Arabidopsis genes IRREGULAR XYLEM (IRX15)and IRX 15L encode DUF579 containing proteins that are essential for normal xylan deposition in the secondary cell wall.

Simon John McQueen Mason, D Brown, R. Wightman, Z. Zhang, T. Tryfona, P. Dupree, S. Turner, Leonardo Dario Gomez

Research output: Contribution to journalArticlepeer-review


irx15l double mutants are disorganized, compared with the wild type or other previously described xylan mutants, and exhibit dramatic increases in the quant 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 irx15ity 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.
Original languageEnglish
Pages (from-to)401-413
JournalPlant Journal
Publication statusPublished - 2011

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