title: Metabolite profiling of Arabidopsis inoculated with Alternaria brassicicola reveals that ascorbate reduces disease severity.
abstract: The interaction between the pathogenic ascomycete Alternaria brassicicola and Arabidopsis was investigated by metabolite profiling. The effect of A. brassicicola challenge on metabolite levels was substantial, with nearly 50% of detected compounds undergoing significant changes. Mutations blocking ethylene, jasmonic acid, or ethylene signaling had little effect on metabolite levels. The effects of altering levels of some metabolites were tested by exogenous application during A. brassicicola inoculation. Gamma amino-butyric acid (GABA) or xylitol promoted, while trehalose and ascorbate inhibited, disease severity. GABA promoted, and ascorbate strongly inhibited, fungal growth in culture. Arabidopsis vtc1 and vtc2 mutants, that have low levels of ascorbate, were more susceptible to A. brassicicola. Ascorbate levels declined following A. brassicicola inoculation while levels of dehydroascorbate increased, resulting in a shift of the redox balance between these compounds in the direction of oxidation. These results demonstrate that ascorbate is an important component of resistance to this pathogen.
authors.affiliation: Department of Plant Biology, University of Minnesota, St. Paul, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Botanga
authors.forename: Gerit
authors.initials: G
authors.lastname: Bethke
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Gallie
authors.forename: Oliver
authors.initials: O
authors.lastname: Fiehn
authors.forename: Jane
authors.initials: J
authors.lastname: Glazebrook
mesh_terms: D000528:Alternaria / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism / Q000494:pharmacology*; D060467:Disease Resistance / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D054884:Host-Pathogen Interactions; D008353:Mannitol / Q000378:metabolism; D055432:Metabolomics; D009154:Mutation; D010084:Oxidation-Reduction; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; D008353:Mannitol; D005680:gamma-Aminobutyric Acid; C522629:GDP-L-galactose phosphorylase, Arabidopsis; D010744:Phosphoric Monoester Hydrolases; D001205:Ascorbic Acid