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Begum RA, Messenger DJ, Fry SC. Making and breaking of boron bridges in the pectic domain rhamnogalacturonan-II at apoplastic pH in vivo and in vitro. Plant J 2023; 113:1310-1329. [PMID: 36658763 PMCID: PMC10952590 DOI: 10.1111/tpj.16112] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 06/17/2023]
Abstract
Cross-linking of the cell-wall pectin domain rhamnogalacturonan-II (RG-II) via boron bridges between apiose residues is essential for normal plant growth and development, but little is known about its mechanism or reversibility. We characterized the making and breaking of boron bridges in vivo and in vitro at 'apoplastic' pH. RG-II (13-26 μm) was incubated in living Rosa cell cultures and cell-free media with and without 1.2 mm H3 BO3 and cationic chaperones (Ca2+ , Pb2+ , polyhistidine, or arabinogalactan-protein oligopeptides). The cross-linking status of RG-II was monitored electrophoretically. Dimeric RG-II was stable at pH 2.0-7.0 in vivo and in vitro. In-vitro dimerization required a 'catalytic' cation at all pHs tested (1.75-7.0); thus, merely neutralizing the negative charge of RG-II (at pH 1.75) does not enable boron bridging. Pb2+ (20-2500 μm) was highly effective at pH 1.75-4.0, but not 4.75-7.0. Cationic peptides were effective at approximately 1-30 μm; higher concentrations caused less dimerization, probably because two RG-IIs then rarely bonded to the same peptide molecule. Peptides were ineffective at pH 1.75, their pH optimum being 2.5-4.75. d-Apiose (>40 mm) blocked RG-II dimerization in vitro, but did not cleave existing boron bridges. Rosa cells did not take up d-[U-14 C]apiose; therefore, exogenous apiose would block only apoplastic RG-II dimerization in vivo. In conclusion, apoplastic pH neither broke boron bridges nor prevented their formation. Thus boron-starved cells cannot salvage boron from RG-II, and 'acid growth' is not achieved by pH-dependent monomerization of RG-II. Divalent metals and cationic peptides catalyse RG-II dimerization via co-ordinate and ionic bonding respectively (possible and impossible, respectively, at pH 1.75). Exogenous apiose may be useful to distinguish intra- and extra-protoplasmic dimerization.
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Affiliation(s)
- Rifat Ara Begum
- The Edinburgh Cell Wall GroupInstitute of Molecular Plant Sciences, The University of EdinburghDaniel Rutherford Building, The King's Buildings, Max Born CrescentEdinburghEH9 3BFUK
- Present address:
Department of Biochemistry and Molecular Biology, Faculty of Biological SciencesUniversity of DhakaCurzon HallDhaka1000Bangladesh
| | - David J. Messenger
- The Edinburgh Cell Wall GroupInstitute of Molecular Plant Sciences, The University of EdinburghDaniel Rutherford Building, The King's Buildings, Max Born CrescentEdinburghEH9 3BFUK
- Present address:
Unilever U.K. Central Resources LimitedColworth Science ParkSharnbrookMK44 1LQUK
| | - Stephen C. Fry
- The Edinburgh Cell Wall GroupInstitute of Molecular Plant Sciences, The University of EdinburghDaniel Rutherford Building, The King's Buildings, Max Born CrescentEdinburghEH9 3BFUK
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Begum RA, Fry SC. Boron bridging of rhamnogalacturonan-II in Rosa and arabidopsis cell cultures occurs mainly in the endo-membrane system and continues at a reduced rate after secretion. Ann Bot 2022; 130:703-715. [PMID: 36112021 PMCID: PMC9670748 DOI: 10.1093/aob/mcac119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Rhamnogalacturonan-II (RG-II) is a domain of primary cell-wall pectin. Pairs of RG-II domains are covalently cross-linked via borate diester bridges, necessary for normal cell growth. Interpreting the precise mechanism and roles of boron bridging is difficult because there are conflicting hypotheses as to whether bridging occurs mainly within the Golgi system, concurrently with secretion or within the cell wall. We therefore explored the kinetics of RG-II bridging. METHODS Cell-suspension cultures of Rosa and arabidopsis were pulse-radiolabelled with [14C]glucose, then the boron bridging status of newly synthesized [14C]RG-II domains was tracked by polyacrylamide gel electrophoresis of endo-polygalacturonase digests. KEY RESULTS Optimal culture ages for 14C-labelling were ~5 and ~1 d in Rosa and arabidopsis respectively. De-novo [14C]polysaccharide production occurred for the first ~90 min; thereafter the radiolabelled molecules were tracked as they 'aged' in the wall. Monomeric and (boron-bridged) dimeric [14C]RG-II domains appeared simultaneously, both being detectable within 4 min of [14C]glucose feeding, i.e. well before the secretion of newly synthesized [14C]polysaccharides into the apoplast at ~15-20 min. The [14C]dimer : [14C]monomer ratio of RG-II remained approximately constant from 4 to 120 min, indicating that boron bridging was occurring within the Golgi system during polysaccharide biosynthesis. However, [14C]dimers increased slightly over the following 15 h, indicating that limited boron bridging was continuing after secretion. CONCLUSIONS The results show where in the cell (and thus when in the 'career' of an RG-II domain) boron bridging occurs, helping to define the possible biological roles of RG-II dimerization and the probable localization of boron-donating glycoproteins or glycolipids.
