Elucidating the occurrence patterns of Alternaria toxin tenuazonic acid in individual tomatoes through MALDI-MSI and LC-MS/MS.

Tomato (Solanum lycopersicum) is susceptible to Alternaria fungi, accumulating Alternaria toxins including tenuazonic acid (TeA). Previous studies have primarily focused on overall contamination levels; however, this study employs MALDI-MSI and LC-MS/MS techniques to provide the first detailed analysis of the spatial distribution and average levels of TeA in individual tomatoes. Among 77 lesioned processing tomato samples, the exceedance rate of TeA was notably high. MALDI-MSI reveals TeA's spatial distribution, while LC-MS/MS offers quantitative data but is affected by sample processing. Specially, We found internal fungal colonization causing outward lesions with decreasing core-to-surface TeA. Artificial inoculation experiments elucidate the infection dynamics of Alternaria alternata and TeA accumulation over time. The tgCotA line exhibited significant resistance to A. alternata and a significant reduction in TeA content, while the tgChitinase line showed an increase in TeA content. This study provides novel strategies for control of TeA in tomatoes and their derived products.