TY  - JOUR
A1  - Eckermann, Nora
A1  - Fettke, Jörg
A1  - Pauly, Markus
A1  - Bazant, Esther
A1  - Steup, Martin
T1  - Starch-metabolism related isozymes in higher plants
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Usadel, Björn
A1  - Kuschinsky, Anja M.
A1  - Rosso, Mario G.
A1  - Eckermann, Nora
A1  - Pauly, Markus
T1  - RHM2 is involved in mucilage pectin synthesis and is required for the development of the seed coat in Arabidopsis
N2  - Pectins are major components of primary plant cell walls and the seed mucilage of Arabidopsis. Despite progress in the structural elucidation of pectins, only very few enzymes participating in or regulating their synthesis have been identified. A first candidate gene involved-in the synthesis of pectinaceous rhamnogalacturonan I is RHM2, a putative plant ortholog to NDP-rhamnose biosynthetic enzymes in bacteria. Expression studies with a promoter beta-glucuronidase construct and reverse transcription PCR data show that RHM2 is expressed ubiquitously. Rhm2 T-DNA insertion mutant lines were identified using a reverse genetics approach. Analysis of the rhm2 seeds by various staining methods and chemical analysis of the mucilage revealed a strong reduction of rhamnogalacturonan I in the mucilage and a decrease of its molecular weight. In addition, scanning electron microscopy of the seed surface indicated a distorted testa morphology, illustrating not only a structural but also a developmental role for RGI or rhamnose metabolism in proper testa formation
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Fettke, Jörg
A1  - Poeste, Simon
A1  - Eckermann, Nora
A1  - Tiessen, Axel
A1  - Pauly, Markus
A1  - Geigenberger, Peter Ludwig
A1  - Steup, Martin
T1  - Analysis of cytosolic heteroglycans from leaves of transgenic potato (Solanum tuberosum L.) plants that under- or overexpress the Pho 2 phosphorylase isozyme
N2  - During starch degradation, chloroplasts export neutral sugars into the cytosol where they appear to enter a complex glycan metabolism. Interactions between glycans and glucosyl transferases residing in the cytosol were studied by analyzing transgenic potato (Solanum tuberosum L.) plants that possess either decreased or elevated levels of the cytosolic (Pho 2) phosphorylase isoform. Water-soluble heteroglycans (SHGs) were isolated from these plants and were characterized. SHG contains, as major constituents, arabinose, rhamnose, galactose and glucose. Non-aqueous fractionation combined with other separation techniques revealed a distinct pool of the SHG that is located in the cytosol. Under in vitro conditions, the cytosolic heteroglycans act as glucosyl acceptor selectively for Pho 2. Acceptor sites were characterized by a specific hydrolytic degradation following the Pho 2-catalyzed glucosyl transfer. The size distribution of the cytosolic SHG increased during the dark period, indicating a distinct metabolic activity related to net starch degradation. Antisense inhibition of Pho 2 resulted in increased glucosyl and rhamnosyl contents of the glycans. Overexpression of Pho 2 decreased the content of both residues. Compared with the wild type, in both types of transgenic plants the size of the cytosolic glycans was increased
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Obel, Nicolai
A1  - Usadel, Björn
A1  - Choo, Tze Siang
A1  - Pauly, Markus
T1  - Analysing cell wall biosynthesis to study its role in biotic and abiotic stress reactions
Y1  - 2004
SN  - 3-00-011587-0
ER  -