S-Glycosylation of Fluensulfone in Tomatoes: An Important Way of Fluensulfone Metabolism

Fluensulfone (FSF) becomes increasingly popular because of its nonfumigation application method. However, studies on the metabolic mechanism of FSF in plants are lacking. Here, tomato seedling was cultivated in hydroponic media to investigate the connection among FSF's metabolism in tomato, the regulation of tomato endogenous glycosides, and the elimination of hydrogen peroxide in tomato cells. The accumulation of FSF was only detected in the lower stems of tomatoes; FSF was mainly metabolized into S-glycosylated conjugates in the roots, and the roots were the tissues with the highest metabolite content; and no FSF and metabolites were detected in the upper leaves. In response to FSF stress (2 mg/L for 7 d), the content of sugar and glycosides in the stems of tomato seedlings significantly increased. The amount of some compounds on the pathway related to glucose was affected by FSF. The three precursor compounds (homomethioine, isoleucine, and l-tyrosine) in the pathway of glucosinolate biosynthesis increased significantly under the stress of FSF, which indicates that FSF may compete with them for UGT74B1. Besides, FSF-induced flavonoid glycosides may play a role in the process of removing hydrogen peroxide. This research provides inspiration for the fate of many xenobiotics containing sulfonyl groups in plants.