Herbicide pyrazolate causes cessation of carotenoids synthesis in early watergrass by inhibiting 4-hydroxyphenylpyruvate dioxygenase
Herbicide pyrazolate causes cessation of carotenoids synthesis in early watergrass by inhibiting 4-hydroxyphenylpyruvate dioxygenase
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除草剂吡唑酯通过抑制 4-羟苯基丙酮酸双加氧酶导致早期水草类胡萝卜素合成停止
DOI：
10.1046/j.1445-6664.2002.00046.x
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
J. Kadotani
中科院分区：
文献类型：
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作者：
H. Matsumoto;Morihiro Mizutani;T. Yamaguchi;J. Kadotani
在水溶液中，除草剂吡唑酯[4-（2，4-二氯苯甲酰基）-1，3-二甲基-5-吡唑基对甲苯磺酸酯]迅速水解为去甲磺酰基吡唑酯（DTP），4-（2，4-二氯苯甲酰基）-1，3-二甲基-5-羟基吡唑，这是除草剂的活性形式。本研究旨在探讨吡唑酯和DTP对敏感杂草早生禾本科杂草（Echinochloa oryzicola Vasing）类胡萝卜素合成的影响。此外，它们在体外对4-羟苯丙酮酸双加氧酶（HPPD）的影响进行了测定。将两叶期植物的根浸泡在含有0.5%体积丙酮的吡唑酯（5 × 10-5 mol L-1）或氟草酮（10-6 mol L-1）溶液中24小时。在第一次取样时（处理后3d：3DAT），吡唑处理植株的三叶叶绿素含量与未处理对照相比没有差异，但在3 ~ 6DAT之间有所下降。早水草三叶中β-胡萝卜素的下降规律与叶绿素的下降规律非常相似。这两种除草剂诱导更大的积累八氢番茄红素在第三片叶的早期水草3 DAT，并保持到9 DAT的水平。然而，饲料的尿黑酸减少八氢番茄红素的积累，只有在吡唑处理的植物，这表明该网站的除草剂的作用位于质体醌合成的途径。在HPPD试验中，DTP显示抑制酶的IC 50值为13 nmol L−1，吡唑盐的IC 50值为52 nmol L−1。在用于测定的吡唑盐溶液中，一些除草剂可能已经水解成DTP。结果表明，吡唑啉酮抑制类胡萝卜素合成并引起叶片漂白的机理与氟草松相似，但其作用位点不是八氢番茄红素脱氢酶，而是HPPD。
In aqueous solution, the herbicide pyrazolate [4-(2,4-dichlorobenzoyl)-1,3-dimethyl-5-pyrazolyl p-toluenesulfonate] is rapidly hydrolyzed to destosyl pyrazolate (DTP), 4-(2,4-dichlorobenzoyl)-1,3-dimethyl-5-hydroxypyrazole, which is an active form of the herbicide. The objective of this study was to examine the effect of pyrazolate and DTP on carotenoids synthesis in susceptible weed, early watergrass (Echinochloa oryzicola Vasing.). Furthermore, their in vitro effect on 4-hydroxyphenylpyruvate dioxygenase (HPPD) was determined. Roots of the plants at the two-leaf stage were soaked for 24 h into pyrazolate (5 × 10–5 mol L−1) or norflurazon (10–6 mol L−1) solution containing 0.5% volume of acetone. At the first sampling time (3 days after treatment: 3 DAT), the chlorophyll content in the third leaves of pyrazolate-treated plants were not different compared with the untreated control, but it was decreased between 3 and 6 DAT. The declining pattern of β-carotene in the third leaf of early watergrass was very similar to that of chlorophyll. Both herbicides induced greater accumulation of phytoene in the third leaves of early watergrass 3 DAT, and the levels were kept until 9 DAT. However, feeding of homogentisate reduced the phytoene accumulation only in pyrazolate-treated plants, suggesting the site of action of the herbicide located in the pathway of plastoquinone synthesis. In a HPPD assay, DTP revealed to inhibit the enzyme with an IC50 value of 13 nmol L−1 and that of pyrazolate was 52 nmol L−1. In the pyrazolate solution used in the assay, some of the herbicide possibly has been hydrolyzed to DTP. From the all results obtained, it is strongly suggested that pyrazolate inhibits carotenoids synthesis and causes bleaching on the developing leaves by the similar mechanism with norflurazon, but its action site is not phytoene desaturase and is HPPD.