Taxonomic group: plant / Streptophyta
(Phylum: Streptophyta)
Organ / tissue: stem
The structure was elucidated in this paperPublication DOI: 10.1105/tpc.105.035501Journal NLM ID: 9208688Publisher: Rockville, MD: American Society of Plant Physiologists
Correspondence: will
ccrc.uga.edu
Institutions: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA, Department of Plant Biology, University of Georgia, Athens, GA, USA, Daniel B. Warnell School of Forest Resources, University of Georgia, Athens, GA, USA, Richard B. Russell Agriculture Research Center, U.S. Department of Agriculture, Agricultural Research Service, Athens, Georgia 30604
Secondary walls in vessels and fibers of dicotyledonous plants are mainly composed of cellulose, xylan, and lignin. Although genes involved in biosynthesis of cellulose and lignin have been intensively studied, little is known about genes participating in xylan synthesis. We found that Arabidopsis thaliana fragile fiber8 (fra8) is defective in xylan synthesis. The fra8 mutation caused a dramatic reduction in fiber wall thickness and a decrease in stem strength. FRA8 was found to encode a member of glycosyltransferase family 47 and exhibits high sequence similarity to tobacco (Nicotiana plumbaginifolia) pectin glucuronyltransferase. FRA8 is expressed specifically in developing vessels and fiber cells, and FRA8 is targeted to Golgi. Comparative analyses of cell wall polysaccharide fractions from fra8 and wild-type stems showed that the xylan and cellulose contents are drastically reduced in fra8, whereas xyloglucan and pectin are elevated. Further structural analysis of cell walls revealed that although wild-type xylans contain both glucuronic acid and 4-O-methylglucuronic acid residues, xylans from fra8 retain only 4-O-methylglucuronic acid, indicating that the fra8 mutation results in a specific defect in the addition of glucuronic acid residues onto xylans. These findings suggest that FRA8 is a glucuronyltransferase involved in the biosynthesis of glucuronoxylan during secondary wall formation.
Structure type: oligomer ; 745
Location inside paper: Figure 9A
Trivial name: X4G, X4U/X4G
Contained glycoepitopes: IEDB_114701,IEDB_115136,IEDB_140630,IEDB_167188,IEDB_174332
Methods: 1H NMR, GC-EI-MS, biological assays, enzymatic digestion, enzymatic assay, TEM, MALDI-TOF-MS, genetic manipulations
Enzymes that release or process the structure: FRA8
Related record ID(s): 61073, 61074, 61075, 61076, 61077
NCBI Taxonomy refs (TaxIDs): 3702Reference(s) to other database(s): GTC:G65832ST
Show glycosyltransferases
There is only one chemically distinct structure:
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