['Plants utilise various defence mechanisms against their potential biotic stressing agents such as viroids, viruses, bacteria or fungi and abiotic environmental challenges. Among them metabolic alteration is a common response in both compatible and incompatible plant-pathogen interactions. However, the identification of metabolic changes associated with defence response is not an easy task due to the complexity of the metabolome and the plant response. To address the problem of metabolic complexity, a metabolomics approach was employed in this study.', 'To identify a wide range of pathogen (citrus exocortis viroid, CEVd, or Pseudomonas syringae pv. tomato)-induced metabolites of tomato using metabolomics.', 'Nuclear magnetic resonance (NMR) spectroscopy in combination with multivariate data analysis were performed to analyse the metabolic changes implicated in plant-pathogen interaction.', 'NMR-based metabolomics of crude extracts allowed the identification of different metabolites implicated in the systemic (viroid) and hypersensitive response (bacteria) in plant-pathogen interactions. While glycosylated gentisic acid was the most important induced metabolite in the viroid infection, phenylpropanoids and a flavonoid (rutin) were found to be associated with bacterial infection.'] Does metabolic response of tomato leave upon different plant-pathogen interactions?