Stephen C Fry, The University of Edinburgh, Edinburgh, UK
Published online: April 2001
DOI: 10.1038/npg.els.0001683
Most plant cell wall polymers are synthesized from ‘activated’ precursors by the action of transferases. These enzymes are located in cell membranes (synthesizing polysaccharides and glycoproteins) or in the cell wall itself (synthesizing cutin and suberin). Lignin, in contrast, is synthesized in the wall by oxidative rather than transferase-catalysed reactions.
Keywords: cell wall polymer assembly; polysaccharides (plant); Golgi bodies; nucleoside diphosphate sugars; lignin
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Figure 1. Major pathways for the synthesis and interconversion of the NDP sugars used in the biosynthesis of plant cell wall polysaccharides. Some indication of the relative flux through the various pathways is given by arrow thickness. In addition, solid arrows indicate primary pathways for de novo synthesis of NDP sugars and inositol. Pecked arrows (------) imply great variation between tissues. Dot-dashed arrows (–×–×–×) indicate scavenger pathways involved in recycling monosaccharides, e.g. released by polysaccharide turnover. The ‘box’ is the pool of hexose monophosphates mentioned in the text. Reactions marked * are isomerizations, with no other reactants. Numbered enzymes are: 1, phosphoglucomutase; 2, glucose 6-phosphate isomerase; 3, mannose 6-phosphate isomerase; 4, phosphomannomutase; 5, UDP-glucose pyrophosphorylase; 6, GDP-mannose pyrophosphorylase; 7, myo-inositol 1-phosphate synthase; 8, myo-inositol 1-phosphatase; 9, myo-inositol oxygenase; 10, glucuronokinase; 11, UDP-glucuronate pyrophosphorylase; 12, UDP-glucose dehydrogenase; 13, UDP-glucuronate decarboxylase; 14, UDP-glucose 4-epimerase; 15, UDP-glucuronate 4-epimerase; 16, UDP-xylose 4-epimerase; 17, ‘GDP-fucose synthase’ (three individual activities: (a) GDP-d-mannose 4,6-dehydratase, (b) GDP-4-keto-6-deoxy-d-mannose 3,5-epimerase, and (c) GDP-4-keto-l-fucose 4-reductase); 18, GDP-mannose 3,5-epimerase; 19, ‘UDP-rhamnose synthase’ (probably three activities, cf. 17); 20, UDP-apiose synthase; 21, d-galactokinase; 22, galacturonokinase; 23, arabinokinase; 24, fucokinase; 25, hexokinase or glucokinase; 26, fructokinase; 27, mannokinase; 28, UDP-d-galactose pyrophosphorylase; 29, UDP-galacturonate pyrophosphorylase; 30, UDP-arabinose pyrophosphorylase; 31, GDP-fucose pyrophosphorylase.
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Figure 2. Early steps in lignin synthesis. Coniferyl alcohol (one of three monolignols) is oxidized enzymically, losing one hydrogen atom to form a free radical, which rapidly interconverts between four tautomers (A, B, C, D). These pair off nonenzymically to form dimers (two of the several possible dimers are illustrated), some of which (e.g. the D + D dimer) undergo intramolecular substitution reactions to form more stable products.
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| References | |
| Arioli T, Peng L, Betzner AS et al. (1998) Molecular analysis of cellulose biosynthesis in Arabidopsis. Science 279: 717–720. | |
| Bolwell GP and Northcote DH (1981) Control of hemicellulose and pectin synthesis during differentiation of vascular tissue in bean (Phaseolus vulgaris) callus and in bean hypocotyl. Planta 152: 225–233. | |
| Croteau R and Kolattukudy PE (1974) Biosynthesis of hydroxy fatty acid polymers. Enzymatic synthesis of cutin from monomer acids by cell-free preparations from the epidermis of Vicia faba leaves. Biochemistry 13: 3193–3202. | |
| Davin LB, Wang H-B, Crowell AL et al. (1997) Stereoselective bimolecular phenoxy radical coupling by an auxiliary (dirigent) protein without an active center. Science 275: 362–366. | |
| Hobbs MC, Delarge MHP, Baydoun EA-H and Brett CT (1991) Differential distribution of a glucuronyltransferase, involved in glucuronoxylan synthesis, within the Golgi apparatus of pea (Pisum sativum var. Alaska). Biochemical Journal 277: 653–658. | |
| Pear JR, Kawagoe Y, Schreckengost WE, Delmer DP and Stalker DM (1996) Higher plants contain homologs of the bacterial celA genes encoding the catalytic subunit of cellulose synthase. Proceedings of the National Academy of Sciences of the USA 93: 12637–12642. | |
| Reid JSG, Edwards M, Gidley MJ and Clark AH (1995) Enzyme specificity in galactomannan biosynthesis. Planta 195: 489–495. | |
| Sadava D and Chrispeels MJ (1971) Intracellular site of proline hydroxylation in plant cells. Biochemistry 10: 4290–4294. | |
|
Thompson JE,
Smith RC and
Fry SC
(1997)
Xyloglucan undergoes inter-polymeric transglycosylation during binding to the plant cell wall in vivo: evidence from | |
| Zhang GF and Staehelin LA (1992) Functional compartmentation of the Golgi-apparatus of plant-cells – immunocytochemical analysis of high-pressure frozen-substituted and freeze-substituted sycamore maple suspension-culture cells. Plant Physiology 99: 1070–1083. | |
| Further Reading | |
| Bolwell GP (1988) Synthesis of cell wall components: aspects of control. Phytochemistry 27: 1235–1253. | |
| Boudet AM, Lapierre C and Grima-Pettanati J (1995) Biochemistry and molecular biology of lignification. New Phytologist 129: 203–236. | |
| Delmer DP and Amor Y (1995) Cellulose biosynthesis. Plant Cell 7: 987–1000. | |
| book Delmer DP and Stone BA (1988) "Biosynthesis of plant cell walls". In: Preiss J (ed.) Biochemistry of Plants: a Comprehensive Treatise, vol. 14, pp. 373–419. New York: Academic Press. | |
| book Feingold DS and Barber GA (1990) "Nucleotide sugars". In: Dey PM (ed.) Methods in Plant Biochemistry, vol. 2, pp. 39–78. London: Academic Press. | |
| book Fry SC (1988) The Growing Plant Cell Wall: Chemical and Metabolic Analysis. Harlow, Essex: Longman. | |
| book Kolattukudy PE (1996) "Biosynthetic pathways of cutin and waxes, and their sensitivity to environmental stresses". In: Kerstiens G (ed.) Plant Cuticles – An Integrated and Functional Approach, pp. 83–108. Oxford: Bios. | |
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