title: Identification of UDP-glycosyltransferases involved in the biosynthesis of astringent taste compounds in tea (Camellia sinensis).
abstract: Galloylated catechins and flavonol 3-O-glycosides are characteristic astringent taste compounds in tea (Camellia sinensis). The mechanism involved in the formation of these metabolites remains unknown in tea plants. In this paper, 178 UGT genes (CsUGTs) were identified inC. sinensis based on an analysis of tea transcriptome data. Phylogenetic analysis revealed that 132 of these genes were clustered into 15 previously established phylogenetic groups (A to M, O and P) and a newly identified group R. Three of the 11 recombinant UGT proteins tested were found to be involved in the in vitro biosynthesis of β-glucogallin and glycosylated flavonols. CsUGT84A22 exhibited catalytic activity toward phenolic acids, in particular gallic acid, to produce β-glucogallin, which is the immediate precursor of galloylated catechin biosynthesis in tea plants. CsUGT78A14 and CsUGT78A15 were found to be responsible for the biosynthesis of flavonol 3-O-glucosides and flavonol 3-O-galactosides, respectively. Site-directed mutagenesis of the Q373H substitution for CsUGT78A14 indicated that the Q (Gln) residue played a catalytically crucial role for flavonoid 3-O-glucosyltransferase activity. The expression profiles of the CsUGT84A22, CsUGT78A14, and CsUGT78A15 genes were correlated with the accumulation patterns of β-glucogallin and the glycosylated flavonols which indicated that these three CsUGT genes were involved in the biosynthesis of astringent compounds inC. sinensis.
authors.affiliation: State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, China Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Lilan
authors.initials: L
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, China.
authors.forename: Shengbo
authors.initials: S
authors.lastname: Yao
authors.affiliation: School of Life Science, Anhui Agricultural University, Hefei, Anhui 230036, China.
authors.forename: Xinlong
authors.initials: X
authors.lastname: Dai
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Qinggang
authors.initials: Q
authors.lastname: Yin
authors.affiliation: School of Life Science, Anhui Agricultural University, Hefei, Anhui 230036, China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, China.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, China.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Qian
authors.affiliation: Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China xiatao62@126.com gaolp62@126.com yzhpang@ibcas.ac.cn.
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Pang
authors.affiliation: School of Life Science, Anhui Agricultural University, Hefei, Anhui 230036, China xiatao62@126.com gaolp62@126.com yzhpang@ibcas.ac.cn.
authors.forename: Liping
authors.initials: L
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, China xiatao62@126.com gaolp62@126.com yzhpang@ibcas.ac.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Xia
mesh_terms: D000818:Animals; D001252:Astringents; D053898:Biosynthetic Pathways; D028241:Camellia sinensis / Q000201:enzymology* / Q000235:genetics*; D002851:Chromatography, High Pressure Liquid; D057075:Enzyme Assays; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D016695:Glycosyltransferases / Q000378:metabolism*; D007700:Kinetics; D055432:Metabolomics; D016297:Mutagenesis, Site-Directed; D010802:Phylogeny; D018515:Plant Leaves / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020539:Sequence Analysis, Protein; D040681:Structural Homology, Protein; D013379:Substrate Specificity; D013649:Taste; D013662:Tea / Q000737:chemistry*; D014530:Uridine Diphosphate / Q000378:metabolism*
chemical_list: D001252:Astringents; D012333:RNA, Messenger; D013662:Tea; D014530:Uridine Diphosphate; D016695:Glycosyltransferases; D005964:Glucosyltransferases; C023249:flavonol 3-O-glucosyltransferase
keywords: Astringent taste compounds; Camellia; UDP-glycosyltransferase.; biosynthesis; flavonol 3-O-glycosides; galloylated catechins; sinensis