Key Laboratory of Pesticide Toxicology and Application Technique, College of Plant Protection, Shandong Agricultural University, Tai'an 271018, Shandong, PR China.
College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266000, PR China.
J Agric Food Chem. 2021 Jun 30;69(25):7168-7177. doi: 10.1021/acs.jafc.1c01294. Epub 2021 Jun 21.
Tripyrasulfone is a novel herbicide post-emergence applied in paddy fields. In this study, tripyrasulfone phytotoxicity and its mode of action were investigated. Within 3-7 days after treatment (DAT), tripyrasulfone caused strong bleaching symptoms on newly developed leaves of followed by necrosis prior to death within 14 DAT. By investigating pigment composition, photosynthetic activity and energy dissipation of treated with tripyrasulfone, the accumulation of phytoene and significant decreases in total carotenoids were observed; the photosystem II complex (PSII) reaction center and PSII-PSI electron transport chain were damaged; and the non-photochemical energy quenching and reactive oxygen species were significantly increased. Based on the reversion of bleaching symptoms in treated by the addition of homogentisic acid, it was hypothesized that tripyrasulfone blocks the biosynthesis of HGA, possibly by the inhibition of 4-hydroxyphenylpyruvate dioxygenase (HPPD). However, based on its chemical structure, tripyrasulfone may tend to be hydrolyzed in plants. Indeed, the hydrolyzed tripyrasulfone (HDT) inhibited the activity of HPPD from produced by , which was approximately 6 times less effective than mesotrione. Molecular docking showed that the HDT formed a stable bidentate interaction with the active center Fe chelation of HPPD.
三嘧啶砜是一种新型的稻田苗后除草剂。本研究调查了三嘧啶砜的植物毒性及其作用模式。在处理后 3-7 天（DAT）内，三嘧啶砜导致 叶片上出现强烈的白化症状，随后在 14 DAT 前坏死。通过研究三嘧啶砜处理后 的色素组成、光合作用活性和能量耗散，观察到类胡萝卜素的积累和总类胡萝卜素的显著减少；光系统 II 复合物（PSII）反应中心和 PSII-PSI 电子传递链受损；非光化学能量猝灭和活性氧显著增加。基于添加反式-对羟基苯丙酮酸后白化症状在处理的 中的逆转，推测三嘧啶砜阻断 HGA 的生物合成，可能是通过抑制 4-羟苯基丙酮酸双加氧酶（HPPD）。然而，根据其化学结构，三嘧啶砜在植物中可能容易水解。事实上，水解的三嘧啶砜（HDT）抑制了 产生的 HPPD 的活性，其抑制活性约为麦草畏的 6 倍。分子对接表明，HDT 与 HPPD 的活性中心 Fe 螯合形成稳定的双齿相互作用。
