title: The plant nitrogen mobilization promoted by Colletotrichum lindemuthianum in Phaseolus leaves depends on fungus pathogenicity.
abstract: Nitrogen plays an essential role in the nutrient relationship between plants and pathogens. Some studies report that the nitrogen-mobilizing plant metabolism that occurs during abiotic and biotic stress could be a 'slash-and-burn' defence strategy. In order to study nitrogen recycling and mobilization in host plants during pathogen attack and invasion, the Colletotrichum lindemuthianum/Phaseolus vulgaris interaction was used as a model. C. lindemuthianum is a hemibiotroph that causes anthracnose disease on P. vulgaris. Non-pathogenic mutants and the pathogenic wild-type strain were used to compare their effects on plant metabolism. The deleterious effects of infection were monitored by measuring changes in chlorophyll, protein, and amino acid concentrations. It was shown that amino acid composition changed depending on the plant-fungus interaction and that glutamine accumulated mainly in the leaves infected by the pathogenic strain. Glutamine accumulation correlated with the accumulation of cytosolic glutamine synthetase (GS1 alpha) mRNA. The most striking result was that the GS1 alpha gene was induced in all the fungus-infected leaves, independent of the strain used for inoculation, and that GS1 alpha expression paralleled the PAL3 and CHS defence gene expression. It is concluded that a role of GS1 alpha in plant defence has to be considered.
authors.affiliation: Unité de Nutrition Azotée des Plantes, UR 511, INRA, Route de Saint Cyr F-78000 Versailles, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Tavernier
authors.forename: Sandrine
authors.initials: S
authors.lastname: Cadiou
authors.forename: Karine
authors.initials: K
authors.lastname: Pageau
authors.forename: Richard
authors.initials: R
authors.lastname: Laugé
authors.forename: Michèle
authors.initials: M
authors.lastname: Reisdorf-Cren
authors.forename: Thierry
authors.initials: T
authors.lastname: Langin
authors.forename: Céline
authors.initials: C
authors.lastname: Masclaux-Daubresse
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D020231:Colletotrichum / Q000378:metabolism / Q000472:pathogenicity*; D009584:Nitrogen / Q000378:metabolism*; D027805:Phaseolus / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010940:Plant Proteins; D002734:Chlorophyll; D009584:Nitrogen