Taxonomic group: plant / Streptophyta
(Phylum: Streptophyta)
Organ / tissue: stem
The structure was elucidated in this paperPublication DOI: 10.1093/pcp/pcp025Journal NLM ID: 9430925Publisher: Tokyo: Oxford University Press
Correspondence: zhye
plantbio.uga.edu
Institutions: Department of Plant Biology, University of Georgia, Athens, GA 30602, USA, National Exposure Research Laboratory, US Environmental Protection Agency, Athens, GA 30605, USA
The FRAGILE FIBER8 (FRA8) gene was previously shown to be required for the biosynthesis of the reducing end tetrasaccharide sequence of glucuronoxylan (GX) in Arabidopsis thaliana. Here, we demonstrate that F8H, a close homolog of FRA8, is a functional paralog of FRA8 involved in GX biosynthesis. The F8H gene is preferentially expressed in xylem cells, in which the secondary walls contain an abundant amount of GX, and the F8H protein is targeted to the Golgi where GX is synthesized. Overexpression of F8H in the fra8 mutant completely complemented the fra8 mutant phenotypes including the secondary wall thickness of fibers and vessels, vessel morphology, GX content and the abundance of the reducing end tetrasaccharide sequence of GX, indicating that F8H shares the same biochemical function as FRA8. Although the f8h mutant alone did not show any detectable cell wall defects, the f8h/fra8 double mutant exhibits an additional reduction in cell wall xylose level, a more severe deformation of vessels and an extreme retardation in plant growth compared with the fra8 mutant. Together, our findings suggest that F8H and FRA8 are functional paralogs and that they function redundantly in GX biosynthesis during secondary wall formation in the xylem.
glycosyltransferase, Arabidopsis, Xylan, glucuronoxylan biosynthesis, secondary wall biosynthesis
Structure type: oligomer ; 745
Location inside paper: Figure 8
Trivial name: X4G, X4U/X4G
Contained glycoepitopes: IEDB_114701,IEDB_115136,IEDB_140630,IEDB_167188,IEDB_174332
Methods: 1H NMR, GLC, MALDI-TOF MS, biological assays, enzymatic digestion, genetic manipulations
Enzymes that release or process the structure: F8H, FRA8
Related record ID(s): 61079, 61080
NCBI Taxonomy refs (TaxIDs): 3702Reference(s) to other database(s): GTC:G65832ST
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There is only one chemically distinct structure:
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