PDF(Pubmed)
Abstract：
Sulcotrione is a member of triketone herbicides, a class of HPPD (4-hydroxyphenylpyruvate dioxygenase) inhibitors with broad-spectrum herbicidal activity. Modifications of glycosylation mediated by glycosyltransferases (GT) are involved in plant detoxification. In this study, we analyzed chip data published online and found that eight glycosyltransferases from group A of the apple glycosyltransferase family 1 may be involved in the metabolic mechanism of detoxification of triketone herbicides. To verify this prediction, we induced apple seedlings with six types of triketone herbicides, and then detected the expression levels of eight glycosyltransferase genes through real-time PCR. We found that triketone herbicides induced up-regulation of eight glycosyltransferase genes to varying degrees, with MdUGT91AJ2 being the most significantly up-regulated by sulcotrione-induced glycosyltransferase gene expression. Then, through in vitro enzymatic reactions and HPLC identification of glycoside substrates, it was found that the glycosyltransferase MdUGT91AJ2 had the highest specific enzyme activity against the triketone herbicide sulcotrione. Furthermore, the in vivo mechanism of the glycosyltransferase MdUGT91AJ2 in the detoxification metabolism of sulcotrione was further validated by overexpressing the strain in the plant. HPLC analysis showed that the content of sulcotrione glycosides in the overexpressing strain of MdUGT91AJ2 was significantly higher than that in the wild type. This result indicated that the apple glycosyltransferase MdUGT91AJ2 can still glycosylate and modify sulfotrione in plants, and participate in its detoxification metabolism. In summary, this study identified for the first time a novel apple glycosyltransferase MdUGT91AJ2 and elucidated its mechanism of action in the detoxification and metabolism of the triketone herbicide sulfotriene.
摘要：
磺草酮是三酮除草剂的成员，一类具有广谱除草活性的HPPD（4-羟基苯基丙酮酸双加氧酶）抑制剂。糖基转移酶（GT）介导的糖基化修饰涉及植物解毒。在这项研究中,我们分析了网上发表的芯片数据，发现苹果糖基转移酶家族1的A组8个糖基转移酶可能参与了三酮除草剂解毒的代谢机制。要验证此预测，我们用六种三酮除草剂诱导苹果幼苗，然后通过实时荧光定量PCR检测8个糖基转移酶基因的表达水平。我们发现三酮除草剂不同程度地诱导8个糖基转移酶基因上调,其中MdUGT91AJ2是硫磺三酮诱导的糖基转移酶基因表达最显著上调的。然后，通过体外酶促反应和高效液相色谱法鉴定糖苷底物，发现糖基转移酶MdUGT91AJ2对三酮除草剂硫三酮具有最高的比酶活性。此外，通过在植物中过表达该菌株，进一步验证了糖基转移酶MdUGT91AJ2在舒草酮解毒代谢中的体内机制。HPLC剖析显示，过表达菌株MdUGT91AJ2的磺草酮苷含量明显高于野生型。这一结果表明，苹果糖基转移酶MdUGT91AJ2仍然可以在植物中糖基化和修饰磺胺三酮，并参与其解毒代谢。总之,这项研究首次鉴定了一种新型的苹果糖基转移酶MdUGT91AJ2，并阐明了其在三酮除草剂磺三烯的解毒和代谢中的作用机制。
