Thermobifida fusca, but only Nocardiopsis dassonvillei showed higher cellulolytic activity in the presence of cellobiose. In T. fusca, cellulases and a putative cellobiose ABC transporter are regulated by the transcriptional regulator CelR. Nine organisms appear to use the CelR site or a closely related binding site to regulate an ABC transporter. In some, CelR also regulates cellulases, while cellulases are controlled by different regulatory sites in three organisms. Mining of genome data for cellulose degradative enzymes followed by experimental verification successfully identified several actinobacteria species which were not previously known to degrade cellulose as cellulolytic organisms.
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Affiliation(s)
- Iain Anderson
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, California, USA.
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127
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Two SusD-like proteins encoded within a polysaccharide utilization locus of an uncultured ruminant Bacteroidetes phylotype bind strongly to cellulose. Appl Environ Microbiol 2012; 78:5935-7. [PMID: 22685144 DOI: 10.1128/aem.01164-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We demonstrate that two characteristic Sus-like proteins encoded within a polysaccharide utilization locus (PUL) bind strongly to cellulosic substrates and interact with plant primary cell walls. This shows associations between uncultured Bacteroidetes-affiliated lineages and cellulose in the rumen and thus presents new PUL-derived targets to pursue regarding plant biomass degradation.
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128
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Wilson SM, Burton RA, Collins HM, Doblin MS, Pettolino FA, Shirley N, Fincher GB, Bacic A. Pattern of deposition of cell wall polysaccharides and transcript abundance of related cell wall synthesis genes during differentiation in barley endosperm. PLANT PHYSIOLOGY 2012; 159:655-70. [PMID: 22510768 PMCID: PMC3375932 DOI: 10.1104/pp.111.192682] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Immunolabeling, combined with chemical analyses and transcript profiling, have provided a comprehensive temporal and spatial picture of the deposition and modification of cell wall polysaccharides during barley (Hordeum vulgare) grain development, from endosperm cellularization at 3 d after pollination (DAP) through differentiation to the mature grain at 38 DAP. (1→3)-β-D-Glucan appears transiently during cellularization but reappears in patches in the subaleurone cell walls around 20 DAP. (1→3, 1→4)-β-Glucan, the most abundant polysaccharide of the mature barley grain, accumulates throughout development. Arabino-(1-4)-β-D-xylan is deposited significantly earlier than we previously reported. This was attributable to the initial deposition of the polysaccharide in a highly substituted form that was not recognized by antibodies commonly used to detect arabino-(1-4)-β-D-xylans in sections of plant material. The epitopes needed for antibody recognition were exposed by pretreatment of sections with α-L-arabinofuranosidase; this procedure showed that arabino-(1-4)-β-D-xylans were deposited as early as 5 DAP and highlighted their changing structures during endosperm development. By 28 DAP labeling of hetero-(1→4)-β-D-mannan is observed in the walls of the starchy endosperm but not in the aleurone walls. Although absent in mature endosperm cell walls we now show that xyloglucan is present transiently from 3 until about 6 DAP and disappears by 8 DAP. Quantitative reverse transcription-polymerase chain reaction of transcripts for GLUCAN SYNTHASE-LIKE, Cellulose Synthase, and CELLULOSE SYNTHASE-LIKE genes were consistent with the patterns of polysaccharide deposition. Transcript profiling of some members from the Carbohydrate-Active Enzymes database glycosyl transferase families GT61, GT47, and GT43, previously implicated in arabino-(1-4)-β-d-xylan biosynthesis, confirms their presence during grain development.
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Affiliation(s)
- Sarah M Wilson
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Botany, University of Melbourne, Victoria 3010, Australia.
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129
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Goss CA, Brockmann DJ, Bushoven JT, Roberts AW. A CELLULOSE SYNTHASE (CESA) gene essential for gametophore morphogenesis in the moss Physcomitrella patens. PLANTA 2012; 235:1355-67. [PMID: 22215046 DOI: 10.1007/s00425-011-1579-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 12/19/2011] [Indexed: 05/11/2023]
Abstract
In seed plants, different groups of orthologous genes encode the CELLULOSE SYNTHASE (CESA) proteins that are responsible for cellulose biosynthesis in primary and secondary cell walls. The seven CESA sequences of the moss Physcomitrella patens (Hedw.) B. S. G. form a monophyletic sister group to seed plant CESAs, consistent with independent CESA diversification and specialization in moss and seed plant lines. The role of PpCESA5 in the development of P. patens was investigated by targeted mutagenesis. The cesa5 knockout lines were tested for cellulose deficiency using carbohydrate-binding module affinity cytochemistry and the morphology of the leafy gametophores was analyzed by 3D reconstruction of confocal images. No defects were identified in the development of the filamentous protonema or in production of bud initials that normally give rise to the leafy gametophores. However, the gametophore buds were cellulose deficient and defects in subsequent cell expansion, cytokinesis, and leaf initiation resulted in the formation of irregular cell clumps instead of leafy shoots. Analysis of the cesa5 knockout phenotype indicates that a biophysical model of organogenesis can be extended to the moss gametophore shoot apical meristem.