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Affiliation(s)
- Rifat Ara Begum
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, The University of Edinburgh, Daniel Rutherford Building, The King’s Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Dhaka, Curzon Hall, Dhaka – 1000, Bangladesh
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Sanhueza D, Begum RA, Albenne C, Jamet E, Fry SC. An Arabidopsis thaliana arabinogalactan-protein (AGP31) and several cationic AGP fragments catalyse the boron bridging of rhamnogalacturonan-II. Biochem J 2022:BCJ20220340. [PMID: 36062804 DOI: 10.1042/BCJ20220340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/02/2022] [Accepted: 09/02/2022] [Indexed: 11/22/2022]
Abstract
Rhamnogalacturonan-II (RG-II) is a complex pectic domain in plant primary cell walls. In vivo, most RG-II domains are covalently dimerised via borate diester bridges, essential for correct cell-wall assembly, but the dimerisation of pure RG-II monomers by boric acid in vitro is extremely slow. Cationic ‘chaperones’ can promote dimerisation, probably by overcoming the mutual repulsion between neighbouring anionic RG-II molecules. Highly effective artificial chaperones include Pb2+ and polyhistidine, but the proposed natural chaperones remained elusive. We have now tested cationic peptide fragments of several Arabidopsis thaliana arabinogalactan-proteins (AGPs) as candidates. Fragments of AGP17, 18, 19 and 31 were effective, typically at ∼25 µg/ml (9–19 µM), promoting the boron bridging of 16–20 µM monomeric RG-II at pH 4.8 in vitro. Native AGP31 glycoprotein was also effective, and hexahistidine was moderately so. All chaperones tested interacted reversibly with RG-II and were not consumed during the reaction; thus they acted catalytically, and may constitute the first reported boron-acting enzyme activity, an RG-II borate diesterase. Many of the peptide chaperones became less effective catalysts at higher concentration, which we interpret as due to the formation of RG-II–peptide complexes with a net positive charge, as mutually repulsive as negatively charged pure RG-II molecules. The four unique AGPs studied here may serve an enzymic role in the living plant cell, acting on RG-II within Golgi cisternae and/or in the apoplast after secretion. In this way, RG-II and specific AGPs may contribute to cell-wall assembly and hence plant cell expansion and development.
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Zhao X, Ebert B, Zhang B, Liu H, Zhang Y, Zeng W, Rautengarten C, Li H, Chen X, Bacic A, Wang G, Men S, Zhou Y, Heazlewood JL, Wu AM. UDP-Api/UDP-Xyl synthases affect plant development by controlling the content of UDP-Api to regulate the RG-II-borate complex. Plant J 2020; 104:252-267. [PMID: 32662159 DOI: 10.1111/tpj.14921] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/08/2020] [Accepted: 07/01/2020] [Indexed: 05/14/2023]
Abstract
Rhamnogalacturonan-II (RG-II) is structurally the most complex glycan in higher plants, containing 13 different sugars and 21 distinct glycosidic linkages. Two monomeric RG-II molecules can form an RG-II-borate diester dimer through the two apiosyl (Api) residues of side chain A to regulate cross-linking of pectin in the cell wall. But the relationship of Api biosynthesis and RG-II dimer is still unclear. In this study we investigated the two homologous UDP-D-apiose/UDP-D-xylose synthases (AXSs) in Arabidopsis thaliana that synthesize UDP-D-apiose (UDP-Api). Both AXSs are ubiquitously expressed, while AXS2 has higher overall expression than AXS1 in the tissues analyzed. The homozygous axs double mutant is lethal, while heterozygous axs1/+ axs2 and axs1 axs2/+ mutants display intermediate phenotypes. The axs1/+ axs2 mutant plants are unable to set seed and die. By contrast, the axs1 axs2/+ mutant plants exhibit loss of shoot and root apical dominance. UDP-Api content in axs1 axs2/+ mutants is decreased by 83%. The cell wall of axs1 axs2/+ mutant plants is thicker and contains less RG-II-borate complex than wild-type Col-0 plants. Taken together, these results provide direct evidence of the importance of AXSs for UDP-Api and RG-II-borate complex formation in plant growth and development.
