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Communication Dans Un Congrès Année : 2024

Rhamnogalacturonan II : an enigma in plant glycobiology

Résumé

The plant cell wall has for a long time been considered as a simple association of linear polysaccharides, such as cellulose and pectins, a polymer of galacturonic acid, acting as a rigid barrier around the plant cells. Then, it has been admitted that this cell wall might exhibit more sophisticated properties to in one hand resist to the turgor pressure and to in another hand allow fast and polarized cell elongation as reported for instance for pollen tubes (0.5 μm/s). In the eighties, the plant cell wall has received an increasing interest, notably with the discovery of rhamnogalacturonan-II (RG-II)1. RG-II is a 5 kDa oligosaccharide that is inserted in the pectin backbone. It is composed of 12 different glycosidic residues, as well as rare monosaccharides (Apiose, Kdo, Dha, aceric acid), arranged in four to six side-chains (see scheme below). Moreover, RG-II is dimerized in the cell wall by a borate diester between two apiose residues that leads to the cross-linking of two pectic chains2. This RG-II dimerization is crucial for the cell elongation process. Any mutation affecting the RG-II biosynthesis or its cross-linking deeply impairs the plant development3. Finally, all land plants contain 2-4% of highly structurally conserved RG-II in their cell walls. It is now widely admitted that RG-II appears with the colonization of lands by aquatic plants to ensure specific functions related to these new environmental growth conditions4. This presentation will tell the history of RG-II from its discovery to the current knowledge on its functions, including scientific contributions from my lab.
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Dates et versions

hal-04624964 , version 1 (25-06-2024)

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  • HAL Id : hal-04624964 , version 1

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Patrice Lerouge. Rhamnogalacturonan II : an enigma in plant glycobiology. 29ème Journées du Groupe Français des Glycosciences, May 2024, Obernai, France. ⟨hal-04624964⟩
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