Premium
Characterization of IRX10 and IRX10‐like reveals an essential role in glucuronoxylan biosynthesis in Arabidopsis
Author(s) -
Brown David M.,
Zhang Zhig,
Stephens Elaine,
Dupree Paul,
Turner Simon R.
Publication year - 2009
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2008.03729.x
Subject(s) - arabidopsis , characterization (materials science) , biosynthesis , chemistry , biochemistry , gene , nanotechnology , mutant , materials science
Summary Xylan, the major hemicellulosic polysaccharide in Arabidopsis secondary cell walls, requires a number of glycosyltransferases (GT) to catalyse formation of the various glycosidic linkages found in the polymer. In this study, we characterized IRX10 and IRX10‐like ( IRX10‐L ), two highly homologous genes encoding members of the glycosyltransferase family 47 (GT47). T‐DNA insertions in IRX10 gave a mild irregular xylem (irx) phenotype consistent with a minor defect in secondary cell‐wall synthesis, whereas plants containing mutations in IRX10‐L showed no change. However, irx10 irx10‐L double mutant plants showed a much more severe irx and whole‐plant phenotype, suggesting considerable functional redundancy between these two genes. Detailed biochemical analysis of the irx10 irx10‐L double mutant showed a large reduction of xylan in the secondary cell walls, consistent with a specific defect in xylan biosynthesis. Furthermore, the irx10 irx10‐L mutant retains the unique oligosaccharide found at the reducing end of Arabidopsis xylan, but shows a severe reduction in β(1,4) xylosyltransferase activity. These characteristics are similar to those of irx9 and irx14 , mutants that are believed to be defective in xylan chain elongation, and suggests that IRX10 and IRX10‐L also play a role in elongation of the xylan backbone.