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Affiliation(s)
- Xianhai Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China
| | - Berit Ebert
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Baocai Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Huabin Liu
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Yutao Zhang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, The Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China
| | - Wei Zeng
- ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
- Sino-Australia Plant Cell Wall Research Centre, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, 311300, China
| | - Carsten Rautengarten
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Huiling Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China
| | - Xiaoyang Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China
| | - Antony Bacic
- ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
- Sino-Australia Plant Cell Wall Research Centre, State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, 311300, China
- Department of Animal, La Trobe Institute for Agriculture & Food, Plant & Soil Sciences, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Guodong Wang
- National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, The Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, 710119, China
| | - Shuzhen Men
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Joshua L Heazlewood
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ai-Min Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China
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Wimmer MA, Abreu I, Bell RW, Bienert MD, Brown PH, Dell B, Fujiwara T, Goldbach HE, Lehto T, Mock HP, von Wirén N, Bassil E, Bienert GP. Boron: an essential element for vascular plants: A comment on Lewis (2019) 'Boron: the essential element for vascular plants that never was'. New Phytol 2020; 226:1232-1237. [PMID: 31674046 DOI: 10.1111/nph.16127] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/09/2019] [Indexed: 06/10/2023]
Affiliation(s)
- Monika A Wimmer
- Department Quality of Plant Products, Institute of Crop Science, University of Hohenheim, 70599, Stuttgart, Germany
| | - Isidro Abreu
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), 28223, Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040, Madrid, Spain
| | - Richard W Bell
- Agriculture Discipline, College of Science, Health, Engineering and Education, Murdoch University, Perth, WA, 6150, Australia
| | - Manuela D Bienert
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466, Gatersleben, Germany
| | - Patrick H Brown
- Department of Plant Sciences, University of California-Davis, Davis, CA, 95616, USA
| | - Bernard Dell
- Agriculture Discipline, College of Science, Health, Engineering and Education, Murdoch University, Perth, WA, 6150, Australia
| | - Toru Fujiwara
- Department of Applied Biological Chemistry, The University of Tokyo, Tokyo, 113-8657, Japan
| | - Heiner E Goldbach
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53115, Bonn, Germany
| | - Tarja Lehto
- School of Forest Sciences, University of Eastern Finland, 80110, Joensuu, Finland
| | - Hans-Peter Mock
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466, Gatersleben, Germany
| | - Nicolaus von Wirén
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466, Gatersleben, Germany
| | - Elias Bassil
- Horticultural Sciences Department and Tropical Research and Education Center, University of Florida, Homestead, FL, 33031, USA
| | - Gerd P Bienert
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466, Gatersleben, Germany
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Mounet-Gilbert L, Dumont M, Ferrand C, Bournonville C, Monier A, Jorly J, Lemaire-Chamley M, Mori K, Atienza I, Hernould M, Stevens R, Lehner A, Mollet JC, Rothan C, Lerouge P, Baldet P. Two tomato GDP-D-mannose epimerase isoforms involved in ascorbate biosynthesis play specific roles in cell wall biosynthesis and development. J Exp Bot 2016; 67:4767-77. [PMID: 27382114 PMCID: PMC4973747 DOI: 10.1093/jxb/erw260] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
GDP-D-mannose epimerase (GME, EC 5.1.3.18) converts GDP-D-mannose to GDP-L-galactose, and is considered to be a central enzyme connecting the major ascorbate biosynthesis pathway to primary cell wall metabolism in higher plants. Our previous work demonstrated that GME is crucial for both ascorbate and cell wall biosynthesis in tomato. The aim of the present study was to investigate the respective role in ascorbate and cell wall biosynthesis of the two SlGME genes present in tomato by targeting each of them through an RNAi-silencing approach. Taken individually SlGME1 and SlGME2 allowed normal ascorbate accumulation in the leaf and fruits, thus suggesting the same function regarding ascorbate. However, SlGME1 and SlGME2 were shown to play distinct roles in cell wall biosynthesis, depending on the tissue considered. The RNAi-SlGME1 plants harbored small and poorly seeded fruits resulting from alterations of pollen development and of pollination process. In contrast, the RNAi-SlGME2 plants exhibited vegetative growth delay while fruits remained unaffected. Analysis of SlGME1- and SlGME2-silenced seeds and seedlings further showed that the dimerization state of pectin rhamnogalacturonan-II (RG-II) was altered only in the RNAi-SlGME2 lines. Taken together with the preferential expression of each SlGME gene in different tomato tissues, these results suggest sub-functionalization of SlGME1 and SlGME2 and their specialization for cell wall biosynthesis in specific tomato tissues.
