Abstract
O-Acetylglucuronoxylans (AcGX) in Arabidopsis thaliana
carry acetyl residues on the 2-O and/or 3-O positions of
the xylopyranosyl (Xylp) units, but the distribution of
different O-acetylated Xylp units is partly unclear. We
studied a possible correlation of xylan acetylation and
the activities of different glycosyltransferases involved
in xylan biosynthesis by analyzing the distribution of
O-acetyl substituents on AcGX from Arabidopsis wild-type
and mutants irx7, irx9-1, irx10, irx14 and gux1gux2. The
relative contents of the Xylp structural units were
determined with quantitative two-dimensional
heteronuclear single quantum coherence nuclear magnetic
resonance spectroscopy. In the wild type, the degree of
acetylation (DA) was 60%. Mono-and diacetylated Xylp
units constituted 44 and 6% of the AcGX backbone,
respectively; while (4-O-methyl)-glucopyranosyluronic
acid (1?2)-linked Xylp units, most of which also carry
3-Oacetylation, represented 13%. The DA was decreased in
irx7, irx9-1 and irx14 due to the decrease in
monoacetylation (2-O and 3-O), indicating a relationship
between acetylation and other AcGX biosynthetic
processes. The possible interactions that could lead to
such changes have been discussed. No change in DAwas
observed in irx10 and gux1gux2, but monoacetylation was
nonetheless elevated in gux1gux2. This indicates that
acetylation occurs after addition of GlcpA to the xylan
backbone. Mass fragmentation analysis suggests that the
prevalent acetylation pattern is the acetyl group added
on every other Xylp unit
Original language | English |
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Pages (from-to) | 494-506 |
Number of pages | 12 |
Journal | Glycobiology |
Volume | 24 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2014 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Arabidopsis
- GlucUronic acid substitution of xylan (GUX)
- irregular xylem
- secondary wall
- xylan acetylation