These authors contributed equally to this work.
Arabidopsis genes IRREGULAR XYLEM (IRX15) and IRX15L encode DUF579-containing proteins that are essential for normal xylan deposition in the secondary cell wall
Article first published online: 24 FEB 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 66, Issue 3, pages 401–413, May 2011
How to Cite
Brown, D., Wightman, R., Zhang, Z., Gomez, L. D., Atanassov, I., Bukowski, J.-P., Tryfona, T., McQueen-Mason, S. J., Dupree, P. and Turner, S. (2011), Arabidopsis genes IRREGULAR XYLEM (IRX15) and IRX15L encode DUF579-containing proteins that are essential for normal xylan deposition in the secondary cell wall. The Plant Journal, 66: 401–413. doi: 10.1111/j.1365-313X.2011.04501.x
- Issue published online: 26 APR 2011
- Article first published online: 24 FEB 2011
- Accepted manuscript online: 19 JAN 2011 11:30AM EST
- Received 22 August 2010; revised 18 December 2010; accepted 12 January 2011.
- secondary cell wall;
There are 10 genes in the Arabidopsis genome that contain a domain described in the Pfam database as domain of unknown function 579 (DUF579). Although DUF579 is widely distributed in eukaryotic species, there is no direct experimental evidence to assign a function to it. Five of the 10 Arabidopsis DUF579 family members are co-expressed with marker genes for secondary cell wall formation. Plants in which two closely related members of the DUF579 family have been disrupted by T-DNA insertions contain less xylose in the secondary cell wall as a result of decreased xylan content, and exhibit mildly distorted xylem vessels. Consequently we have named these genes IRREGULAR XYLEM 15 (IRX15) and IRX15L. These mutant plants exhibit many features of previously described xylan synthesis mutants, such as the replacement of glucuronic acid side chains with methylglucuronic acid side chains. By contrast, immunostaining of xylan and transmission electron microscopy (TEM) reveals that the walls of these irx15 irx15l double mutants are disorganized, compared with the wild type or other previously described xylan mutants, and exhibit dramatic increases in the quantity of sugar released in cell wall digestibility assays. Furthermore, localization studies using fluorescent fusion proteins label both the Golgi and also an unknown intracellular compartment. These data are consistent with irx15 and irx15l defining a new class of genes involved in xylan biosynthesis. How these genes function during xylan biosynthesis and deposition is discussed.