01948nas a2200217 4500008004100000245014600041210006900187260000800256300001400264490000700278520115500285100001801440700002101458700002001479700002701499700002301526700001501549700002101564700002101585856012401606 2017 eng d00aGlucosylation of smoke-derived volatiles in grapevine (vitis vinifera) is catalyzed by a promiscuous resveratrol/guaiacol glucosyltransferase0 aGlucosylation of smokederived volatiles in grapevine vitis vinif cJUL a5681-56890 v653 aVinification 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(cat)/K-m) of 114, 17, 9, 8, and 2 mM(-1) s(-1) 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.1 aHaratl, Katja1 aHuang, Fong-Chin1 aGiri, Ashok, P.1 aFranz-Oberdorf, Katrin1 aFrotscher, Johanna1 aShao, Yang1 aHoffmann, Thomas1 aSchwab, Wilfried uhttps://library.ncl.res.in/content/glucosylation-smoke-derived-volatiles-grapevine-vitis-vinifera-catalyzed-promiscuous02339nas a2200217 4500008004100000022001100041245014200052210006900194260000900263300001500272490000700287520156300294100002101857700001601878700002301894700001801917700001801935700002101953700002101974856012601995 2018 eng d a32078100aStructural and functional analysis of UGT92G6 suggests an evolutionary link between mono- and disaccharide glycoside-forming transferases0 aStructural and functional analysis of UGT92G6 suggests an evolut cAPR  a 862–8750 v593 a

Glycosylation mediated by UDP-dependent glycosyltransferase (UGT) is one of the most common reactions for the biosynthesis of small molecule glycosides. As glycosides have various biological roles, we characterized UGT genes from grapevine (Vitis vinifera). In silico analysis of VvUGT genes that were highly expressed in leaves identified UGT92G6 which showed sequence similarity to both monosaccharide and disaccharide glucoside-forming transferases. The recombinant UGT92G6 glucosylated phenolics, among them caffeic acid, carvacrol, eugenol and raspberry ketone, and also accepted geranyl glucoside and citronellyl glucoside. Thus, UGT92G6 formed mono- and diglucosides in vitro from distinct compounds. The enzyme specificity constant Vmax/Km ratios indicated that UGT92G6 exhibited the highest specificity towards caffeic acid, producing almost equal amounts of the 3- and 4-O-glucoside. Transient overexpression of UGT92G6 in Nicotiana benthamiana leaves confirmed the production of caffeoyl glucoside; however, the level of geranyl diglucoside was not elevated upon overexpression of UGT92G6, even after co-expression of genes encoding geraniol synthase and geraniol UGT to provide sufficient precursor. Comparative sequence and 3-D structure analysis identified a sequence motif characteristic for monoglucoside-forming UGTs in UGT92G6, suggesting an evolutionary link between mono- and disaccharide glycoside UGTs. Thus, UGT92G6 functions as a mono- and diglucosyltransferase in vitro, but acts as a caffeoyl glucoside UGT in N. benthamiana.

1 aHuang, Fong-Chin1 aGiri, Ashok1 aDaniilidis, Melina1 aSun, Guangxin1 aHärtl, Katja1 aHoffmann, Thomas1 aSchwab, Wilfried uhttps://library.ncl.res.in/content/structural-and-functional-analysis-ugt92g6-suggests-evolutionary-link-between-mono-and02450nas a2200289 4500008004100000022001400041245012900055210006900184260000800253300001200261490000700273520149600280653001301776653002401789653002301813653001601836653001601852100001801868700002001886700002301906700001801929700002701947700001601974700002101990700002102011856012802032 2019 eng d a0959-665800aSemirational design and engineering of grapevine glucosyltransferases for enhanced activity and modified product selectivity0 aSemirational design and engineering of grapevine glucosyltransfe cNOV a765-7750 v293 a