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Affiliation(s)
- Chessa A Goss
- Department of Biological Sciences, CBLS, University of Rhode Island, Kingston, RI 02881, USA
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130
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Analysis of crystallinity changes in cellulose II polymers using carbohydrate-binding modules. Carbohydr Polym 2012; 89:213-21. [DOI: 10.1016/j.carbpol.2012.02.073] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 02/27/2012] [Accepted: 02/29/2012] [Indexed: 11/20/2022]
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131
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Harpaz-Saad S, Western TL, Kieber JJ. The FEI2-SOS5 pathway and CELLULOSE SYNTHASE 5 are required for cellulose biosynthesis in the Arabidopsis seed coat and affect pectin mucilage structure. PLANT SIGNALING & BEHAVIOR 2012; 7:285-8. [PMID: 22353871 PMCID: PMC3405700 DOI: 10.4161/psb.18819] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A common adaptation in angiosperms is the deposition of hydrophilic mucilage into the apoplast of seed coat epidermal cells during the course of their differentiation. Upon imbibition, seed mucilage, composed mainly of carbohydrates (i.e. pectins, hemicelluloses and glycans) expands rapidly, encapsulating the seed and aiding in seed dispersal and germination. The FEI1/FEI2 receptor-like kinases and the SOS5 extracellular GPI-anchored protein were previously shown to act on a pathway regulating cellulose biosynthesis during Arabidopsis root elongation. In the highlighted study, we demonstrated that FEI2 and SOS5 regulate the production of the cellulosic rays deposited across the inner adherent-layer of seed mucilage. Mutations in either fei2 or sos5 disrupted the formation of rays, which was associated with an increase in the soluble, outer layer of pectin mucilage and accompanied by a reduction in the inner adherent-layer. Mutations in CELLULOSE SYNTHASE 5 also led to reduced rays and mal-partitioning of the pectic component of seed mucilage, further establishing a structural role for cellulose in seed mucilage. Here, we show that FEI2 expressed from a CaMV 35S promoter complemented both root and seed mucilage defects of the fei1 fei2 double mutant. In contrast, expression of FEI1 from a 35S promoter complemented the root, but not the seed phenotype of the fei1 fei2 double mutant, suggesting that unlike in the root, FEI2 plays a unique and non-redundant role in the regulation of cellulose synthesis in seed mucilage. Altogether, these data suggest a novel role for cellulose in anchoring the pectic component of seed mucilage to the seed surface and indicate that the FEI2 protein has a function distinct from that of FEI1, despite the high sequence similarity of these RLKs.
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Affiliation(s)
| | | | - Joseph J. Kieber
- Biology Department; University of North Carolina; Chapel Hill, NC USA
- Correspondence to: Joseph Kieber;
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132
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Taylor CB, Talib MF, McCabe C, Bu L, Adney WS, Himmel ME, Crowley MF, Beckham GT. Computational investigation of glycosylation effects on a family 1 carbohydrate-binding module. J Biol Chem 2012; 287:3147-55. [PMID: 22147693 PMCID: PMC3270969 DOI: 10.1074/jbc.m111.270389] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 12/01/2011] [Indexed: 11/06/2022] Open
Abstract
Carbohydrate-binding modules (CBMs) are ubiquitous components of glycoside hydrolases, which degrade polysaccharides in nature. CBMs target specific polysaccharides, and CBM binding affinity to cellulose is known to be proportional to cellulase activity, such that increasing binding affinity is an important component of performance improvement. To ascertain the impact of protein and glycan engineering on CBM binding, we use molecular simulation to quantify cellulose binding of a natively glycosylated Family 1 CBM. To validate our approach, we first examine aromatic-carbohydrate interactions on binding, and our predictions are consistent with previous experiments, showing that a tyrosine to tryptophan mutation yields a 2-fold improvement in binding affinity. We then demonstrate that enhanced binding of 3-6-fold over a nonglycosylated CBM is achieved by the addition of a single, native mannose or a mannose dimer, respectively, which has not been considered previously. Furthermore, we show that the addition of a single, artificial glycan on the anterior of the CBM, with the native, posterior glycans also present, can have a dramatic impact on binding affinity in our model, increasing it up to 140-fold relative to the nonglycosylated CBM. These results suggest new directions in protein engineering, in that modifying glycosylation patterns via heterologous expression, manipulation of culture conditions, or introduction of artificial glycosylation sites, can alter CBM binding affinity to carbohydrates and may thus be a general strategy to enhance cellulase performance. Our results also suggest that CBM binding studies should consider the effects of glycosylation on binding and function.