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Affiliation(s)
- Louise Mounet-Gilbert
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Marie Dumont
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Carine Ferrand
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Céline Bournonville
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Antoine Monier
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Joana Jorly
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Martine Lemaire-Chamley
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Kentaro Mori
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Isabelle Atienza
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Michel Hernould
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Rebecca Stevens
- Institut National de la Recherche Agronomique (INRA), Unité de Recherche 1052 Génétique et Amélioration des Fruits et Légumes, Domaine Saint Maurice, 67, Allée des Chênes, CS 60094 F-84143 Montfavet Cedex, France
| | - Arnaud Lehner
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Jean Claude Mollet
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Christophe Rothan
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Patrice Lerouge
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Pierre Baldet
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
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Dumont M, Lehner A, Vauzeilles B, Malassis J, Marchant A, Smyth K, Linclau B, Baron A, Mas Pons J, Anderson CT, Schapman D, Galas L, Mollet JC, Lerouge P. Plant cell wall imaging by metabolic click-mediated labelling of rhamnogalacturonan II using azido 3-deoxy-D-manno-oct-2-ulosonic acid. Plant J 2016; 85:437-47. [PMID: 26676799 DOI: 10.1111/tpj.13104] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 11/23/2015] [Accepted: 11/27/2015] [Indexed: 05/10/2023]
Abstract
In plants, 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) is a monosaccharide that is only found in the cell wall pectin, rhamnogalacturonan-II (RG-II). Incubation of 4-day-old light-grown Arabidopsis seedlings or tobacco BY-2 cells with 8-azido 8-deoxy Kdo (Kdo-N3 ) followed by coupling to an alkyne-containing fluorescent probe resulted in the specific in muro labelling of RG-II through a copper-catalysed azide-alkyne cycloaddition reaction. CMP-Kdo synthetase inhibition and competition assays showing that Kdo and D-Ara, a precursor of Kdo, but not L-Ara, inhibit incorporation of Kdo-N3 demonstrated that incorporation of Kdo-N3 occurs in RG-II through the endogenous biosynthetic machinery of the cell. Co-localisation of Kdo-N3 labelling with the cellulose-binding dye calcofluor white demonstrated that RG-II exists throughout the primary cell wall. Additionally, after incubating plants with Kdo-N3 and an alkynated derivative of L-fucose that incorporates into rhamnogalacturonan I, co-localised fluorescence was observed in the cell wall in the elongation zone of the root. Finally, pulse labelling experiments demonstrated that metabolic click-mediated labelling with Kdo-N3 provides an efficient method to study the synthesis and redistribution of RG-II during root growth.
