Accumulation of isochorismate-derived 2,3-dihydroxybenzoic 3-O-beta-D-xyloside in arabidopsis resistance to pathogens and ageing of leaves.
An intricate network of hormone signals regulates plant development and responses to biotic and abiotic stress. Salicylic acid (SA), derived from the shikimate/isochorismate pathway, is a key hormone in resistance to biotrophic pathogens. Several SA derivatives and associated modifying enzymes have been identified and implicated in the storage and channeling of benzoic acid intermediates or as bioactive molecules. However, the range and modes of action of SA-related metabolites remain elusive. In Arabidopsis, Enhanced Disease Susceptibility 1 (EDS1) promotes SA-dependent and SA-independent responses in resistance against pathogens. Here, we used metabolite profiling of Arabidopsis wild type and eds1 mutant leaf extracts to identify molecules, other than SA, whose accumulation requires EDS1 signaling. Nuclear magnetic resonance and mass spectrometry of isolated and purified compounds revealed 2,3-dihydroxybenzoic acid (2,3-DHBA) as an isochorismate-derived secondary metabolite whose accumulation depends on EDS1 in resistance responses and during ageing of plants. 2,3-DHBA exists predominantly as a xylose-conjugated form (2-hydroxy-3-beta-O-D-xylopyranosyloxy benzoic acid) that is structurally distinct from known SA-glucose conjugates. Analysis of DHBA accumulation profiles in various Arabidopsis mutants suggests an enzymatic route to 2,3-DHBA synthesis that is under the control of EDS1. We propose that components of the EDS1 pathway direct the generation or stabilization of 2,3-DHBA, which as a potentially bioactive molecule is sequestered as a xylose conjugate.
Bartsch
Michael
M
Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, 50829 Cologne, Germany.
Bednarek
Paweł
P
Vivancos
Pedro D
PD
Schneider
Bernd
B
von Roepenack-Lahaye
Edda
E
Foyer
Christine H
CH
Kombrink
Erich
E
Scheel
Dierk
D
Parker
Jane E
JE
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002827:Chorismic Acid / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006027:Glycosides / Q000378:metabolism*; D062385:Hydroxybenzoates / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D009868:Oomycetes / Q000472:pathogenicity; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020156:Salicylic Acid / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C118837:EDS1 protein, Arabidopsis; D006027:Glycosides; D062385:Hydroxybenzoates; C010807:xylosides; C052985:isochorismic acid; C009135:2,3-dihydroxybenzoic acid; D002827:Chorismic Acid; D020156:Salicylic Acid