Taxonomic group: plant / Streptophyta
(Phylum: Streptophyta)
The structure was elucidated in this paperPublication DOI: 10.1104/pp.110.155309Journal NLM ID: 0401224Publisher: American Society of Plant Biologists
Correspondence: zhye
plantbio.uga.edu
Institutions: Department of Plant Biology, University of Georgia, Athens, GA, USA, National Exposure Research Laboratory, United States Environmental Protection Agency, Athens, Georgia 30605
There exist four members of family GT43 glycosyltransferases in the Arabidopsis (Arabidopsis thaliana) genome, and mutations of two of them, IRX9 and IRX14, have previously been shown to cause a defect in glucuronoxylan (GX) biosynthesis. However, it is currently unknown whether IRX9 and IRX14 perform the same biochemical function and whether the other two GT43 members are also involved in GX biosynthesis. In this report, we performed comprehensive genetic analysis of the functional roles of the four Arabidopsis GT43 members in GX biosynthesis. The I9H (IRX9 homolog) and I14H (IRX14 homolog) genes were shown to be specifically expressed in cells undergoing secondary wall thickening, and their encoded proteins were targeted to the Golgi, where GX is synthesized. Overexpression of I9H but not IRX14 or I14H rescued the GX defects conferred by the irx9 mutation, whereas overexpression of I14H but not IRX9 or I9H complemented the GX defects caused by the irx14 mutation. Double mutant analyses revealed that I9H functioned redundantly with IRX9 and that I14H was redundant with IRX14 in their functions. In addition, double mutations of IRX9 and IRX14 were shown to cause a loss of secondary wall thickening in fibers and a much more severe reduction in GX amount than their single mutants. Together, these results provide genetic evidence demonstrating that all four Arabidopsis GT43 members are involved in GX biosynthesis and suggest that they form two functionally nonredundant groups essential for the normal elongation of GX backbone.
Structure type: oligomer ; 745
Location inside paper: Figure 5
Trivial name: X4G, X4U/X4G
Contained glycoepitopes: IEDB_114701,IEDB_115136,IEDB_140630,IEDB_167188,IEDB_174332
Methods: 1H NMR, GLC, biological assays, enzymatic assay, MALDI-TOF-MS, genetic manipulations
Enzymes that release or process the structure: IRX9, IRX14
Related record ID(s): 61081
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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