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Affiliation(s)
| | - M. Faiz Talib
- From the Departments of Chemical and Biomolecular Engineering and
| | - Clare McCabe
- From the Departments of Chemical and Biomolecular Engineering and
- Chemistry, Vanderbilt University, Nashville, Tennessee 37235
| | | | - William S. Adney
- the Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, and
| | - Michael E. Himmel
- the Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, and
| | - Michael F. Crowley
- the Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, and
| | - Gregg T. Beckham
- the National Bioenergy Center and
- the Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401
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133
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Abstract
Cellulose is generally found in the context of complex plant cell wall materials and mostly in association with other glycans. Cellulose-directed carbohydrate-binding modules (CBMs) can be readily adapted to a range of methods for the in situ imaging of cellulose structures within plant cell walls or other cellulose-based materials. Protocols for the preparation and selection of plant materials, their fixation and processing for preparation of sections for CBM labeling, and fluorescence imaging procedures are described. Approaches to direct methods in which CBMs are directly coupled to fluorophores and indirect methods in which staged incubations with secondary reagents are used for the fluorescence imaging of CBM binding to materials are discussed and presented.
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Affiliation(s)
- J Paul Knox
- Faculty of Biological Sciences, Centre for Plant Sciences, University of Leeds, Leeds, United Kingdom
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134
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Haughn GW, Western TL. Arabidopsis Seed Coat Mucilage is a Specialized Cell Wall that Can be Used as a Model for Genetic Analysis of Plant Cell Wall Structure and Function. FRONTIERS IN PLANT SCIENCE 2012; 3:64. [PMID: 22645594 PMCID: PMC3355795 DOI: 10.3389/fpls.2012.00064] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 03/16/2012] [Indexed: 05/17/2023]
Abstract
Arabidopsis seed coat epidermal cells produce a large quantity of mucilage that is extruded upon exposure to water. Chemical analyses and cell biological techniques suggest that this mucilage represents a specialized type of secondary cell wall composed primarily of pectin with lesser amounts of cellulose and xyloglucan. Once extruded, the mucilage capsule has a distinctive structure with an outer non-adherent layer that is easily removed by shaking in water, and an inner adherent layer that can only be removed with strong acid or base. Most of the cellulose in the mucilage is present in the inner layer and is responsible at least in part for its adherence to the seed. There are also differences in the pectin composition between the two layers that could contribute to the difference in adherence. The Arabidopsis seed coat epidermis and its mucilage are not essential for seed viability or germination. This dispensability, combined with the fact that the epidermal cells synthesize an accessible pectin-rich cell wall at a specific time in development, makes them well suited as a genetic model for studying cell wall biogenesis, function, and regulation. Mutants defective in seed mucilage identified by both forward and reverse genetic analyses are proving useful in establishing connections between carbohydrate structure and cell wall properties in vivo. In the future, genetic engineering of seed coat mucilage carbohydrates should prove useful for testing hypotheses concerning cell wall structure and function.
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Affiliation(s)
- George W. Haughn
- Department of Botany, University of British ColumbiaVancouver, BC, Canada
- *Correspondence: George W. Haughn, Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4. e-mail:
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135
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Harpaz-Saad S, McFarlane HE, Xu S, Divi UK, Forward B, Western TL, Kieber JJ. Cellulose synthesis via the FEI2 RLK/SOS5 pathway and cellulose synthase 5 is required for the structure of seed coat mucilage in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 68:941-53. [PMID: 21883548 DOI: 10.1111/j.1365-313x.2011.04760.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The seeds of Arabidopsis thaliana and many other plants are surrounded by a pectinaceous mucilage that aids in seed hydration and germination. Mucilage is synthesized during seed development within maternally derived seed coat mucilage secretory cells (MSCs), and is released to surround the seed upon imbibition. The FEI1/FEI2 receptor-like kinases and the SOS5 extracellular GPI-anchored protein were shown previously to act on a pathway that regulates the synthesis of cellulose in Arabidopsis roots. Here, we demonstrate that both FEI2 and SOS5 also play a role in the synthesis of seed mucilage. Disruption of FEI2 or SOS5 leads to a reduction in the rays of cellulose observed across the seed mucilage inner layer, which alters the structure of the mucilage in response to hydration. Mutations in CESA5, which disrupts an isoform of cellulose synthase involved in primary cell wall synthesis, result in a similar seed mucilage phenotype. The data indicate that CESA5-derived cellulose plays an important role in the synthesis and structure of seed coat mucilage and that the FEI2/SOS5 pathway plays a role in the regulation of cellulose synthesis in MSCs. Moreover, these results establish a novel structural role for cellulose in anchoring the pectic component of seed coat mucilage to the seed surface.
