Chemometric evaluation of volatile organic compounds as diagnostic markers for infections of potato tubers with Rhizoctonia solani and Alternaria solani

Reliable detection of potato pathogens via volatile organic compound (VOC) analysis remains challenging because VOC emissions depend strongly on microbial metabolism and host physiology. In this study, gas chromatography-mass spectrometry (GC–MS) data combined with a multivariate chemometric workflow were used to characterize VOC profiles of potato tubers infected with Rhizoctonia solani and Alternaria solani , and to compare these profiles with the emissions produced by the respective fungi grown on LB agar plates. VOCs were collected on thermal desorption tubes and analyzed with GC-MS. Principal component analysis (PCA) and linear discriminant analysis (LDA) achieved high classification accuracies (≥ 80 %) across all sample classes, demonstrating the robustness of the analytical approach. Three C8 oxylipins, 1-octen-3-one, 1-octen-3-ol, and 3-octanone, were associated with R. solani infected potato tubers. For A. solani , 14 diagnostic VOCs were detected in infected tubers, including α-himachalene, β-cedrene, thujopsene, eremophilene, and solavetivone. VOC patterns from LB cultures differed substantially from those observed in infected tubers, underscoring the strong substrate dependence of fungal volatile production. Altogether, this work provides novel host-relevant diagnostic markers for early pathogen detection and demonstrates that chemometric evaluation of complex VOC datasets is a powerful tool for discriminating potato diseases.