Functional importance of the family 1 glucosyltransferase UGT72B1 in the metabolism of xenobiotics in Arabidopsis thaliana
Functional importance of the family 1 glucosyltransferase UGT72B1 in the metabolism of xenobiotics in Arabidopsis thaliana
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DOI：
10.1111/j.1365-313x.2005.02398.x
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发表时间：
2005-05-01
期刊：
影响因子：
7.2
通讯作者：
Edwards, R
中科院分区：
文献类型：
--
作者：
Brazier-Hicks, M;Edwards, R
拟南芥1型UDP-葡萄糖依赖性葡萄糖基转移酶UGT 72 B1在结合持久性污染物3，4-二氯苯胺（DCA）和2，4，5-三氯苯酚（TCP）方面具有高度活性。为了确定其在植物中解毒外源性物质的重要性，已经表征了其中相应基因已被T-DNA插入破坏的突变植物。来自敲除ugt 72 B1植物的提取物显示对DCA和TCP的缀合活性彻底降低，并且不存在免疫可检测的UGT 72 B1蛋白。相反，对酚类天然产物的活动不受影响。当无菌根培养物被喂食[C-14]-DCA时，与野生型相比，ugt 72 B1植物显示出降低的异生素摄取速率和非常少的代谢为可溶性DCA-葡萄糖或相关的极性缀合物。相反，敲除积累了不可提取的放射性残留物，最有可能与木质化。当用[C-14]-TCP进行饲喂研究时，野生型和敲除型中的代谢速率和途径相同，TCP-葡糖苷是两种情况下的主要产物。在用野生型和ugt 72 B1突变体进行的全植物研究中获得了对DCA和TCP代谢的类似差异效应，这表明虽然UGT 72 B1在拟南芥中代谢氯苯胺中具有核心作用，但额外的UGT可以补偿敲除中TCP的缀合。TCP对野生型和ugt 72 B1植物同样有毒，而令人惊讶的是，敲除对DCA不太敏感。由此可以得出结论，DCA的葡糖基化在异生物质解毒中可能不如结合残基形成有效。
The Arabidopsis type 1 UDP-glucose-dependent glucosyltransferase UGT72B1 is highly active in conjugating the persistent pollutants 3,4-dichloroaniline (DCA) and 2,4,5-trichlorophenol (TCP). To determine its importance in detoxifying xenobiotics in planta, mutant plants where the respective gene has been disrupted by T-DNA insertion have been characterized. Extracts from the knockout ugt72B1 plants showed radically reduced conjugating activity towards DCA and TCP and the absence of immunodetectable UGT72B1 protein. In contrast, activities towards phenolic natural products were unaffected. When aseptic root cultures were fed [C-14]-DCA, compared with wild types, the ugt72B1 plants showed a reduced rate of uptake of the xenobiotic and very little metabolism to soluble DCA-glucose or associated polar conjugates. Instead, the knockouts accumulated non-extractable radioactive residues, most probably associated with lignification. When the feeding studies were carried out with [C-14]-TCP, rates and routes of metabolism were identical in the wild type and knockouts, with TCP-glucoside a major product in both cases. Similar differential effects on the metabolism of DCA and TCP were obtained in whole plant studies with wild type and ugt72B1 mutants, demonstrating that while UGT72B1 had a central role in metabolizing chloroanilines in Arabidopsis, additional UGTs could compensate for the conjugation of TCP in the knockout. TCP was equally toxic to wild type and ugt72B1 plants, while surprisingly, the knockouts were less sensitive to DCA. From this it was concluded that the glucosylation of DCA may not be as effective in xenobiotic detoxification as bound-residue formation.