NMR-based metabolic study of leaves of three species of with different degrees of susceptibility to pv. .

Bacterial canker of , caused by the bacterium pv. (Psa), is the most serious disease of these plants worldwide. Leaves of three species of , namely var. , var. and , having different degrees of tolerance to Psa, were analyzed by Nuclear Magnetic Resonance spectroscopy. Aqueous extracts of leaves were studied and several metabolites, classified as organic acids, amino acids, carbohydrates, phenols and other metabolites, were identified by 1D and 2D NMR experiments and quantified. The metabolic profiles of these species were compared through univariate statistical analysis ANOVA and multivariate PCA. Levels of metabolites with known antibacterial activity, such as caffeic and chlorogenic acids, were observed to be higher in the samples. Moreover, these metabolites have different Pearson correlation patterns among the three species, suggesting a difference at the phenylpropanoid biosynthetic pathway.