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Affiliation(s)
- Marie Dumont
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Arnaud Lehner
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Boris Vauzeilles
- Institut de Chimie des Substances Naturelles (ICSN) UPR CNRS 2301, 91198, Gif-sur-Yvette, France
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) UMR CNRS 8182, Université de Paris Sud, 91405, Orsay, France
- Click4Tag, Zone Luminy Biotech, Case 922, 163 Avenue de Luminy, 13009, Marseille, France
| | - Julien Malassis
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Alan Marchant
- Centre for Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Kevin Smyth
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Bruno Linclau
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Aurélie Baron
- Institut de Chimie des Substances Naturelles (ICSN) UPR CNRS 2301, 91198, Gif-sur-Yvette, France
| | - Jordi Mas Pons
- Institut de Chimie des Substances Naturelles (ICSN) UPR CNRS 2301, 91198, Gif-sur-Yvette, France
| | - Charles T Anderson
- Department of Biology and Center for Lignocellulose Structure and Formation, The Pennsylvania State University, University Park, PA, USA
| | - Damien Schapman
- PRIMACEN, IRIB, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Ludovic Galas
- PRIMACEN, IRIB, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Jean-Claude Mollet
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Patrice Lerouge
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV), EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
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Dumont M, Lehner A, Bardor M, Burel C, Vauzeilles B, Lerouxel O, Anderson CT, Mollet JC, Lerouge P. Inhibition of fucosylation of cell wall components by 2-fluoro 2-deoxy-L-fucose induces defects in root cell elongation. Plant J 2015; 84:1137-51. [PMID: 26565655 DOI: 10.1111/tpj.13071] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 10/26/2015] [Accepted: 11/03/2015] [Indexed: 05/21/2023]
Abstract
Screening of commercially available fluoro monosaccharides as putative growth inhibitors in Arabidopsis thaliana revealed that 2-fluoro 2-l-fucose (2F-Fuc) reduces root growth at micromolar concentrations. The inability of 2F-Fuc to affect an Atfkgp mutant that is defective in the fucose salvage pathway indicates that 2F-Fuc must be converted to its cognate GDP nucleotide sugar in order to inhibit root growth. Chemical analysis of cell wall polysaccharides and glycoproteins demonstrated that fucosylation of xyloglucans and of N-linked glycans is fully inhibited by 10 μm 2F-Fuc in Arabidopsis seedling roots, but genetic evidence indicates that these alterations are not responsible for the inhibition of root development by 2F-Fuc. Inhibition of fucosylation of cell wall polysaccharides also affected pectic rhamnogalacturonan-II (RG-II). At low concentrations, 2F-Fuc induced a decrease in RG-II dimerization. Both RG-II dimerization and root growth were partially restored in 2F-Fuc-treated seedlings by addition of boric acid, suggesting that the growth phenotype caused by 2F-Fuc was due to a deficiency of RG-II dimerization. Closer investigation of the 2F-Fuc-induced growth phenotype demonstrated that cell division is not affected by 2F-Fuc treatments. In contrast, the inhibitor suppressed elongation of root cells and promoted the emergence of adventitious roots. This study further emphasizes the importance of RG-II in cell elongation and the utility of glycosyltransferase inhibitors as new tools for studying the functions of cell wall polysaccharides in plant development. Moreover, supplementation experiments with borate suggest that the function of boron in plants might not be restricted to RG-II cross-linking, but that it might also be a signal molecule in the cell wall integrity-sensing mechanism.
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Affiliation(s)
- Marie Dumont
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Arnaud Lehner
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Muriel Bardor
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Carole Burel
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Boris Vauzeilles
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) UMR CNRS 8182, Université de Paris Sud, 91405, Orsay, France
- Institut de Chimie des Substances Naturelles (ICSN) UPR CNRS 2301, 91198, Gif-sur-Yvette, France
- Click4Tag, Zone Luminy Biotech, Case 922, 163 Avenue de Luminy, 13009, Marseille, France
| | - Olivier Lerouxel
- Centre de Recherches sur les Macromolécules Végétales (CERMAV) - CNRS BP 53, 38041, Grenoble Cedex 9, France
| | - Charles T Anderson
- Department of Biology and Center for Lignocellulose Structure and Formation, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Jean-Claude Mollet
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
| | - Patrice Lerouge
- Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA 4358, IRIB, VASI, Normandie Université, 76821, Mont-Saint-Aignan, France
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Abstract
In the present review, we describe current knowledge about synthesis of borate crosslinked rhamnogalacturonan II (RG-II) and it physiological roles. RG-II is a portion of pectic polysaccharide with high complexity, present in primary cell wall. It is composed of homogalacturonan backbone and four distinct side chains (A-D). Borate forms ester bonds with the apiosyl residues of side chain A of two RG-II monomers to generate borate dimerized RG-II, contributing for the formation of networks of pectic polysaccharides. In plant cell walls, more than 90% of RG-II are dimerized by borate under boron (B) sufficient conditions. Borate crosslinking of RG-II in primary cell walls, to our knowledge, is the only experimentally proven molecular function of B, an essential trace-element. Although abundance of RG-II and B is quite small in cell wall polysaccharides, increasing evidence supports that RG-II and its borate crosslinking are critical for plant growth and development. Significant advancement was made recently on the location and the mechanisms of RG-II synthesis and borate cross-linking. Molecular genetic studies have successfully identified key enzymes for RG-II synthesis and regulators including B transporters required for efficient formation of RG-II crosslinking and consequent normal plant growth. The present article focuses recent advances on (i) RG-II polysaccharide synthesis, (ii) occurrence of borate crosslinking and (iii) B transport for borate supply to RG-II. Molecular mechanisms underlying formation of borate RG-II crosslinking and the physiological impacts are discussed.
