Six Uridine-Diphosphate Glycosyltransferases Catalyze the Glycosylation of Bioactive C13-Apocarotenols1
Six Uridine-Diphosphate Glycosyltransferases Catalyze the Glycosylation of Bioactive C13-Apocarotenols1
复制标题
六种尿苷二磷酸糖基转移酶催化生物活性 C13-脱胡萝卜素的糖基化1
DOI：
10.1104/pp.20.00953
复制
发表时间：
2020
期刊：
影响因子：
7.4
通讯作者：
Wilfried
中科院分区：
文献类型：
--
作者：
Guangxin;Putkaradze;Natalia;Bohnacker;Joncyk;Hoffmann;Thomas;Bernhardt;Härtl;Schwab;Wilfried
c13 -类伪胡萝卜素是类胡萝卜素衍生的氧化产物，在植物中具有重要的生理功能。尽管它们的生物合成途径已被广泛研究，但它们的代谢包括糖基化仍然知之甚少。候选尿苷-二磷酸糖基转移酶基因（UGTs）是基于与其他UGTs相比的高转录丰度而选择的，因为这些组织是类伪胡萝卜素糖苷的丰富来源。通过p450催化生物转化制备羟基化C13-apocarotenol底物，并建立了微生物/植物酶体系来合成糖苷。天然底物通过分离植物苷制备的生理苷元文库进行鉴定。总的来说，我们确定了6个催化C13-apocarotenols糖基化的ugt，其中Glc结合在环己烯环或丁烷侧链上。MpUGT86C10是一种优良的新型酶，可催化化感作用的3-羟基-α-damascone、3-氧-α-ionol、3-氧-7,8-二氢-α-ionol （Blumenol C）和3-羟基-7,8-二氢-β-ionol的糖基化，而萌发试验表明，类去甲异戊二烯糖苷比其苷元具有更高的植物毒性。c13 -类伪胡萝卜素的糖基化在植物中具有多种功能，包括增加苷元的化感活性，促进根渗出，并允许与丛枝菌根真菌共生。这些结果能够深入分析糖基化的类去甲异戊二烯化感化学物质的作用，类伪胡萝卜素在丛枝菌根定植过程中的生理功能，以及相关的类胡萝卜素稳态维持。
C13-apocarotenoids (norisoprenoids) are carotenoid-derived oxidation products that perform important physiological functions in plants. Although their biosynthetic pathways have been extensively studied, their metabolism including glycosylation remains poorly understood. Candidate uridine-diphosphate glycosyltransferase genes (UGTs) were selected based on their high transcript abundance in comparison with otherUGTsin vegetative tissues ofNicotiana benthamianaand peppermint (Mentha×piperita), as these tissues are rich sources of apocarotenoid glucosides. Hydroxylated C13-apocarotenol substrates were produced by P450-catalyzed biotransformation and microbial/plant enzyme systems were established for the synthesis of glycosides. Natural substrates were identified by physiological aglycone libraries prepared from isolated plant glycosides. In total, we identified six UGTs that catalyze the glucosylation of C13-apocarotenols, where Glc is bound either to the cyclohexene ring or the butane side chain. MpUGT86C10 is a superior novel enzyme that catalyzes the glucosylation of allelopathic 3-hydroxy-α-damascone, 3-oxo-α-ionol, 3-oxo-7,8-dihydro-α-ionol (Blumenol C), and 3-hydroxy-7,8-dihydro-β-ionol, whereas a germination test demonstrated the higher phytotoxic potential of a norisoprenoid glucoside in comparison to its aglycone. Glycosylation of C13-apocarotenoids has several functions in plants, including increased allelopathic activity of the aglycone, facilitating exudation by roots and allowing symbiosis with arbuscular mycorrhizal fungi. The results enable in-depth analysis of the roles of glycosylated norisoprenoid allelochemicals, the physiological functions of apocarotenoids during arbuscular mycorrhizal colonization, and the associated maintenance of carotenoid homeostasis.