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Affiliation(s)
- Smadar Harpaz-Saad
- University of North Carolina, Biology Department, Chapel Hill, NC 27599, USA
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136
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Fernandes AN, Thomas LH, Altaner CM, Callow P, Forsyth VT, Apperley DC, Kennedy CJ, Jarvis MC. Nanostructure of cellulose microfibrils in spruce wood. Proc Natl Acad Sci U S A 2011; 108:E1195-203. [PMID: 22065760 PMCID: PMC3223458 DOI: 10.1073/pnas.1108942108] [Citation(s) in RCA: 347] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The structure of cellulose microfibrils in wood is not known in detail, despite the abundance of cellulose in woody biomass and its importance for biology, energy, and engineering. The structure of the microfibrils of spruce wood cellulose was investigated using a range of spectroscopic methods coupled to small-angle neutron and wide-angle X-ray scattering. The scattering data were consistent with 24-chain microfibrils and favored a "rectangular" model with both hydrophobic and hydrophilic surfaces exposed. Disorder in chain packing and hydrogen bonding was shown to increase outwards from the microfibril center. The extent of disorder blurred the distinction between the I alpha and I beta allomorphs. Chains at the surface were distinct in conformation, with high levels of conformational disorder at C-6, less intramolecular hydrogen bonding and more outward-directed hydrogen bonding. Axial disorder could be explained in terms of twisting of the microfibrils, with implications for their biosynthesis.
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Affiliation(s)
- Anwesha N. Fernandes
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonnington Campus, Leicestershire LE12 5RD, United Kingdom
| | - Lynne H. Thomas
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Clemens M. Altaner
- New Zealand School of Forestry, University of Canterbury, Christchurch 8140, New Zealand
| | - Philip Callow
- Institut Laue-Langevin, 38042 Grenoble Cedex 9, France
| | - V. Trevor Forsyth
- Institut Laue-Langevin, 38042 Grenoble Cedex 9, France
- Environment, Physical Sciences, and Applied Mathematics/Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - David C. Apperley
- Chemistry Department, Durham University, Durham DH1 3LE, United Kingdom
| | - Craig J. Kennedy
- Historic Scotland, Longmore House, Salisbury Place, Edinburgh EH9 1SH, United Kingdom; and
| | - Michael C. Jarvis
- School of Chemistry, Glasgow University, Glasgow G12 8QQ, United Kingdom
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137
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Mendu V, Stork J, Harris D, DeBolt S. Cellulose synthesis in two secondary cell wall processes in a single cell type. PLANT SIGNALING & BEHAVIOR 2011; 6:1638-43. [PMID: 22057330 PMCID: PMC3329324 DOI: 10.4161/psb.6.11.17709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plant cells have a rigid cell wall that constrains internal turgor pressure yet extends in a regulated and organized manner to allow the cell to acquire shape. The primary load-bearing macromolecule of a plant cell wall is cellulose, which forms crystalline microfibrils that are organized with respect to a cell's function and shape requirements. A primary cell wall is deposited during expansion whereas secondary cell wall is synthesized post expansion during differentiation. A complex form of asymmetrical cellular differentiation occurs in Arabidopsis seed coat epidermal cells, where we have recently shown that two secondary cell wall processes occur that utilize different cellulose synthase (CESA) proteins. One process is to produce pectinaceous mucilage that expands upon hydration and the other is a radial wall thickening that reinforced the epidermal cell structure. Our data illustrate polarized specialization of CESA5 in facilitating mucilage attachment to the parent seed and CESA2, CESA5 and CESA9 in radial cell wall thickening and formation of the columella. Herein, we present a model for the complexity of cellulose biosynthesis in this highly differentiated cell type with further evidence supporting each cellulosic secondary cell wall process.
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Affiliation(s)
- Venugopal Mendu
- Department of Horticulture, University of Kentucky; Lexington, KY USA
| | - Jozsef Stork
- Department of Horticulture, University of Kentucky; Lexington, KY USA
| | - Darby Harris
- Department of Horticulture, University of Kentucky; Lexington, KY USA
- Plant Physiology; Biochemistry and Molecular Biology Program; University of Kentucky; Lexington, KY USA
| | - Seth DeBolt
- Department of Horticulture, University of Kentucky; Lexington, KY USA
- Plant Physiology; Biochemistry and Molecular Biology Program; University of Kentucky; Lexington, KY USA
- Correspondence to: Seth DeBolt,
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138
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Kljun A, Benians TAS, Goubet F, Meulewaeter F, Knox JP, Blackburn RS. Comparative Analysis of Crystallinity Changes in Cellulose I Polymers Using ATR-FTIR, X-ray Diffraction, and Carbohydrate-Binding Module Probes. Biomacromolecules 2011; 12:4121-6. [DOI: 10.1021/bm201176m] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alenka Kljun
- Sustainable Materials Research Group,
Centre for Technical Textiles, University of Leeds, Leeds LS2 9JT, U.K
| | - Thomas A. S. Benians
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | | | | | - J. Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Richard S. Blackburn
- Sustainable Materials Research Group,
Centre for Technical Textiles, University of Leeds, Leeds LS2 9JT, U.K
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139
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Yu L, Zhou Y, Knox JP. Ginseng root water-extracted pectic polysaccharides originate from secretory cavities. PLANTA 2011; 234:487-99. [PMID: 21533753 DOI: 10.1007/s00425-011-1417-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 04/12/2011] [Indexed: 05/04/2023]
Abstract
A range of molecular probes for cell wall polysaccharides has been used to explore the structure and location of water-extracted pectic polysaccharides occurring in fractions isolated from ginseng roots. The LM19 homogalacturonan (HG) epitope was abundant in an HG fraction and analysis of LM19 binding to a rhamnogalacturonan-I (RG-I) rich-fraction indicated that the LM19 epitope is sensitive to acetylation. A specific RG-I epitope (LM16), four arabinogalactan-protein (AGP) epitopes (LM2, LM14, JIM16, MAC207) and an extensin epitope (JIM20) were found to be abundant and co-located in several isolated polysaccharide fractions including an arabinogalactan fraction and two RG-I fractions. Detection of the RG-I, AGP and extensin epitopes identified in isolated polysaccharide fractions in sections of ginseng roots indicated that they were most abundant in secretory cavities found in the cortical regions of ginseng roots. In addition, the immunocytochemical study indicated that polysaccharide epitope masking is a widespread phenomenon in the primary cell walls of ginseng roots.
