Poster: Lipids & Related Molecules

Abs # 871: The Role of Digalactosyldiacylglycerol for the Synthesis of the Peribacteroid Membrane in Legumes - are Plant Lipids Critical for Nodule Formation?

Presenter:	Gaude, Nicole , gaude@mpimp-golm.mpg.de
Authors	Gaude, Nicole  (A)   Doermann, Peter  (A)
Affiliations:	(A): Max Planck Institute for Molecular Plantphysiology, Golm, Germany

Nitrogen fixation in the root nodules of legumes is localized to Rhizobia bacteria which exist inside the cytosol of the plant cell, surrounded by a bacterial membrane and by a plant-derived, so-called peribacteroid membrane. By thin-layer chromatography, we could demonstrate that the galactolipid digalactosyldiacylglycerol (DGDG) is an abundant lipid in the peribacteroid membrane of soybean (Glycine max) and Lotus japonicus. This finding indicates that DGDG in higher plants is not restricted to plastids and corroborates previous experiments which showed that DGDG accumulates in extraplastidial membranes after phosphate deprivation. We analysed the fatty acid and the sugar composition of DGDG derived from the soybean peribacteroid membrane. Northern hybridizations indicated an induction of DGD1 and DGD2 gene expression in nodules as compared to roots. The goal of these experiments is to understand the biosynthesis and function of different polar lipids, in particular galactolipids, for the production of the peribacteroid membrane during nodulation.