Chemical profiling of healthy and infected watermelon (Citrullus lanatus) affected by bacterial fruit blotch using gas chromatography–mass spectrometry

Acidovorax citrulli is the causative agent for bacterial fruit blotch in melons and watermelons. This disease causes several problems in the production and consumption of watermelon. The knowledge of the chemical profile of the interaction between the bacteria and the fruit can help in the adoption of measures to control this disease. Thus, this study investigated the volatile organic compounds (VOCs) in the fruit and seed of infected and healthy watermelon. In the present study, we used headspace-solid phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS). Chemometric analysis, Hierarchical cluster analysis (HCA) and Principal component analysis (PCA), was used and the results show that this technique associate to GC–MS can be used to differentiate healthy from infected samples. Phenylethyl alcohol was produced by bacteria cultivated in vitro as well as in infected fruits and healthy and infected seeds. Therefore, detection of some phenolic compounds (phenol, benzyl alcohol, p-cresol and 2-mehoxy-phenol), acetoin and 2,3-butanediol was observed in the infected samples, which indicated the presence of a possible defense mechanism against infection.