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Affiliation(s)
- Li Yu
- School of Life Sciences, Northeast Normal University, Changchun 130024, People's Republic of China
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140
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Mendu V, Griffiths JS, Persson S, Stork J, Downie AB, Voiniciuc C, Haughn GW, DeBolt S. Subfunctionalization of cellulose synthases in seed coat epidermal cells mediates secondary radial wall synthesis and mucilage attachment. PLANT PHYSIOLOGY 2011; 157:441-53. [PMID: 21750228 PMCID: PMC3165890 DOI: 10.1104/pp.111.179069] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 07/06/2011] [Indexed: 05/17/2023]
Abstract
Arabidopsis (Arabidopsis thaliana) epidermal seed coat cells follow a complex developmental program where, following fertilization, cells of the ovule outer integument differentiate into a unique cell type. Two hallmarks of these cells are the production of a doughnut-shaped apoplastic pocket filled with pectinaceous mucilage and the columella, a thick secondary cell wall. Cellulose is thought to be a key component of both these secondary cell wall processes. Here, we investigated the role of cellulose synthase (CESA) subunits CESA2, CESA5, and CESA9 in the seed coat epidermis. We characterized the roles of these CESA proteins in the seed coat by analyzing cell wall composition and morphology in cesa mutant lines. Mutations in any one of these three genes resulted in lower cellulose content, a loss of cell shape uniformity, and reduced radial wall integrity. In addition, we found that attachment of the mucilage halo to the parent seed following extrusion is maintained by cellulose-based connections requiring CESA5. Hence, we show that cellulose fulfills an adhesion role between the extracellular mucilage matrix and the parent cell in seed coat epidermal cells. We propose that mucilage remains attached to the seed coat through interactions between components in the seed mucilage and cellulose. Our data suggest that CESA2 and CESA9 serve in radial wall reinforcement, as does CESA5, but CESA5 also functions in mucilage biosynthesis. These data suggest unique roles for different CESA subunits in one cell type and illustrate a complex role for cellulose biosynthesis in plant developmental biology.
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141
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Sullivan S, Ralet MC, Berger A, Diatloff E, Bischoff V, Gonneau M, Marion-Poll A, North HM. CESA5 is required for the synthesis of cellulose with a role in structuring the adherent mucilage of Arabidopsis seeds. PLANT PHYSIOLOGY 2011; 156:1725-39. [PMID: 21705653 PMCID: PMC3149949 DOI: 10.1104/pp.111.179077] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 06/22/2011] [Indexed: 05/17/2023]
Abstract
Imbibed Arabidopsis (Arabidopsis thaliana) seeds are encapsulated by mucilage that is formed of hydrated polysaccharides released from seed coat epidermal cells. The mucilage is structured with water-soluble and adherent layers, with cellulose present uniquely in an inner domain of the latter. Using a reverse-genetic approach to identify the cellulose synthases (CESAs) that produce mucilage cellulose, cesa5 mutants were shown to be required for the correct formation of these layers. Expression of CESA5 in the seed coat was specific to epidermal cells and coincided with the accumulation of mucilage polysaccharides in their apoplast. Analysis of sugar composition showed that although total sugar composition or amounts were unchanged, their partition between layers was different in the mutant, with redistribution from adherent to water-soluble mucilage. The macromolecular characteristics of the water-soluble mucilage were also modified. In accordance with a role for CESA5 in mucilage cellulose synthesis, crystalline cellulose contents were reduced in mutant seeds and birefringent microfibrils were absent from adherent mucilage. Although the mucilage-modified5 mutant showed similar defects to cesa5 in the distribution of sugar components between water-soluble and adherent mucilage, labeling of residual adherent mucilage indicated that cesa5 contained less cellulose and less pectin methyl esterification. Together, the results demonstrate that CESA5 plays a major and essential role in cellulose production in seed mucilage, which is critical for the establishment of mucilage structured in layers and domains.
