PTR-MS analysis of fungal VOCs for early detection of oak wilt

Traditional methods for diagnosing bacterial or fungal infections, such as cell culture, are comprehensive but time-consuming and subjective. Microbial volatile organic compound (VOC) analysis offers a faster alternative, though challenges such as low concentrations and chemical heterogeneity persist. Gas chromatography-mass spectrometry (GC-MS), while highly sensitive, requires lengthy sample preparation. This study presents a novel approach using proton transfer-reaction mass spectrometry (PTR-MS) for direct headspace analysis of fungal cultures, eliminating the need for preconcentration steps. By culturing microbes in wide-mouth glass jars with septum caps, VOC profiles were obtained in under 30 s for samples which were incubated for just 1 day, thus significantly reducing the diagnosis time. Using Bretziella fagacearum, a model organism known for its distinctive fruity odor linked to oak wilt disease, this method demonstrated enhanced accuracy and speed in detecting characteristic VOCs. The high sensitivity and rapid turnaround of this technique offer a promising alternative to traditional cell culture and GC-MS methods, providing faster, more reliable diagnostics and reducing both the complexity and time required for pathogen identification.