Unraveling the Metabolic Enigma: A High-Resolution LC–MS Approach to Decipher Two Triazine Herbicides Tolerance in Radish and Rice

Our study investigated the effects of terbuthylazine (TBA) and metribuzin (MT) on rice and radish at field application concentrations. Both herbicides induced oxidative stress and severely inhibited growth in the two crops. However, the radish cultivar T-33 exhibited significantly lower stress levels compared to the sensitive cultivar S-24, suggesting its higher tolerance to TBA and MT. To explore the potential role of metabolism in this tolerance, we developed a novel HPLC-Q-TOF-MS method, which demonstrated excellent performance and identified 18 TBA and 20 MT metabolites, most of which were discovered in plants for the first time. The results revealed significantly higher accumulation of both herbicides in rice compared to radish, especially in the aerial parts, with increasing translocation in rice and the opposite trend in radish. Quantitative analysis revealed significantly higher levels of glycosylated MT products and amino acid conjugates in T-33 compared to S-24, suggesting their crucial role in detoxification and tolerance mechanisms. Our findings have significant implications for food safety, crop protection, and sustainable agricultural practices in regions employing vegetable–crop rotation systems.