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142
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Leroux O, Knox JP, Masschaele B, Bagniewska-Zadworna A, Marcus SE, Claeys M, van Hoorebeke L, Viane RLL. An extensin-rich matrix lines the carinal canals in Equisetum ramosissimum, which may function as water-conducting channels. ANNALS OF BOTANY 2011; 108:307-19. [PMID: 21752793 PMCID: PMC3143055 DOI: 10.1093/aob/mcr161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS The anatomy of Equisetum stems is characterized by the occurrence of vallecular and carinal canals. Previous studies on the carinal canals in several Equisetum species suggest that they convey water from one node to another. METHODS Cell wall composition and ultrastructure have been studied using immunocytochemistry and electron microscopy, respectively. Serial sectioning and X-ray computed tomography were employed to examine the internode-node-internode transition of Equisetum ramosissimum. KEY RESULTS The distribution of the LM1 and JIM20 extensin epitopes is restricted to the lining of carinal canals. The monoclonal antibodies JIM5 and LM19 directed against homogalacturonan with a low degree of methyl esterification and the CBM3a probe recognizing crystalline cellulose also bound to this lining. The xyloglucan epitopes recognized by LM15 and CCRC-M1 were only detected in this lining after pectate lyase treatment. The carinal canals, connecting consecutive rings of nodal xylem, are formed by the disruption and dissolution of protoxylem elements during elongation of the internodes. Their inner surface appears smooth compared with that of vallecular canals. CONCLUSIONS The carinal canals in E. ramosissimum have a distinctive lining containing pectic homogalacturonan, cellulose, xyloglucan and extensin. These canals might function as water-conducting channels which would be especially important during the elongation of the internodes when protoxylem is disrupted and the metaxylem is not yet differentiated. How the molecularly distinct lining relates to the proposed water-conducting function of the carinal canals requires further study. Efforts to elucidate the spatial and temporal distribution of cell wall polymers in a taxonomically broad range of plants will probably provide more insight into the structural-functional relationships of individual cell wall components or of specific configurations of cell wall polymers.
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Affiliation(s)
- O Leroux
- Pteridology, Department of Biology, Ghent University, KL Ledeganckstraat 35, B-9000 Ghent, Belgium
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143
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Park S, Szumlanski AL, Gu F, Guo F, Nielsen E. A role for CSLD3 during cell-wall synthesis in apical plasma membranes of tip-growing root-hair cells. Nat Cell Biol 2011; 13:973-80. [PMID: 21765420 DOI: 10.1038/ncb2294] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 06/07/2011] [Indexed: 01/29/2023]
Abstract
In plants, cell shape is defined by the cell wall, and changes in cell shape and size are dictated by modification of existing cell walls and deposition of newly synthesized cell-wall material. In root hairs, expansion occurs by a process called tip growth, which is shared by root hairs, pollen tubes and fungal hyphae. We show that cellulose-like polysaccharides are present in root-hair tips, and de novo synthesis of these polysaccharides is required for tip growth. We also find that eYFP-CSLD3 proteins, but not CESA cellulose synthases, localize to a polarized plasma-membrane domain in root hairs. Using biochemical methods and genetic complementation of a csld3 mutant with a chimaeric CSLD3 protein containing a CESA6 catalytic domain, we provide evidence that CSLD3 represents a distinct (1→4)-β-glucan synthase activity in apical plasma membranes during tip growth in root-hair cells.
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Affiliation(s)
- Sungjin Park
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
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144
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Ultrastructure and composition of cell wall appositions in the roots of Asplenium (Polypodiales). Micron 2011; 42:863-70. [PMID: 21708469 DOI: 10.1016/j.micron.2011.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 05/31/2011] [Accepted: 06/02/2011] [Indexed: 12/21/2022]
Abstract
Cell wall appositions (CWAs), formed by the deposition of extra wall material at the contact site with microbial organisms, are an integral part of the response of plants to microbial challenge. Detailed histological studies of CWAs in fern roots do not exist. Using light and electron microscopy we examined the (ultra)structure of CWAs in the outer layers of roots of Asplenium species. All cell walls studded with CWAs were impregnated with yellow-brown pigments. CWAs had different shapes, ranging from warts to elongated branched structures, as observed with scanning and transmission electron microscopy. Ultrastructural study further showed that infecting fungi grow intramurally and that they are immobilized by CWAs when attempting to penetrate intracellularly. Immunolabelling experiments using monoclonal antibodies indicated pectic homogalacturonan, xyloglucan, mannan and cellulose in the CWAs, but tests for lignins and callose were negative. We conclude that these appositions are defense-related structures made of a non-lignified polysaccharide matrix on which phenolic compounds are deposited in order to create a barrier protecting the root against infections.
