TY  - JOUR
AU  - Voiniciuc, Catalin
AU  - Schmidt, Maximilian Heinrich-Wilhelm
AU  - Berger, Adeline
AU  - Yang, Bo
AU  - Ebert, Berit
AU  - Scheller, Henrik Vibe
AU  - North, Helen M.
AU  - Usadel, Björn
AU  - Günl, Markus
TI  - MUCI10 Produces Galactoglucomannan That Maintains Pectin and Cellulose Architecture in Arabidopsis Seed Mucilage
JO  - Plant physiology
VL  - 169
IS  - 1
SN  - 1532-2548
CY  - Rockville, Md.
PB  - Soc.
M1  - FZJ-2015-05202
SP  - pp.00851.2015 -
PY  - 2015
AB  - Plants invest a lot of their resources into the production of an extracellular matrix built of polysaccharides. While the composition of the cell wall is relatively well characterized, the functions of the individual polymers and the enzymes that catalyze their biosynthesis remain poorly understood. We exploited the Arabidopsis thaliana seed coat epidermis (SCE) to study cell wall synthesis. SCE cells produce mucilage, a specialized secondary wall that is rich in pectin, at a precise stage of development. A co-expression search for MUCILAGE-RELATED (MUCI) genes identified MUCI10 as a key determinant of mucilage properties. MUCI10, a member of the GT34 family, is closely related to a fenugreek enzyme that has in vitro galactomannan α-1,6-galactosyltransferase activity. Our detailed analysis of the muci10 mutants demonstrates that mucilage contains highly branched galactoglucomannan (GGM) rather than unbranched glucomannan. MUCI10 likely decorates glucomannan, synthesized by CSLA2, with galactose residues in vivo. The degree of galactosylation is essential for the synthesis of the GGM backbone, the structure of cellulose, mucilage density, as well as the adherence of pectin. We propose that GGM scaffolds control mucilage architecture along with cellulosic rays, and show that Arabidopsis SCE cells represent an excellent model to study the synthesis and function of GGM. Arabidopsis natural varieties with defects similar to muci10 mutants may reveal additional genes involved in GGM synthesis. Since GGM is the most abundant hemicellulose in the secondary walls of gymnosperms, understanding its biosynthesis may facilitate improvements in the production of valuable commodities from softwoods.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000360930600033
C6  - pmid:26220953
DO  - DOI:10.1104/pp.15.00851
UR  - https://juser.fz-juelich.de/record/203204
ER  -