Biotechnology of Natural Products, Technische Universität München , Liesel-Beckmann-Strasse 1, 85354 Freising, Germany.
Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory , Pune 411 008 Maharashtra, India.
J Agric Food Chem. 2017 Jul 19;65(28):5681-5689. doi: 10.1021/acs.jafc.7b01886. Epub 2017 Jul 7.
Vinification of grapes (Vitis vinifera) exposed to forest fire smoke can yield unpalatable wine due to the presence of taint compounds from smoke and the release of smoke derived volatiles from their respective glycosides during the fermentation process or in-mouth during consumption. To identify glycosyltransferases (GTs) involved in the formation of glycosidically bound smoke-derived volatiles we performed gene expression analysis of candidate GTs in different grapevine tissues. Second, substrates derived from bushfire smoke or naturally occurring in grapes were screened with the candidate recombinant GTs. A resveratrol GT (UGT72B27) gene, highly expressed in grapevine leaves and berries was identified to be responsible for the production of the phenolic glucosides. UGT72B27 converted the stilbene trans-resveratrol mainly to the 3-O-glucoside. Kinetic analyses yielded specificity constants (k/K) of 114, 17, 9, 8, and 2 mM s for guaiacol, trans-resveratrol, syringol, methylsyringol, and methylguaiacol, respectively. This knowledge will help to design strategies for managing the risk of producing smoke-affected wines.
葡萄（Vitis vinifera）在森林火灾烟雾中的酿造过程可能会产生口感不佳的葡萄酒，这是由于烟雾中的异味化合物以及在发酵过程中或在口中消费时从各自的糖苷中释放的烟雾衍生挥发物的存在。为了鉴定与结合糖苷的烟雾衍生挥发物形成有关的糖基转移酶（GT），我们对不同葡萄组织中的候选 GT 进行了基因表达分析。其次，用候选重组 GT 筛选源自丛林火灾烟雾或在葡萄中自然存在的底物。在葡萄叶和浆果中高度表达的白藜芦醇 GT（UGT72B27）基因被鉴定为负责酚类糖苷的产生。UGT72B27 将芪类反式白藜芦醇主要转化为 3-O-葡萄糖苷。动力学分析得到对愈创木酚、反式白藜芦醇、丁香酚、甲基丁香酚和甲基愈创木酚的特异性常数（k/K）分别为 114、17、9、8 和 2 mM s。这些知识将有助于设计管理产生烟雾影响葡萄酒风险的策略。