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145
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Fusion of a family 9 cellulose-binding module improves catalytic potential of Clostridium thermocellum cellodextrin phosphorylase on insoluble cellulose. Appl Microbiol Biotechnol 2011; 92:551-60. [DOI: 10.1007/s00253-011-3346-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 05/02/2011] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
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146
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Brás JLA, Cartmell A, Carvalho ALM, Verzé G, Bayer EA, Vazana Y, Correia MAS, Prates JAM, Ratnaparkhe S, Boraston AB, Romão MJ, Fontes CMGA, Gilbert HJ. Structural insights into a unique cellulase fold and mechanism of cellulose hydrolysis. Proc Natl Acad Sci U S A 2011; 108:5237-42. [PMID: 21393568 PMCID: PMC3069175 DOI: 10.1073/pnas.1015006108] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Clostridium thermocellum is a well-characterized cellulose-degrading microorganism. The genome sequence of C. thermocellum encodes a number of proteins that contain type I dockerin domains, which implies that they are components of the cellulose-degrading apparatus, but display no significant sequence similarity to known plant cell wall-degrading enzymes. Here, we report the biochemical properties and crystal structure of one of these proteins, designated CtCel124. The protein was shown to be an endo-acting cellulase that displays a single displacement mechanism and acts in synergy with Cel48S, the major cellulosomal exo-cellulase. The crystal structure of CtCel124 in complex with two cellotriose molecules, determined to 1.5 Å, displays a superhelical fold in which a constellation of α-helices encircle a central helix that houses the catalytic apparatus. The catalytic acid, Glu96, is located at the C-terminus of the central helix, but there is no candidate catalytic base. The substrate-binding cleft can be divided into two discrete topographical domains in which the bound cellotriose molecules display twisted and linear conformations, respectively, suggesting that the enzyme may target the interface between crystalline and disordered regions of cellulose.
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Affiliation(s)
- Joana L. A. Brás
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Alan Cartmell
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712
| | - Ana Luísa M. Carvalho
- Rede de Química e Tecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Genny Verzé
- Rede de Química e Tecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
- Biocrystallography Laboratory, Department of Biotechnology, University of Verona, 37129 Verona, Italy
| | - Edward A. Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100 Israel; and
| | - Yael Vazana
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100 Israel; and
| | - Márcia A. S. Correia
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - José A. M. Prates
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Supriya Ratnaparkhe
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712
| | - Alisdair B. Boraston
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8W 3P6
| | - Maria J. Romão
- Rede de Química e Tecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Carlos M. G. A. Fontes
- Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisbon, Portugal
| | - Harry J. Gilbert
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712
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147
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Moller IE, De Fine Licht HH, Harholt J, Willats WGT, Boomsma JJ. The dynamics of plant cell-wall polysaccharide decomposition in leaf-cutting ant fungus gardens. PLoS One 2011; 6:e17506. [PMID: 21423735 PMCID: PMC3053354 DOI: 10.1371/journal.pone.0017506] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 02/04/2011] [Indexed: 11/18/2022] Open
Abstract
The degradation of live plant biomass in fungus gardens of leaf-cutting ants is poorly characterised but fundamental for understanding the mutual advantages and efficiency of this obligate nutritional symbiosis. Controversies about the extent to which the garden-symbiont Leucocoprinus gongylophorus degrades cellulose have hampered our understanding of the selection forces that induced large scale herbivory and of the ensuing ecological footprint of these ants. Here we use a recently established technique, based on polysaccharide microarrays probed with antibodies and carbohydrate binding modules, to map the occurrence of cell wall polymers in consecutive sections of the fungus garden of the leaf-cutting ant Acromyrmex echinatior. We show that pectin, xyloglucan and some xylan epitopes are degraded, whereas more highly substituted xylan and cellulose epitopes remain as residuals in the waste material that the ants remove from their fungus garden. These results demonstrate that biomass entering leaf-cutting ant fungus gardens is only partially utilized and explain why disproportionally large amounts of plant material are needed to sustain colony growth. They also explain why substantial communities of microbial and invertebrate symbionts have evolved associations with the dump material from leaf-cutting ant nests, to exploit decomposition niches that the ant garden-fungus does not utilize. Our approach thus provides detailed insight into the nutritional benefits and shortcomings associated with fungus-farming in ants.