Uridine diphosphate-dependent glycosyltransferases (UGTs) catalyze the transfer of a diversity of sugars to several acceptor molecules and often exhibit distinct substrate specificity. Modulation of glycosyltransferases for increased catalytic activity and altered substrate or product specificity are the key manipulations for the biotechnological use of glycosyltransferases in various biosynthetic processes. Here, we have engineered the binding pocket of three previously characterized Vitis vinifera glycosyltransferases, UGT88F12, UGT72B27 and UGT92G6, by structure-guided in silico mutagenesis to facilitate the interactions of active site residues with flavonol glucosides and thus modify substrate specificity and activity. Site-directed mutagenesis at selected sites, followed with liquid chromatography-mass spectrometry based activity assays, exhibited that mutant UGTs were altered in product selectivity and activity as compared to the wild-type enzymes. Mutant UGTs produced larger amounts of flavonol di-monosaccharide glucosides, which imply that the mutations led to structural changes that increased the volume of the binding pocket to accommodate a larger substrate and to release larger products at ease. Mutants showed increased activity and modified product specificity. Thus, structure-based systematic mutations of the amino acid residues in the binding pocket can be explored for the generation of engineered UGTs for diverse biotechnological applications.

10aflavonol10aGlycosyltransferase10ain silico analysis10aMutagenesis10aselectivity1 aJoshi, Rakesh1 aTrinkl, Johanna1 aHaugeneder, Annika1 aHaertl, Katja1 aFranz-Oberdorf, Katrin1 aGiri, Ashok1 aHoffmann, Thomas1 aSchwab, Wilfried uhttps://library.ncl.res.in/content/semirational-design-and-engineering-grapevine-glucosyltransferases-enhanced-activity-and02606nas a2200265 4500008004100000022001400041245009700055210006900152260000800221300001100229490000800240520174200248653001601990653001202006653001402018653002002032653005502052100001602107700001802123700001702141700002102158700002102179700001602200856012402216 2026 eng d a0981-942800aPhenylpropanoid-specific glycosyltransferases from mango and their potential role in defense0 aPhenylpropanoidspecific glycosyltransferases from mango and thei cMAR a1111370 v2323 a

Alphonso mango (Mangifera indica cv. Alphonso) is a cornerstone of India's fruit industry due to its distinct aroma and shelf-life characteristics. The uridine diphosphate-dependent glycosyltransferases (UGTs) play a crucial role in stabilising aroma and defense-related specialised metabolites in fruits. The present study explores the potential role of UGTs during mango ripening and Colletotrichum gloeosporioides infection. Gene expression analysis indicated that UGTs showed dynamic expression in skin and pulp during ripening. Phylogenetic analysis revealed substrate-driven divergence of UGTs, with MiUGT92A14 and MiUGT95B15 forming distinct clades associated with flavonoid glycosylation. Recombinant UGTs showed a higher preference for UDP-glucose, which is corroborated by the high accumulation of UDP-glucose during ripening. Furthermore, it was observed that MiUGT92A14 prefers phenolic acids as substrates, while MiGT95B15 shows flavonoid specificity. Spore germination assays demonstrated that both aglycones and their glycosylated derivatives suppressed early fungal morphogenesis, supporting a role for UGT-mediated glycosylation in maintaining defense-related metabolites in a bioactive yet non-toxic form during fruit ripening. Additionally, Colletotrichum gloeosporioides inhibition assays demonstrated that glycosylated products of selected UGTs exhibited equal or enhanced antifungal activity compared with their aglycone forms, indicating that glycosylation promotes the safe accumulation of antifungal compounds by reducing aglycone toxicity to the plant. These findings suggest that glycosylation of specific metabolites is a key for ripening process and to potentiate defence against fungal pathogen.

10aAnthracnose10adefense10aFlavonoid10aGlycoconjugates10aUridine diphosphate-dependent glycosyl-transferase1 aVare, Tejas1 aJoshi, Rakesh1 aLiao, Jieren1 aHoffmann, Thomas1 aSchwab, Wilfried1 aGiri, Ashok uhttps://library.ncl.res.in/content/phenylpropanoid-specific-glycosyltransferases-mango-and-their-potential-role-defense