title: Engineering salidroside biosynthetic pathway in hairy root cultures of Rhodiola crenulata based on metabolic characterization of tyrosine decarboxylase.
abstract: Tyrosine decarboxylase initializes salidroside biosynthesis. Metabolic characterization of tyrosine decarboxylase gene from Rhodiola crenulata (RcTYDC) revealed that it played an important role in salidroside biosynthesis. Recombinant 53 kDa RcTYDC converted tyrosine into tyramine. RcTYDC gene expression was induced coordinately with the expression of RcUDPGT (the last gene involved in salidroside biosynthesis) in SA/MeJA treatment; the expression of RcTYDC and RcUDPGT was dramatically upregulated by SA, respectively 49 folds and 36 folds compared with control. MeJA also significantly increased the expression of RcTYDC and RcUDPGT in hairy root cultures. The tissue profile of RcTYDC and RcUDPGT was highly similar: highest expression levels found in stems, higher expression levels in leaves than in flowers and roots. The gene expressing levels were consistent with the salidroside accumulation levels. This strongly suggested that RcTYDC played an important role in salidroside biosynthesis in R. crenulata. Finally, RcTYDC was used to engineering salidroside biosynthetic pathway in R. crenulata hairy roots via metabolic engineering strategy of overexpression. All the transgenic lines showed much higher expression levels of RcTYDC than non-transgenic one. The transgenic lines produced tyramine, tyrosol and salidroside at higher levels, which were respectively 3.21-6.84, 1.50-2.19 and 1.27-3.47 folds compared with the corresponding compound in non-transgenic lines. In conclusion, RcTYDC overexpression promoted tyramine biosynthesis that facilitated more metabolic flux flowing toward the downstream pathway and as a result, the intermediate tyrosol was accumulated more that led to the increased production of the end-product salidroside.
authors.affiliation: Agricultural and Animal Husbandry College, Tibet University, Nyingchi of Tibet, P. R. China ; Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Engineering and Technology Research Center for Sweetpotato, School of Life Sciences, Southwest University, Chongqing, P. R. China.
authors.forename: Xiaozhong
authors.initials: X
authors.lastname: Lan
authors.forename: Kai
authors.initials: K
authors.lastname: Chang
authors.forename: Lingjiang
authors.initials: L
authors.lastname: Zeng
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Liu
authors.forename: Fei
authors.initials: F
authors.lastname: Qiu
authors.forename: Weilie
authors.initials: W
authors.lastname: Zheng
authors.forename: Hong
authors.initials: H
authors.lastname: Quan
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Liao
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Wenlin
authors.initials: W
authors.lastname: Huang
authors.forename: Wanhong
authors.initials: W
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
mesh_terms: D035264:Flowers / Q000235:genetics / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D029771:Rhodiola / Q000235:genetics / Q000378:metabolism*; D014445:Tyrosine Decarboxylase / Q000235:genetics / Q000378:metabolism*
chemical_list: D005960:Glucosides; D010636:Phenols; D014445:Tyrosine Decarboxylase; C009172:rhodioloside