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Affiliation(s)
- Isabel E Moller
- Copenhagen Biocenter, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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148
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Leroux O, Bagniewska-Zadworna A, Rambe SK, Knox JP, Marcus SE, Bellefroid E, Stubbe D, Chabbert B, Habrant A, Claeys M, Viane RLL. Non-lignified helical cell wall thickenings in root cortical cells of Aspleniaceae (Polypodiales): histology and taxonomical significance. ANNALS OF BOTANY 2011; 107:195-207. [PMID: 21118842 PMCID: PMC3025727 DOI: 10.1093/aob/mcq225] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
BACKGROUND AND AIMS Extraxylary helical cell wall thickenings in vascular plants are not well documented, except for those in orchid velamen tissues which have been studied extensively. Reports on their occurrence in ferns exist, but detailed information is missing. The aim of this study is to focus on the broad patterns of structure and composition and to study the taxonomic occurrence of helical cell wall thickenings in the fern family Aspleniaceae. METHODS Structural and compositional aspects of roots have been examined by means of light, electron, epifluorescence and laser scanning confocal microscopy. To assess the taxonomical distribution of helical cell wall thickenings a molecular phylogenetic analysis based on rbcL sequences of 64 taxa was performed. KEY RESULTS The helical cell wall thickenings of all examined species showed considerable uniformity of design. The pattern consists of helical, regularly bifurcating and anastomosing strands. Compositionally, the cell wall thickenings were found to be rich in homogalacturonan, cellulose, mannan and xyloglucan. Thioacidolysis confirmed our negative phloroglucinol staining tests, demonstrating the absence of lignins in the root cortex. All taxa with helical cell wall thickenings formed a monophyletic group supported by a 100 % bootstrap value and composed of mainly epiphytic species. CONCLUSIONS This is the first report of non-lignified pectin-rich secondary cell walls in ferns. Based on our molecular analysis, we reject the hypothesis of parallel evolution of helical cell wall thickenings in Aspleniaceae. Helical cell wall thickenings can mechanically stabilize the cortex tissue, allowing maximal uptake of water and nutrients during rainfall events. In addition, it can also act as a boundary layer increasing the diffusive pathway towards the atmosphere, preventing desiccation of the stele of epiphytic growing species.
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Affiliation(s)
- O. Leroux
- Pteridology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - A. Bagniewska-Zadworna
- Department of General Botany, Institute of Experimental Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - S. K. Rambe
- NSSE–Biology, National Institute of Education, Nanyang Technological University, Nanyang Walk 1, 637616, Singapore
| | - J. P. Knox
- Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - S. E. Marcus
- Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - E. Bellefroid
- Pteridology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - D. Stubbe
- Research Group Mycology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
| | - B. Chabbert
- URCA, UMR Fractionnement Agroressources & Environment 614, F-51686 Reims, France
| | - A. Habrant
- URCA, UMR Fractionnement Agroressources & Environment 614, F-51686 Reims, France
| | - M. Claeys
- Nematology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Gent, Belgium
| | - R. L. L. Viane
- Pteridology, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
- For correspondence. E-mail
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149
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Dam P, Kataeva I, Yang SJ, Zhou F, Yin Y, Chou W, Poole FL, Westpheling J, Hettich R, Giannone R, Lewis DL, Kelly R, Gilbert HJ, Henrissat B, Xu Y, Adams MWW. Insights into plant biomass conversion from the genome of the anaerobic thermophilic bacterium Caldicellulosiruptor bescii DSM 6725. Nucleic Acids Res 2011; 39:3240-54. [PMID: 21227922 PMCID: PMC3082886 DOI: 10.1093/nar/gkq1281] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Caldicellulosiruptor bescii DSM 6725 utilizes various polysaccharides and grows efficiently on untreated high-lignin grasses and hardwood at an optimum temperature of ∼80°C. It is a promising anaerobic bacterium for studying high-temperature biomass conversion. Its genome contains 2666 protein-coding sequences organized into 1209 operons. Expression of 2196 genes (83%) was confirmed experimentally. At least 322 genes appear to have been obtained by lateral gene transfer (LGT). Putative functions were assigned to 364 conserved/hypothetical protein (C/HP) genes. The genome contains 171 and 88 genes related to carbohydrate transport and utilization, respectively. Growth on cellulose led to the up-regulation of 32 carbohydrate-active (CAZy), 61 sugar transport, 25 transcription factor and 234 C/HP genes. Some C/HPs were overproduced on cellulose or xylan, suggesting their involvement in polysaccharide conversion. A unique feature of the genome is enrichment with genes encoding multi-modular, multi-functional CAZy proteins organized into one large cluster, the products of which are proposed to act synergistically on different components of plant cell walls and to aid the ability of C. bescii to convert plant biomass. The high duplication of CAZy domains coupled with the ability to acquire foreign genes by LGT may have allowed the bacterium to rapidly adapt to changing plant biomass-rich environments.
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Affiliation(s)
- Phuongan Dam
- Institute of Bioinformatics, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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DeMartini JD, Pattathil S, Avci U, Szekalski K, Mazumder K, Hahn MG, Wyman CE. Application of monoclonal antibodies to investigate plant cell wall deconstruction for biofuels production. ENERGY & ENVIRONMENTAL SCIENCE 2011. [PMID: 0 DOI: 10.1039/c1ee02112e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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