1. The N-Glycan Cluster from Xanthomonas campestris pv. campestris: A toolbox for sequential plant n-glycan processing
- Author
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Dupoiron, Stéphanie, Zischek, Claudine, Ligat, Laetitia, Carbonne, Julien, Boulanger, Alice, Duge De Bernonville, Thomas, Lautier, Martine, RIVAL, Pauline, Arlat, Matthieu, Jamet, Elisabeth, Lauber, Emmanuelle, Albenne, Cécile, Laboratoire de Recherche en Sciences Végétales (LRSV), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire des interactions plantes micro-organismes (LIPM), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Interactions Microbiennes dans la Rhizosphère et les Racines, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Dynamique et Evolution des Parois cellulaires végétales
- Subjects
Enzyme Kinetics ,Xanthomonas ,Glycoside Hydrolases ,Bacteria ,N-Linked Glycosylation ,[SDV]Life Sciences [q-bio] ,Glycoside Hydrolase ,food and beverages ,Brassica ,Plant ,Xanthomonas campestris ,Carbohydrate Processing ,Phytopathogen ,Xylosidases ,Polysaccharides ,alpha-Mannosidase ,Enzymology ,bacteria ,Humans ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,hormones, hormone substitutes, and hormone antagonists ,Plant Diseases - Abstract
International audience; N-Glycans are widely distributed in living organisms but represent only a small fraction of the carbohydrates found in plants. This probably explains why they have not previously been considered as substrates exploited by phytopathogenic bacteria during plant infection. Xanthomonas campestris pv. campestris, the causal agent of black rot disease of Brassica plants, possesses a specific system for GlcNAc utilization expressed during host plant infection. This system encompasses a cluster of eight genes (nixE to nixL) encoding glycoside hydrolases (GHs). In this paper, we have characterized the enzymatic activities of these GHs and demonstrated their involvement in sequential degradation of a plant N-glycan using a N-glycopeptide containing two GlcNAcs, three mannoses, one fucose, and one xylose (N2M3FX) as a substrate. The removal of the α-1,3-mannose by the α-mannosidase NixK (GH92) is a prerequisite for the subsequent action of the β-xylosidase NixI (GH3), which is involved in the cleavage of the β-1,2-xylose, followed by the α-mannosidase NixJ (GH125), which removes the α-1,6-mannose. These data, combined to the subcellular localization of the enzymes, allowed us to propose a model of N-glycopeptide processing by X. campestris pv. campestris. This study constitutes the first evidence suggesting N-glycan degradation by a plant pathogen, a feature shared with human pathogenic bacteria. Plant N-glycans should therefore be included in the repertoire of molecules putatively metabolized by phytopathogenic bacteria during their life cycle.
- Published
- 2015