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Affiliation(s)
- Hiroya Funakawa
- Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
| | - Kyoko Miwa
- Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Japan
- *Correspondence: Kyoko Miwa, Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, North-10, West-5, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
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10
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Chormova D, Messenger DJ, Fry SC. Boron bridging of rhamnogalacturonan-II, monitored by gel electrophoresis, occurs during polysaccharide synthesis and secretion but not post-secretion. Plant J 2014; 77:534-46. [PMID: 24320597 PMCID: PMC4171739 DOI: 10.1111/tpj.12403] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 11/20/2013] [Accepted: 11/28/2013] [Indexed: 05/02/2023]
Abstract
The cell-wall pectic domain rhamnogalacturonan-II (RG-II) is cross-linked via borate diester bridges, which influence the expansion, thickness and porosity of the wall. Previously, little was known about the mechanism or subcellular site of this cross-linking. Using polyacrylamide gel electrophoresis (PAGE) to separate monomeric from dimeric (boron-bridged) RG-II, we confirmed that Pb(2+) promotes H3 BO3 -dependent dimerisation in vitro. H3 BO3 concentrations as high as 50 mm did not prevent cross-linking. For in-vivo experiments, we successfully cultured 'Paul's Scarlet' rose (Rosa sp.) cells in boron-free medium: their wall-bound pectin contained monomeric RG-II domains but no detectable dimers. Thus pectins containing RG-II domains can be held in the wall other than via boron bridges. Re-addition of H3 BO3 to 3.3 μm triggered a gradual appearance of RG-II dimer over 24 h but without detectable loss of existing monomers, suggesting that only newly synthesised RG-II was amenable to boron bridging. In agreement with this, Rosa cultures whose polysaccharide biosynthetic machinery had been compromised (by carbon starvation, respiratory inhibitors, anaerobiosis, freezing or boiling) lost the ability to generate RG-II dimers. We conclude that RG-II normally becomes boron-bridged during synthesis or secretion but not post-secretion. Supporting this conclusion, exogenous [(3) H]RG-II was neither dimerised in the medium nor cross-linked to existing wall-associated RG-II domains when added to Rosa cultures. In conclusion, in cultured Rosa cells RG-II domains have a brief window of opportunity for boron-bridging intraprotoplasmically or during secretion, but secretion into the apoplast is a point of no return beyond which additional boron-bridging does not readily occur.
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11
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Chormova D, Messenger DJ, Fry SC. Rhamnogalacturonan-II cross-linking of plant pectins via boron bridges occurs during polysaccharide synthesis and/or secretion. Plant Signal Behav 2014; 9:e28169. [PMID: 24603547 PMCID: PMC4091542 DOI: 10.4161/psb.28169] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Rhamnogalacturonan-II (RG-II), a domain of plant cell wall pectins, is able to cross-link with other RG-II domains through borate diester bridges. Although it is known to affect mechanical properties of the cell wall, the biochemical requirements and lifecycle of this cross-linking remain unclear. We developed a PAGE methodology to allow separation of monomeric and dimeric RG-II and used this to study the dynamics of cross-linking in vitro and in vivo. Rosa cells grown in medium with no added boron contained no RG-II dimers, although these re-appeared after addition of boron to the medium. However, other Rosa cultures which were unable to synthesize new polysaccharides did not show dimer formation. We conclude that RG-II normally becomes cross-linked intraprotoplasmically or during secretion, but not post-secretion.
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