Abstract: In order to investigate the occurrence patterns of Alternaria toxins in tomato fruit infected with Alternaria, fresh tomatoes were artificially injured, inoculated with a spore suspension of Alternaria spp. tomato and stored at 4 or 25 ℃ for 15 days. Samples were taken at three intervals for analysis by high resolution mass spectrometry (HRMS), and the obtained data were analyzed using MZmine and Xcalibur software. The original mass spectral dataset was processed by MZmine and imported into the global natural products social molecular networking platform to establish a molecular network for visual analysis of the metabolic pathways of Alternaria toxins using feature-based molecular networking (FBMN). The results showed that no toxins occurred in inoculated tomato after storage at 4 ℃. Alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA) and tentoxin (TEN) were all detected after 5, 10 and 15 days of storage at 25 ℃, and altenuene (ALT) was detected only on day 15, with TeA being detected at the highest level in all three samples. The presence of hidden toxins combined with AOH and AME sulfate was confirmed by using the Diagnostic Fragmentation Filtering (DFF) function in MZmine and through exact mass measurement with Xcalibur software. The metabolic pathway diagram established based on FBMN showed that AOH, AME and TeA had more relational networks, and TEN and ALT molecular nodes existed in isolation. This research may provide theoretical support for controlling the occurrence of Alternaria oxins in tomatoes and its preservation.

Key words: tomato; Alternaria spp.; Alternaria toxins; hidden toxins; metabolic pathway