Metabolomics in Biotic Stress: Insights into Potato Resistance to Powdery Scab

, and roots were collected at the stage of visible gall formation for analysis by high-resolution liquid chromatography-mass spectrometry (LC-MS/MS). Principal component analysis revealed a distinct metabolic profile in infected 'Gladiator' roots compared with both non-inoculated controls and infected 'Iwa' roots, indicating a stronger host metabolic response in the resistant cultivar. Among the annotated metabolites, cysteinyl-glycine (Cys-Gly), a central intermediate of glutathione turnover, was significantly more abundant in infected 'Gladiator' roots. The accumulation of Cys-Gly provides direct biochemical evidence linking enhanced glutathione cycling and GST activity to effective host defence. These findings highlight glutathione metabolism as a key component of potato resistance and demonstrate the value of metabolomics for additional validation of biochemical mechanisms underlying plant cultivar responses to biotic stress.